@article { ISI:000227321900006, title = {Hydrophobically modified poly(acrylic acid) using 3-pentadecylcyclohexylamine: synthesis and rheology}, journal = {Macromolecular Chemistry and Physics}, volume = {206}, number = {4}, year = {2005}, month = {FEB}, pages = {464-472}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

Hydrophobically modified poly(acrylic acid) was synthesized using 3-pentadecylcyclohexylamine (3-PDCA), which was in turn synthesized from 3-pentadecylphenol, one of the components of cashew-nut shell liquid (CNSL), a renewable resource material. H-1 NMR spectra confirmed the incorporation of 3-PDCA onto PAA and a series of HMPs with three different molar concentrations, viz. congruent to 3, 5 and 7 mol-\% of 3-PDCA, were synthesized. An increase in viscosity with increasing hydrophobic content was observed by rheological measurements. The critical association concentrations were determined using an Ubbelohde viscometer and a controlled stress rheometer. The stability of HMPs towards temperature and shear was studied. Rheological measurements showed that there was a steady increase in viscosity with increase in hydrophobe content due to the formation of reversible networks. These polymers exhibited gel-like behavior at low concentrations (greater than or equal to2 wt.-\%) with an apparent yield stress (ca. 10 Pa) and showed shear thinning properties (non-Newtonian). However, below a critical concentration, c [eta], they showed Newtonian behavior.

}, keywords = {3-pentadecylcyclohexylamine (3-PDCA), hydrophobically modified polymers (HMPs), poly(acrylic acid), reversible associations, Rheology}, issn = {1022-1352}, doi = {10.1002/macp.200400392}, author = {Shedge, A. S. and Lele, Ashish K. and Wadgaonkar, P. P. and Hourdet, Dominique and Pcrrin, P. and Chassenieux, Christophe and Badiger, Manohar V.} } @article { ISI:000230698100015, title = {Molecular origins of wettability of hydrophobic poly(vinylidene fluoride) microporous membranes on poly(vinyl alcohol) adsorption: Surface and interface analysis by XPS}, journal = {Journal of Physical Chemistry B}, volume = {109}, number = {29}, year = {2005}, month = {JUL}, pages = {13941-13947}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

irreversible adsorption of poly(vinyl alcohol) (PVA) on hydrophobic, porous poly(vinylidene fluoride) (PVDF) membranes was carried out using aqueous PVA solution. Water permeation was observed in PVDF microporous membranes after PVA adsorption, and maximum permeability was obtained after treatment with 4\% PVA solution. Water permeability increased linearly with increasing PVA concentration up to 4\%, and then a marginal decrease with a further increase in PVA concentration occurred. PVA adsorbed PVDF membranes were subjected to intense physicochemical analysis, especially with XPS. XPS results display the presence of an interface between PVA and PVDF, and the binding energy (BE) of the interface is low for the PVDF membranes treated with 4\% PVA. Carbon from CF2-groups and F 1s core level clearly showed a decrease in its content on the surface after PVA adsorption and showed a minimum fluorine content at 4\% PVA. F Is BE shifts by 0.5 eV upon PVA adsorption and is independent of PVA concentration. EDAX analysis indicates that the bulk oxygen content remains within 4.5 +/- 0.6\% and is independent of the PVA concentration. Nonetheless, a large amount of surface atom percentage of oxygen (20 +/- 4\%) from 0 Is core level shows an increase in PVA content on the surface of PVDF, and it is restricted mostly to the surface. The 4\% PVA treated PVDF membrane clearly shows a broadening of O 1s core level to lower BE and indicates the interaction between PVDF and PVA which is significantly different compared to any other compositions. A new valence band feature at low BE, which is nonexistent on PVDF, develops after PVA adsorption. This indicates that the shift in the nature of the highest occupied molecular orbital (HOMO) derived mostly from oxygen; simultaneously, a suppression in the PVDF derived band indicates the change in nature of the PVA adsorbed surfaces from hydrophobic to hydrophilic. The above observations also suggest an irreversible electronic interaction between PVA and PVDF, possibly through charge transfer.

}, issn = {1520-6106}, doi = {10.1021/jp050806r}, author = {Gholap, S. G. and Badiger, Manohar V. and Gopinath, Chinnakonda S.} } @article { ISI:000228658400021, title = {Morphology and chain dynamics during collapse transition of PNIPAM gels studied by combined imaging, relaxometry and Xe-129 spectroscopy techniques}, journal = {Magnetic Resonance Imaging}, volume = {23}, number = {2, SI}, year = {2005}, note = {7th International Conference on Magnetic Resonance in Porous Media (MRPM7), Palaiseau, FRANCE, JUL 04-08, 2004}, month = {FEB}, pages = {249-253}, publisher = {ELSEVIER SCIENCE INC}, address = {360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA}, abstract = {

The temperature-induced shape transition of poly(N-isopropylacrylamide) gels of different cross-link densities was investigated by a combination of NMR techniques allowing the characterization of both the macroscopic collapse as well as the changes on a molecular scale related to the expulsion of water from the gel network. The proton-containing gel phase was visualized by swelling in heavy water, and the volume change was monitored by proton imaging for cross-link densities between 0.5 \% and 2.5 \%. Above the transition temperature of 35 degrees C, gel collapse led to a volume change of up to a factor of 17 for the gel of smallest cross-link density. Two spectral lines of Xe-129 are found in the gel state and are assigned to the hydrophobic and hydrophilic parts of the network. In the collapsed state, the hydrophobic peak shows a strong shift while the hydrophilic peak disappears. A considerable shortening of both T-1 and T-2 of the gel protons upon collapse was found at a field of 4.7 T. At lower fields, the effect becomes more pronounced and qualitatively different dispersion behaviors between the swollen and the collapsed states are observed. (c) 2005 Elsevier Inc. All rights reserved.

}, keywords = {gel, networks, phase transition, relaxometry, Xe-129 spectroscopy}, issn = {0730-725X}, doi = {10.1016/j.mri.2004.11.019}, author = {Kariyo, Sobiroh and Kuppers, Markus and Badiger, Manohar V. and Prabhakar, A. and Jagadeesh, Bharatam and Stapf, S. and Blumich, B.} } @article { ISI:000234350400019, title = {Synthesis and swelling behaviour of hydrophobically modified responsive polymers in dilute aqueous solutions}, journal = {Polymer}, volume = {46}, number = {26}, year = {2005}, month = {DEC}, pages = {12190-12199}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

New series of associating polymers were synthesised in order to investigate opposite behaviours of hydrophobically modified water-soluble polymers and thermoresponsive water-soluble polymers carrying LCST stickers. On the basis of a poly(acrylic acid) backbone, amino-terminated poly(N-isopropylacrylamide), poly(ethylene oxide-co-propylene oxide) and/or dodecyl chains were grafted following a reaction of condensation activated by carbodiimide. Two homologous series of well-defined single grafted and double grafted copolymers were obtained, with double grafted chains containing both C12 and LCST grafts. The dilute solution properties of these copolymers were carefully studied by capillary viscometry. At low salt concentration and below the LCST of the grafts, the swelling properties of macromolecular chains are controlled either by intramolecular associations between hydrophobes, excluded volume effect exerted by hydrophilic grafts or by a balance between these opposite interactions. The deswelling of macromolecular chains, induced by hydrophobic interactions, is amplified at higher ionic strength and more particularly above the transition temperature of the side chains. (c) 2005 Elsevier Ltd. All rights reserved.

}, keywords = {associating polymers, poly(acrylic acid), viscometry}, issn = {0032-3861}, doi = {10.1016/j.polymer.2005.10.140}, author = {Iyer, N. P. and Hourdet, Dominique and Badiger, Manohar V. and Chassenieux, Christophe and Perrin, P. and Wadgaonkar, P.} } @article { ISI:000232218700049, title = {Thermoreversible behavior of associating polymer solutions: thermothinning versus thermothickening}, journal = {Macromolecules}, volume = {38}, number = {20}, year = {2005}, month = {OCT}, pages = {8512-8521}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Self-assembling properties of poly(sodium acrylate) grafted with dodecyl [C12], PAAgC12, or poly(N-isopropylacrylamide) [PNIPA] side chains, PAAgPNIPA, were studied in unentangled semidilute aqueous solution. While PAAgC12 self-associates through hydrophobic interactions, the gelation of PAAgPNIPA is triggered by heating in response to the lower critical solution temperature of PNIPA (LCST similar to 32 degrees C). The local structure of the physical networks was investigated by small-angle neutron scattering, and the scattering patterns were described using a polydisperse sphere model taking into account hard-sphere interactions. This model allow us to draw a realistic picture of physical gels with quantitative information concerning the size of hydrophobic cores, the volume fraction of stickers in the aggregates, the fraction of stickers which take part in the aggregation process, the range of repulsive interactions, and the structural modifications induced by temperature. The description of the network is in good agreement with complementary data obtained from DSC and C-13 NMR. In the present work, a special emphasis has been given to the important relationship existing between the viscoelastic properties of associating polymer solutions and the binding energy of stickers leaving temporarily the micellar junction. Depending on the endothermic or exothermic nature of the disengagement process of the sticker (heat of demicellization), the relaxation time of the network and the viscoelastic properties will either decrease or increase with the temperature. The consequence is that aqueous solutions of PAAgC12 and PAAgPNIPA exhibit opposite rheological properties with the temperature, namely thermothinning and thermothickening. By mixing these two copolymers, we show that intermediate properties can be obtained but in that case a microphase-separated network is obtained as a result of copolymer segregation.

}, issn = {0024-9297}, doi = {10.1021/ma050786r}, author = {Hourdet, Dominique and Gadgil, Jayant and Podhajecka, K. and Badiger, Manohar V. and Brulet, A. and Wadgaonkar, P. P.} } @article { ISI:000240085700003, title = {Synthesis and characterization of novel hydrophobically end-capped poly(ethylene oxide)s [PEOs]}, journal = {Macromolecular Symposia}, volume = {241}, year = {2006}, note = {Indo-French Symposium on Fibrillar Networks as Advanced Materials, Inst Charles Sadron, Strasbourg, FRANCE, SEP 21-23, 2005}, month = {JUL}, pages = {9-13}, publisher = {Indo-French Ctr Promot Adv Res; Indian Assoc Cultivat Sci; Kolkata; GUENET; CNRS}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

We report on the synthesis and characterization of a novel hydrophobically modified end-capped poly(ethylene oxide)s. The end-capping agent of this polymer was designed and synthesised from a renewable resource material namely, gallic acid (i.e. 3,4,5-trihydroxybenzoic acid), the byproduct of tannin industry. The hydroxyl groups at 3, 4 and 5 positions of gallic acid provide an opportunity for varying the hydrophobicity of the compound. The hydrophobic end-capping compound, 3,4,5tridodecyloxy bezoylazide was prepared from gallic acid and PEGS with different chain lengths (of number average molecular weights, 10000 and 35000 g/mol) were endcapped. using 3,4,5-tridodecyloxybenzoyl azide. The quantitative analysis of end-capping in the polymers was demonstrated by H-1-NMR spectroscopy and the rheological studies were carried out in the surfactant solutions.

}, keywords = {end-capped PEOs, hydrophobically modified polymers, water-soluble polymers}, issn = {1022-1360}, doi = {10.1002/masy.200650902}, author = {Badiger, Manohar V. and Kadam, Vijay S. and Lele, Ashish K. and Wadgaonkar, P. P. and Hourdet, Dominique} } @article { ISI:000243765100017, title = {Swelling and mechanical behavior of modified poly(vinyl alcohol)/laponite nanocomposite membranes}, journal = {Journal of Applied Polymer Science}, volume = {103}, number = {5}, year = {2007}, month = {MAR}, pages = {2896-2903}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Nanocomposite (NC) membranes based on hydrophobically modified PVA and laponite were synthesized with varying laponite content in the feed. The incorporation of laponite in NC membranes was investigated by FTIR spectroscopy and thermogravimetric analysis. The swelling ratio of membranes was determined as a function of temperature and laponite content. Swelling studies of NC membranes exhibited the decrease in swelling with an increase in laponite content in the NC membranes. The swelling ratio of NC membrane with 20\% laponite slightly increased with an increase in temperature. Dynamic mechanical analysis showed the systematic increase in storage modulus with laponite content, which indicates the enhancement of mechanical property upon laponite addition. There was also a decrease in the tan 6 peak values of NC membranes with an increase in laponite content in NCs. The permeabilities through NC membranes as a function of solute size and laponite content were studied and the results showed molecular screening based on size. The permeability of solute reduced due to the presence of well-dispersed laponite in the NC. (c) 2006 Wiley Periodicals, Inc.

}, keywords = {Dynamic mechanical analysis, laponite, membranes, nanocomposite hydrogel, poly(vinyl alcohol)}, issn = {0021-8995}, doi = {10.1002/app.25469}, author = {Nair, Shubhangi H. and Pawar, Kiran C. and Jog, Jyoti Prakash and Badiger, Manohar V.} } @article { ISI:000260640600003, title = {Intrinsic viscosity of aqueous solutions of carboxymethyl guar in the presence and in the absence of salt}, journal = {Macromolecular Chemistry and Physics}, volume = {209}, number = {20}, year = {2008}, month = {OCT}, pages = {2087-2093}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

Intrinsic viscosities were determined for solutions of CMG in pure water and 0.9 wt.-\% aqueous NaCl. To avoid the 0/0-type extrapolation typical for Huggins plots, a new procedure was used. For CMG and pure water, this requires only two adjustable parameters: the specific hydrodynamic volume of the polymer in the limit of infinite dilution and a hydrodynamic interaction parameter. The intrinsic viscosity of CMG (no salt) at room temperature is 6 050 mL . g(-1); approximately half as large as that of Na-PSS of comparable molar mass. The ratio of the intrinsic viscosities with and without salt is approximate to 7 for CMG, as compared to \>100 for Na-PSS. The reasons 1:5 5 for the different behaviors of the two types of polyelectrolytes are being discussed.

}, keywords = {Biopolymers, Carboxymethyl guar, intrinsic viscosity, polyelectrolyte, salt-free solutions}, issn = {1022-1352}, doi = {10.1002/macp.200800238}, author = {Badiger, Manohar V. and Gupta, Nivika R. and Eckelt, John and Wolf, Bernhard A.} } @article { ISI:000260062900021, title = {Synthesis and self-assembling properties of alpha,omega-hydroxy-poly(ethylene oxide) end-capped with 1-isocyanato-3-pentadecylcyclohexane}, journal = {Polymer}, volume = {49}, number = {21}, year = {2008}, month = {OCT}, pages = {4635-4646}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A novel hydrophobic compound, 1-isocyanato-3-pentadecylcyclohexane (PDC) issued from a renewable resource material (Cashew Nut Shell Liquid), is used to end-cap poly(ethylene oxide) (PEO) of different molecular weights. The synthesis, characterization and self-assembling properties of these new associating polymers are reported. In aqueous solution, PDC modified PEOs self-associate into micellar structures which are characterized by neutron scattering. Using a star-polymer model with sticky hard sphere interactions, it is shown that the characteristics of the micelles mainly depend on the size of the PEO chain. In the case of PDC stickers, the aggregation number decreases from 25 to 17 with increasing molecular weight of PEO, from 10 to 20 kg/mol, respectively. The temperature directly impacts the interaction potential between the hydrophilic coronas of PEO which become less repulsive with increasing temperature. Rheological measurements, performed in dilute solution, clearly demonstrate that PEO micelles self-associate into open supramolecular structures. The correlation length of these loose clusters increases with polymer concentration and the hierarchical self-assembly follows the rules of the percolation theory. The sol/gel transition takes place at the overlap concentration of clusters. In semi-dilute solution, the viscoelastic properties of PDC end-capped PEOs are well described by the Maxwell model with a single relaxation mode. The characteristic time of the network follows an Arrhenius temperature dependence with an activation energy of 70 kJ/mol, in very good agreement with the size of PDC stickers. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Associating polymer, Hydrophobically end-capped, poly(ethylene oxide), Star micelles}, issn = {0032-3861}, doi = {10.1016/j.polymer.2008.07.064}, author = {Kadam, Vijay S. and Badiger, Manohar V. and Wadgaonkar, Prakash P. and Ducouret, Guylaine and Hourdet, Dominique} } @article { ISI:000269877500009, title = {High energy electron irradiation effects on polystyrene films}, journal = {Radiation Effects and Defects in Solids}, volume = {164}, number = {10}, year = {2009}, month = {SEP}, pages = {PII 914466497}, publisher = {TAYLOR \& FRANCIS LTD}, address = {4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND}, abstract = {

The effect of an 8MeV electron-beam on the structural, optical and dielectric properties of polystyrene films has been investigated respectively by means of Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy and electrical impedance (LCR) analysis over a radiation dose in the range of 50-250kGy using a Microtron accelerator. The FTIR spectral analysis shows no change in the overall structure of the irradiated polystyrene films, except a minor change in the intensity of a few peaks in the FTIR spectrum, indicating that polystyrene is resistant to electron-beam irradiation over the range of radiation doses investigated. The optical band gap analysis using the UV-VIS absorption spectra of the polystyrene shows a small decrease in the optical band gap (Eg) and the activation energy with an increase in electron doses. Further, the dielectric measurements over a frequency range of 100Hz to 1MHz for the electron-beam-irradiated polystyrene films show that both the dielectric constant and the dielectric loss increase with an increase in electron radiation dose, which may be ascribed to the formation of defect sites in the band gap of polystyrene as a consequence of molecular chain scission in the polymer films upon irradiation.

}, keywords = {electrons, optical spectroscopy, Polymers, radiation}, issn = {1042-0150}, doi = {10.1080/10420150903173262}, author = {Mathad, R. D. and Kumar, H. G. Harish and Sannakki, B. and Ganesh, S. and Sarma, K. S. S. and Badiger, Manohar V.} } @article {43344, title = {Process for the preparation of polymeric absorbents }, number = {US 09/537,450}, year = {2009}, month = {JAN}, chapter = {US6794467 B2}, abstract = {The invention discloses a process for the preparation of polymeric absorbents useful for gelling organic liquids. The process comprises mixing one or more monomers with a cross-linking agent, a free radical initiator, an optional solvent, optionally in the presence of a transition metal source and subjecting the mixture so obtained to a conventional polymerisation method. The polymer is removed, crushed to obtain polymer powder, washed with solvent and dried by conventional methods to remove unreacted monomers, followed by swelling in alcohols to obtain the desired product.}, author = {Lele, Ashish Kishor and Varghese, Shyni and Badiger, Manohar V. and Mashelkar, Raghunath Anant} } @article { ISI:000284967000058, title = {Abrupt shear thickening of aqueous solutions of hydrophobically modified poly(N,N {\textquoteleft}-dimethylacrylamide-co-acrylic acid)}, journal = {Macromolecules}, volume = {43}, number = {23}, year = {2010}, month = {DEC}, pages = {10055-10063}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We report some new and interesting observations on the abrupt and large shear-induced thickening of aqueous solutions of hydrophobically modified poly(N,N{\textquoteright}-dimethylacrylamide-co-acrylic acid). High molecular weight copolymer was prepared by free radical copolymerization of N,N{\textquoteright}-dimethylacrylamide [DMA] and acrylic acid [AA] and was subsequently modified to different extents using a hydrophobic compound, namely, 3-pentadecylcyclohexylamine [3-PDCA], which is derived from a renewable resource material, cashew nutshell liquid [CNSL]. The structural elucidation of the base copolymer and the hydrophobically modified copolymers was performed by (1)H and (13)C NMR spectroscopy. The zero shear viscosities [eta(0)] of the hydrophobically modified polymers were lower than that of the precursor poly(N,N{\textquoteright}-dimethylacrylamide-co-acrylic acid) until some critical polymer concentration, which increased with increase in hydrophobic modification. Above the critical concentrations, the eta(0) of the hydrophobically modified copolymers surpassed that of the precursor at the same concentration. At moderate shear rates some of these hydrophobically modified copolymers exhibited an abrupt shear-induced thickening in which the viscosity of the samples increased severalfold. We show here from creep experiments that thickening occurs only when the shear rate reaches a critical value, (gamma) over dot(crit), and that the thickened samples can be trapped in different metastable states by controlling the applied stress. Interestingly, the shear thickened samples showed further thickening upon decreasing the applied stress. Eventually, the metastable samples revert to their equilibrium states at characteristic time that depends on (small) probe stress.

}, issn = {0024-9297}, doi = {10.1021/ma1017378}, author = {Lele, Ashish K. and Shedge, Aarti and Badiger, Manohar V. and Wadgaonkar, Prakash and Chassenieux, Christophe} } @article { ISI:000277423200006, title = {Hydrophobically modified poly(vinyl alcohol) using alkoxy-substituted methyl gallate: synthesis and rheology}, journal = {Journal of Polymer Science Part B-Polymer Physics}, volume = {48}, number = {10}, year = {2010}, month = {MAY}, pages = {1054-1063}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Hydrophobically modified poly(vinyl alcohol) (HMPVA) polymers were synthesized by potassium t-butoxide-catalyzed reaction of PVA with methyl 3,4,5-tris(n-octyloxy) benzoate (MGC(8))/3,4,5-tris(n-dodecyloxy) benzoate (MGC(12)) and 1,3-propane sultone. The concentration of 1,3-propane sultone was kept constant at 10 mol \%. and that of MGC(8) (2, 3, and 4 mol \%)/MGC(12) (2 and 3 mol \%) was varied to obtain HMPVAs with different hydrophobic contents. The incorporation of MGC(8)/MGC(12) and 1,3-propane sultone onto HMPVA was confirmed by NMR spectroscopy. Rheological properties of aqueous solutions also confirmed the presence of hydrophobic and charged functional groups on HMPVAs. In the semidilute regime, the specific viscosity of HMPVAs followed concentration scaling that is typical of polyelectrolytes. At higher concentrations, the HMPVA solutions with 3 and 4 mol \% of MGC(8) exhibited large increase in specific viscosity. Oscillatory experiments on these solutions exhibited gel-like behavior at polymer concentrations of 40-50 g/L. Confocal microscopy images of HMPVA with 4 mol \% of MGC(8) clearly indicated the existence of microgels. The tendency of formation of microgels further increased with increasing chain length of the hydrophobe, that is, with MGC(12). These samples exhibited rheological behavior that is typical of soft solids and was therefore probed by the strain-rate frequency superposition technique reported recently in the literature. HMPVAs with improved rheological properties show potential applications as thickeners in cosmetic creams, lotions and as drug carriers in pharmaceutical formulations. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1054-1063, 2010

}, keywords = {gallic acid, hydrophobically modified poly(vinyl alcohol), Rheology, water-soluble polymers}, issn = {0887-6266}, doi = {10.1002/polb.21995}, author = {Shedge, Aarti S. and Wadgaonkar, Prakash P. and Lele, Ashish K. and Badiger, Manohar V.} } @article { ISI:000277649500046, title = {Volume transition of PNIPAM in a nonionic surfactant hexagonal mesophase}, journal = {Macromolecules}, volume = {43}, number = {10}, year = {2010}, month = {MAY}, pages = {4782-4790}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We investigate the volume transition of a thermoresponsive polymer, poly(N-isopropylacrylamide), PNIPAM, in the presence of an aqueous solution of nonionic surfactant, C(12)E(9). We combine turbidimetry with optical microscopy, NMR, and SAXS to follow the volume transition of the PNIPAM and the H(1)-isotropic transition of the surfactant/water system. Nonionic surfactants such as C(12)E(9) are known to interact weakly with PNIPAM. Accordingly, we show that there is only a small change in the volume transition temperature for the PNIPAM in isotropic micellar solutions of C(12)E(9), even for relatively high concentrations of C(12)E(9). Interestingly, once the surfactant forms an H(1) phase, there is a dramatic decrease in the coil globule transition onset temperature. We believe that this behavior results from a competition between C(12)E(9) in the H(1) phase, and PNIPAM to associate with water. When PNIPAM in the H(1) phase is cooled to low enough temperatures so as to be in the coil state, it locally disturbs the hexagonal phase ordering. Thus, we show that for PNIPAM in a weakly interacting surfactant matrix, it is the phase behavior of the matrix rather than the matrix chemistry that governs the coil globule transition. Finally, we show that in a PNIPAM copolymer with a higher LCST we observe an interesting sequence of transitions in the surfactant phase: on cooling from a high temperature free-blowing turbid globular state (similar to 75 degrees C), we enter a free-flowing translucent coil phase (similar to 47 degrees C), then a turbid gel (similar to 25 degrees C) where the copolymer is collapsed in the HI phase, and finally a low-temperature clear gel (similar to 5 degrees C) where the copolymer is in the expanded coil state.

}, issn = {0024-9297}, doi = {10.1021/ma100357h}, author = {Jijo, V. J. and Sharma, Kamendra P. and Mathew, Renny and Kamble, Samruddhi and Rajamohanan, P. R. and Ajithkumar, Thalasseril G. and Badiger, Manohar V. and Kumaraswamy, Guruswamy} } @article { ISI:000283805600011, title = {Synthesis and characterization of thermo-sensitive graft copolymer of carboxymethyl guar and poly(N-isopropylacrylamide)}, journal = {Carbohydrate Polymers}, volume = {83}, number = {1}, year = {2011}, month = {JAN}, pages = {74-80}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Thermo-responsive graft copolymers of carboxymethyl guar [CMG] and semitelechelic poly(N-isopropylacrylamide) [PNIPAm] were synthesized by coupling reaction between them using a water-soluble coupling agent namely, 1-(3-(dimethylamino) propyl)-3-ethyl carbodiimide hydrochloride [EDC]. The incorporation of PNIPAm into CMG was confirmed by FT-IR and NMR spectroscopy. The graft copolymers, CMG-g-PNIPAm showed enhanced viscosity as compared to the unmodified CMG in the semi-dilute regime. Due to the presence of a LCST side chains [PNIPAm], the graft copolymers exhibited thermo-responsive nature with respect to temperature which was investigated using pyrene fluorescence probe studies. Although the thermo-responsive property was observed, the thermo-thickening behavior was not seen in these polymers. The graft copolymers in the semi-dilute regime (C(p) approximate to 10-20 g/L) showed viscoelastic properties and the relaxation time, tau, could be obtained from the crossover of frequency (oh) of storage modulus (G{\textquoteright}) and loss modulus (G {\textquoteleft}{\textquoteright}) in the oscillatory experiments. The activation energy {\textquoteleft}E(a){\textquoteright} of associations was investigated using the time temperature superpsition (TTS). These thermo-responsive polymers along with the biodegradability of CMG can have potential application as industrial thickening agent. (C) 2010 Elsevier Ltd. All rights reserved.

}, keywords = {Carboxymethyl guar, Poly(N-isopropylacrylamide), Thermo-sensitivity and graft copolymer}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2010.07.023}, author = {Gupta, Nivika R. and Ghute, Pallavi P. and Badiger, Manohar V.} } @article { ISI:000299775500022, title = {Controlled release of nutrients to mammalian cells cultured in shake flasks}, journal = {Biotechnology Progress}, volume = {28}, number = {1}, year = {2012}, month = {JAN}, pages = {188-195}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Though cell culture-based protein production processes are rarely carried out under batch mode of operation, cell line and initial process development operations are usually carried out in batch mode due to simplicity of operation in widely used scale down platforms like shake flasks. Nutrient feeding, if performed, is achieved by bolus addition of concentrated feed solution at different intervals, which leads to large transient increases in nutrient concentrations. One negative consequence is increased waste metabolite production. We have developed a hydrogel-based nutrient delivery system for continuous feeding of nutrients in scale down models like shake flasks without the need for manual feed additions or any additional infrastructure. Continuous delivery also enables maintaining nutrient concentrations at low levels, if desired. The authors demonstrate the use of these systems for continuous feeding of glucose and protein hydrolysate to a suspension Chinese Hamster Ovary (CHO) culture in a shake flask. Glucose feeding achieved using the glucose-loaded hydrogel resulted in a 23\% higher integral viable cell density and an 89\% lower lactate concentration at the end of the culture when compared with a bolus-feed of glucose. (c) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012

}, issn = {8756-7938}, doi = {10.1002/btpr.729}, author = {Hegde, Swati and Pant, Tejal and Pradhan, Ketaki and Badiger, Manohar V. and Gadgil, Mugdha} } @article { ISI:000312472000040, title = {Gold nanoparticle embedded hydrogel matrices as catalysts: better dispersibility of nanoparticles in the gel matrix upon addition of N-bromosuccinimide leading to increased catalytic efficiency}, journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects}, volume = {414}, year = {2012}, month = {NOV}, pages = {296-301}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple and convenient method for generating and immobilizing gold NPs into polyethylene glycol-polyurethane (PEGPU) matrices is presented. The gold NP immobilized PEGPU (Au NP-PEGPU) hydrogel matrices are easy to handle and can be used as catalysts. The efficiency, reusability and durability of the Au NP-PEGPU catalyst matrices were investigated using the reduction of 4-nitroaniline (4NA) to p-phenylenediamine (p-PDA) by sodium borohydride in the presence of the catalyst as a test reaction. The Au NPs in the PEGPU matrix got aggregated after 3 cycles of catalysis but dispersion could be regenerated by the addition of N-bromosuccinimide (NBS). After this regeneration process the Au NPs-PEGPU matrix showed excellent efficiency without any aggregation, leaching or degradation. The reusability of the catalyst for 28 cycles yielding a total turnover number of 3220 and turn over frequency of 0.152 s(-1) is demonstrated. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {catalysis, hydrogels, Immobilization, Nanoparticles, Turn over numbers}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2012.08.026}, author = {Ramtenki, Vilas and Anumon, V. D. and Badiger, Manohar V. and Bhagavatula L. V. Prasad} } @article { ISI:000329137400081, title = {Design of a high performance thin all-solid-state supercapacitor mimicking the active interface of its liquid-state counterpart}, journal = {ACS Applied Materials \& Interfaces}, volume = {5}, number = {24}, year = {2013}, month = {DEC}, pages = {13397-13404}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Here we report an all-solid-state supercapacitor (ASSP) which closely mimics the electrode-electrolyte interface of its liquid-state counterpart by impregnating polyaniline (PANO-coated carbon paper with polyvinyl alcohol-H2SO4 (PVA-H2SO4) gel/plasticized polymer electrolyte. The well penetrated PVA-H2SO4 network along the porous carbon matrix essentially enhanced the electrode-electrolyte interface of the resulting device with a very low equivalent series resistance (ESR) of 1 Omega/cm(2) and established an interfacial structure very similar to a liquid electrolyte. The designed interface of the device was confirmed by cross-sectional elemental mapping and scanning electron microscopy (SEM) images. The PANI in the device displayed a specific capacitance of 647 F/g with an areal capacitance of 1 F/cm(2) at 0.5 A/g and a capacitance retention of 62\% at 20 A/g. The above values are the highest among those reported for any solid-state-supercapacitor. The whole device, including the electrolyte, shows a capacitance of 12 F/g with a significantly low leakage current of 16 mu A(2). Apart from this, the device showed excellent stability for 10000 cycles with a coulombic efficiency of 100\%. Energy density of the PANI in the device is 14.3 Wh/kg.

}, keywords = {all-solid-state, cyclic voltametry, impedance analysis, polyaniline, polyvinyl alcohol, supercapacitor}, issn = {1944-8244}, doi = {10.1021/am404320e}, author = {Anothumakkool, Bihag and Torris, Arun A. T. and Bhange, Siddheshwar N. and Unni, SreeKuttan M. and Badiger, Manohar V. and Kurungot, Sreekumar} } @article { ISI:000318748300011, title = {Thermodynamic behavior of hydrophobically modified polyacrylamide containing random distribution of hydrophobes: experimental and theoretical investigations}, journal = {Polymer}, volume = {54}, number = {11}, year = {2013}, month = {MAY}, pages = {2676-2689}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Two series of Hydrophobically Modified Polyacrylamides (HMPAMs) were prepared by free radical copolymerization of trimethylsilylacrylamide with 3-pentadecylcyclohexylacrylamide (PDCAM) or dodecylacrylamide (DDAM) followed by removal of trimethylsilyl protecting groups. The solution properties of HMPAMs were studied in dilute aqueous solution by fluorescence spectroscopy, NMR and viscometry. The properties in aqueous solution of HMPAMs clearly displayed the formation of hydrophobic interactions between alkyl stickers. While dodecyl containing HMPAMs mainly showed a progressive collapse of the copolymer coil with the increasing fraction of hydrophobic moieties (weak intra-chain associations), pentadecylcyclohexyl groups containing HMPAMs exhibited a much lower solubility in water due to strong intra- and inter-chain associations. Experimental data were analyzed using the mean field theory developed by Semenov and Rubinstein (SR) for associating polymers. Using a set of realistic parameters, taking into account the solubility of the backbone, the fraction of stickers and the strength of hydrophobic attractions, we show that the SR model offers a quantitative description of the thermodynamic properties of HMPAMs in terms of individual and collective behavior of polymers chains; i.e. swelling and phase separation, respectively. (C) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Associating polymer, Polyacrylamide, Self-assembling}, issn = {0032-3861}, doi = {10.1016/j.polymer.2013.03.039}, author = {Hourdet, Dominique and Ducouret, Guylaine and Varghese, Sony and Badiger, Manohar V. and Wadgaonkar, Prakash P.} } @article {43040, title = {All-solid-state-supercapacitor and a process for the fabrication thereof}, number = {PCT/IN2014/000233}, year = {2014}, month = {OCT}, abstract = {

The present invention discloses. all-solid-state supercapacitor (ASSP) with enhanced electrode-electrolyte interface which gives highest very high specific capacitance, areal capacitance and shows very low internal resistance (ESR). The invention particularly discloses the fabrication of all-solid-state supercapacitor by intercalation of solid state polymer electrolyte inside the conducting porous substrate coated with a charge storage electrode material to achieve the desired effect.

}, author = {Kurungot, Sreekumar and Badiger, Manohar V. and Anothumakkool, Bihag and Torris, Arun} } @article { ISI:000336883000054, title = {Electrodeposited polyethylenedioxythiophene with infiltrated gel electrolyte interface: a close contest of an all-solid-state supercapacitor with its liquid-state counterpart}, journal = {Nanoscale}, volume = {6}, number = {11}, year = {2014}, month = {JUN}, pages = {5944-5952}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report the design of an all-solid-state supercapacitor, which has charge storage characteristics closely matching that of its liquid-state counterpart even under extreme temperature and humidity conditions. The prototype is made by electro-depositing polyethylenedioxythiophene (PEDOT) onto the individual carbon fibers of a porous carbon substrate followed by intercalating the matrix with polyvinyl alcohol-sulphuric acid (PVA-H2SO4) gel electrolyte. The electrodeposited layer of PEDOT maintained a flower-like growth pattern along the threads of each carbon fiber. This morphology and the alignment of PEDOT led to an enhanced surface area and electrical conductivity, and the pores in the system enabled effective intercalation of the polymer-gel electrolyte. Thus, the established electrode-electrolyte interface nearly mimics that of its counterpart based on the liquid electrolyte. Consequently, the solid device attained very low internal resistance (1.1 Omega cm(-2)) and a high specific capacitance (181 F g(-1)) for PEDOT at a discharge current density of 0.5 A g(-1). Even with a high areal capacitance of 836 mF cm(-2) and volumetric capacitance of 28 F cm(-3), the solid device retained a mass-specific capacitance of 111 F g(-1) for PEDOT. This is in close agreement with the value displayed by the corresponding liquid-state system (112 F g(-1)), which was fabricated by replacing the gel electrolyte with 0.5 M H2SO4. The device also showed excellent charge-discharge stability for 12 000 cycles at 5 A g(-1). The performance of the device was consistent even under wide-ranging humidity (30-80\%) and temperature (-10 to 80 degrees C) conditions. Finally, a device fabricated by increasing the electrode area four times was used to light an LED, which validated the scalability of the process.

}, issn = {2040-3364}, doi = {10.1039/c4nr00659c}, author = {Anothumakkool, Bihag and Torris, Arun A. T. and Bhange, Siddheshwar N. and Badiger, Manohar V. and Kurungot, Sreekumar} } @inbook {43343, title = {Hydrophobically Modified Chitosan}, booktitle = {Hydrophobically Modified Chitosan}, volume = {19}, year = {2014}, pages = {91-102}, chapter = {Advances in Planar Lipid Bilayers and Liposomes }, abstract = {

Hydrophobically modified chitosan was prepared using the hydrophobic compound derived from natural resource material such as cashew nut shell liquid. Chitosan was modified using 3-pentadecyl cyclohexane carbaldehyde to different extents (2, 3, and 5 mol\%). Solution properties of hydrophobically modified chitosan were studied by rheology and light scattering. These indicated the aggregation behavior above the critical association concentration. Further, it was concluded that above the critical association concentration, the dynamics of the network formed due to the associations slowed down significantly.

}, doi = {10.1016/B978-0-12-418699-6.00004-7}, author = {Shedge, Aarti S. and Badiger, Manohar V.} } @article { ISI:000332061300050, title = {Nanocomposite of silver and thermo-associating polymer by a green route: a potential soft-hard material for controlled drug release}, journal = {RSC Advances}, volume = {4}, number = {20}, year = {2014}, month = {JAN}, pages = {10261-10268}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Major research efforts are continuously being made to look for alternative, environment friendly green chemicals for the synthesis of nanoparticles in place of conventional and hazardous reducing agents such as sodium borohydride and hydrazine. We report here on the synthesis and characterization of AgNPs using a thermo-associating polymer namely, carboxymethyl guar grafted poly(ethylene oxide-co-propylene oxide) [CMG-g-PEPO]. The polymer acts as both reducing agent as well as stabilizing/capping agent. The formation of AgNPs with polymer was confirmed by UV/Vis spectroscopy and the TEM images indicated the size of nanoparticles to be in the range of 10-20 nm. We also demonstrated the use of these nanoparticles in the controlled release of doxorubicin hydrochloride (Dox), an anticancer drug. The binding of Dox onto the polymer and AgNPs was investigated by XPS and Raman spectroscopy which indicates that a charge-transfer mechanism is operative between the Dox and polymer holding both the entities together. The first synthesis of AgNPs using non-toxic thermo-associating polymer and subsequent release of Dox with body temperature (37 degrees C) as a trigger is the highlight of the present work.

}, issn = {2046-2069}, doi = {10.1039/c3ra45022h}, author = {Gupta, Nivika R. and Bhagavatula L. V. Prasad and Gopinath, Chinnakonda S. and Badiger, Manohar V.} } @article { ISI:000368141200024, title = {Drug-drug molecular salt hydrate of an anticancer drug gefitinib and a loop diuretic drug furosemide: an alternative for multidrug treatment}, journal = {Journal of Pharmaceutical Sciences}, volume = {104}, number = {12}, year = {2015}, month = {DEC}, pages = {4207-4216}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

A 1:1 monohydrate salt containing gefitinib, an orally administrated chemotherapy treatment for lung and breast cancers and furosemide, a loop diuretic drug, commonly used in the treatment of hypertension and edema, has been prepared. The molecular salt crystallized in triclinic P-1 space group. The CO bond lengths (similar to 1.26 angstrom) in the COOH group show that proton transfer has occurred from furosemide to morpholine moiety of the gefitinib suggesting cocrystal to be ionic. The morpholine moiety of the gefitinib showed significant conformational change because of its involvement in conformation dictating the strong N-H center dot center dot center dot O hydrogen bonding interaction. The strong hydrogen bonding interaction between gefitinib and furosemide places their benzene rings in stacking mode to facilitate the generation of pi-stack dimers. The neighboring dimers are bridged to each other via water molecule through N-H center dot center dot center dot O, C-H center dot center dot center dot O, O-H center dot center dot center dot N, and O-H center dot center dot center dot O interactions. The remarkable stability of the salt hydrate could be attributed to the strong hydrogen bonding interactions in the crystal structure. Interestingly, release of water from the lattice at 140 degrees C produced new anhydrous salt that has better solubility and dissolution rate than salt hydrate. The drug-drug molecular salt may have some bearing on the treatment of patient suffering from anticancer and hypertension. (C) 2015 Wiley Periodicals, Inc. and the American Pharmacists Association

}, keywords = {cancer chemotherapy, cocrystals, crystal engineering, crystal structure, dissolution rate, hydrate, phase transition, solubility, stability, thermal analysis}, issn = {0022-3549}, doi = {10.1002/jps.24651}, author = {Thorat, Shridhar H. and Sahu, Sanjay Kumar and Patwadkar, Manjusha V. and Badiger, Manohar V. and Gonnade, Rajesh G.} } @article { ISI:000347609400069, title = {Efficient Ag-nanoparticle embedded semi-IPN hydrogel for catalytic applications}, journal = {RSC Advances}, volume = {5}, number = {10}, year = {2015}, month = {DEC}, pages = {7567-7574}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Silver nanoparticle embedded semi-IPN hydrogels based on a combination of poly(acrylamide) and poly(aspartic acid) were synthesized. These semi-IPN hydrogel networks can potentially serve as micro or nano reactors for entrapment of metal nanoparticles. Current methodology allows us to entrap metal nanoparticles throughout hydrogel networks via poly(aspartic acid) chains which are dispersed homogeneously in the gel matrix. The Ag-NPs were characterized by UV-vis absorption spectroscopy, transmission electronic microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX). The Ag embedded hydrogels catalyze the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 very efficiently at room temperature with good recyclability upto 3 cycles.

}, issn = {2046-2069}, doi = {10.1039/c4ra14594a}, author = {Patwadkar, Manjusha V. and Gopinath, Chinnakonda S. and Badiger, Manohar V.} } @article { ISI:000351556100059, title = {Polyelectrolytes in dilute solution: viscometric access to coil dimensions and salt effects}, journal = {RSC Advances}, volume = {5}, number = {35}, year = {2015}, month = {MAR}, pages = {27674-27681}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Copolymers of acrylamide (AM) and diallyldimethylammonium chloride (DADMAC), differing in molar masses M (52.3 to 227 kDa) and degrees of charging y (0.2 to 0.6), were studied with respect to their viscometric behavior in dilute aqueous solutions containing variable amounts of NaCl. Complementary measurements were performed on a Brookhaven 90 plus particle size analyzer. M dominates the intrinsic viscosities [eta]. For the viscometric interaction parameters B this is only true for large concentrations of extra salt. [eta] and B as a function of solvent salinity follow Boltzmann laws. Coil dimensions, determined either via dynamic light scattering or viscometry, agree well. For low salt contents of the solvent the radii decrease with rising polymer concentration, whereas they increase for high salt concentrations; at a characteristic salinity of the solvent they become independent. Zeta potentials grow from +20 to +40 mV as y goes up.

}, issn = {2046-2069}, doi = {10.1039/c5ra01376c}, author = {Suresha, P. R. and Badiger, Manohar V. and Wolf, Bernhard A.} } @article { ISI:000349401200010, title = {Porous poly(ethylene glycol)-polyurethane hydrogels as potential biomaterials}, journal = {Polymer International}, volume = {64}, number = {3}, year = {2015}, month = {MAR}, pages = {397-404}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

We report the synthesis of porous poly(ethylene glycol)-polyurethane (PEG-PU) hydrogels using PEG-4000 as a soft segment and 4,4-methylenebis(cyclohexylisocyanate) as a hard segment. The degree of swelling in the hydrogels could be controlled by varying the amount of crosslinking agent, namely 1,2,6-hexanetriol. Structural characterization of the hydrogels was performed using solid-state C-13 NMR and Fourier transform infrared spectroscopy. Wide-angle X-ray diffraction studies revealed the existence of crystalline domains of PEG and small-angle X-ray scattering studies showed the presence of lamellar microstructures. For generating a porous structure in the hydrogels, cryogenic treatment with lyophilization was used. Scanning electron microscopy and three-dimensional micro-computed tomography imaging of the hydrogels indicated the presence of interconnected pores. The mechanical strength of the hydrogels and xerogels was measured using dynamic mechanical analysis. The observed dynamic storage moduli (E) for the equilibrium swollen and dry gels were found to be 0.15 and 4.2 MPa, respectively. Interestingly, the porous PEG-PU xerogel also showed E of 5.6 MPa indicating a similar mechanical strength upon incorporating porosity into the gel matrix. Finally, preliminary cytocompatibility studies showed the ability of cells to proliferate in the hydrogels. These gels show promise for applications as scaffolds and implants in tissue engineering. (c) 2014 Society of Chemical Industry

}, keywords = {hydrogels, permeability, poly(ethylene glycol), polyurethane, porosity}, issn = {0959-8103}, doi = {10.1002/pi.4802}, author = {Divakaran, Anumon V. and Torris, Arun A. T. and Lele, Ashish K. and Badiger, Manohar V.} } @article { ISI:000346263800042, title = {Synthesis and characterization of PEPO grafted carboxymethyl guar and carboxymethyl tamarind as new thermo-associating polymers}, journal = {Carbohydrate Polymers}, volume = {117}, year = {2015}, month = {MAR}, pages = {331-338}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

New thermo associating polymers were designed and synthesized by grafting amino terminated poly(ethylene oxide-co-propylene oxide) (PEPO) onto carboxymethyl guar (CMG) and carboxymethyl tamarind (CMT). The grafting was performed by coupling reaction between-NH2 groups of PEPO and -COOH groups of CMG and CMT using water-soluble EDC/NHS as coupling agents. The grafting efficiency and the temperature of thermo-association, T-assoc in the copolymer were studied by NMR spectroscopy. The graft copolymers, CMG-g-PEPO and CMT-g-PEPO exhibited interesting thermo-associating behavior which was evidenced by the detailed rheological and fluorescence measurements. The visco-elastic properties (storage modulus, G{\textquoteright}; loss modulus, G{\textquoteright}{\textquoteright}) of the copolymer solutions were investigated using oscillatory shear experiments. The influence of salt and surfactant on the T-assoc was also studied by rheology, where the phenomenon of {\textquoteleft}{\textquoteleft}Salting out{\textquoteright}{\textquoteright} and {\textquoteleft}{\textquoteleft}Salting in{\textquoteright}{\textquoteright} was observed for salt and surfactant, respectively, which can give an easy access to tunable properties of these copolymers. These thermo-associating polymers with biodegradable nature of CMG and CMT can have potential applications as smart injectables in controlled release technology and as thickeners in cosmetics and pharmaceutical formulations. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {Carboxymethyl guar, Carboxymethyl tamarind, Pluronics, Rheology, Solution behavior, Thermo-associating polymers}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2014.09.073}, author = {Gupta, Nivika R. and Torris, Arun A. T. and Wadgaonkar, Prakash P. and Rajamohanan, P. R. and Ducouret, Guylaine and Hourdet, Dominique and Creton, Costantino and Badiger, Manohar V.} } @article {43036, title = {Enhanced drug release by selective cleavage of cross-links in a double-cross-linked hydrogel}, journal = {RSC Advances}, volume = {6}, year = {2016}, month = {OCT}, pages = {102453-102461}, abstract = {

In the present paper, we report on the synthesis and characterization of redox sensitive double-cross-linked poly(acrylic acid) hydrogels using two different cross-linking agents, Jeffamine (R) and cystamine. The amount of two cross-linking agents was varied in order to synthesize hydrogels with different mechanical strengths. Jeffamine provides mechanical stability to the hydrogels while cystamine incorporates redox sensitivity. The stress values at the break point of the mono-and double-crosslinked hydrogels were determined from stress-strain plots. The disulphide bonds (S-S) in the cystamine were cleaved selectively in the presence of dithiothreitol, which increased the degree of hydrogel swelling. This phenomenon of in situ breaking of one cross-linking and increasing the swelling ratio could be used in swelling-controlled drug delivery systems. The implication of selective breaking of cross-links on the swelling-controlled release of the anticancer drug doxorubicin was demonstrated. We also successfully prepared Ag nanoparticles in the dual cross-linked hydrogels in order to incorporate antibacterial properties and studied their release by selective cleavage of cystamine bonds. These double-cross-linked hydrogels show great promise in drug delivery and tissue engineering applications.

}, doi = {10.1039/c6ra19443e}, author = {Tiwari, Neha and Badiger, Manohar V.} } @article { ISI:000368651100021, title = {High-Performance flexible solid-state supercapacitor with an extended nanoregime interface through in situ polymer electrolyte generation}, journal = {ACS Applied Materials \& Interfaces}, volume = {8}, number = {2}, year = {2016}, month = {JAN}, pages = {1233-1241}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{Here, we report an efficient strategy by which a significantly enhanced electrodeelectrolyte interface in an electrode for supercapacitor application could be accomplished by allowing in situ polymer gel electrolyte generation inside the nanopores of the electrodes. This unique and highly efficient strategy could be conceived by judiciously maintaining ultraviolet-triggered polymerization of a monomer mixture in the presence of a high-surface-area porous carbon. The method is very simple and scalable, and a prototype, flexible solid-state supercapacitor could even be demonstrated in an encapsulation-free condition by using the commercial-grade electrodes (thickness = 150 mu m

}, keywords = {cyclic voltametry, impedance analysis, in situ polymer generation, interface, polymer electrolyte, supercapacitor}, issn = {1944-8244}, doi = {10.1021/acsami.5b09677}, author = {Anothumakkool, Bihag and Torris, Arun A. T. and Veeliyath, Sajna and Vijayakumar, Vidyanand and Badiger, Manohar V. and Kurungot, Sreekumar} } @article { ISI:000374196000022, title = {Mechanically tunable curcumin incorporated polyurethane hydrogels as potential biomaterials}, journal = {Chemistry of Materials}, volume = {28}, number = {7}, year = {2016}, month = {APR}, pages = {2120-2130}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We report here on the one-pot synthesis and characterization of curcumin incorporated polyethylene glycol polyurethane (PU-CUR) hydrogels using PEG-4000, 4, 4{\textquoteright}-methylenebis (cyclohexyl isocyanate), curcumin in the presence of a cross-linker, 1,2,6 hexanetriol (HT). Besides the physical entrapment, curcumin also provides a partial cross linking in the 3-D structure of the hydrogel. The degree of swelling in hydrogels could be controlled by varying the amount of HT as well as curcumin. The structural characterization of hydrogels was performed using Fourier transform infrared spectroscopy, high-resolution mass spectrometry, UV and fluorescence spectroscopy. The wide-angle X-ray scattering studies revealed the existence of crystalline domains of PEG, and the small-angle X-ray scattering studies showed the presence of lamellar microstructures. Porous structure in the hydrogel was created by cryogenic treatment and lyophilization. Scanning electron microscopy and microcomputed tomography imaging of hydrogels showed the presence of interconnected pores. The mechanical strength of the hydrogels was measured using a universal testing machine. The observed tensile and breaking compression strengths for the equilibrium swollen gels were found to be in the range of 0.22-0.73 MPa and 1.65-4.6 MPa, respectively. Detailed in vitro biological experiments showed the biocompatibility of gels, cytostatic dosage of curcumin, selective toxicity toward cancer cell lines, and antibacterial property. These gels show promising applications as scaffolds and implants in tissue engineering.

}, issn = {0897-4756}, doi = {10.1021/acs.chemmater.5b04964}, author = {Divakaran, Anumon V. and Azad, Lal Busher and Surwase, Sachin S. and Torris, Arun A. T. and Badiger, Manohar V.} } @article {43038, title = {Product distribution in hydrogenation of styrene oxide over Pd/chitosan catalyst}, journal = {Research on Chemical Intermediates}, volume = {42}, year = {2016}, month = {OCT}, pages = {7581-7595}, abstract = {

Palladium-decorated chitosan catalyst was synthesized by an impregnation method by varying the Pd loading in the range of 1-6 \%, and was evaluated for the regioselective hydrogenation of styrene oxide. In order to correlate the chemical and textural properties with the catalytic activity, all the prepared catalysts were characterized by techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron spectroscopy, thermo-gravimetric analysis, temperature-programmed desorption of NH3, and CO2 and N-2 physisorption. The synthesized catalysts were utilized for the efficient and regioselective ring opening of styrene oxide by hydrogenation under different conditions. The complete conversion of styrene oxide with 65 \% selectivity for 2-phenyl ethanol and 33 \% for 1-phenyl ethanol were obtained using 4 \% Pd/CS catalyst at 70 degrees C temperature and 3 MPa pressure. The mechanism for the regio selective ring opening of styrene oxide to 1- and 2-phenyl ethanol was also proposed on the basis of properties of the catalyst support, catalytic activity and selectivity. These results indicated that the catalytic activity and selectivity of the catalysts were affected by the nature of support. Further, the basic properties of the support play an important role in the selectivity of the styrene oxide hydrogenation reaction.

}, doi = {10.1007/s11164-016-2554-3}, author = {Viswanadhan, Maya and Potdar, Aparna and Divakaran, Anumon V. and Badiger, Manohar V. and Rode, Chandrashekhar} } @article { ISI:000370489600002, title = {Role of aliphatic hydrocarbon content in non-solvating porogens toward porosity of cross-linked microbeads}, journal = {Polymer}, volume = {86}, year = {2016}, month = {MAR}, pages = {8-14}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Megaporous spherical acrylate copolymer beads were synthesized by suspension polymerization using non-solvating porogens. Non-solvating porogens with higher aliphatic hydrocarbon content generated megaporous morphology with lower surface area. Surface area increased and inversely megaporosity was decreased with decrease in the aliphatic hydrocarbon content of porogen. Megaporosity (5.47 mu m) and pore volume of 5.52 cm(3)/g was obtained with n-decanol. Thermal property of copolymer is a function of type (rigidity/flexibility/elemental composition) and concentration (cross-link density) of monomer and cross-linker. Copolymer containing rigid cross-linker (divinylbenzene) had better thermal stability over copolymer with flexible cross-linker (ethylene dimethacrylate). Further, higher concentration of rigid cross-linker or lower concentration of flexible cross-linker enhanced the thermal stability. Porous polymers are potentially recognized as a solid support for solid-phase synthesis. (C) 2016 Elsevier Ltd. All rights reserved.

}, keywords = {Cross-linked microbeads, Interfacial tension, Megaporosity, Non-solvating porogens, Thermal properties}, issn = {0032-3861}, doi = {10.1016/j.polymer.2016.01.022}, author = {Mane, Sachin and Badiger, Manohar V. and Rajan, C. R. and Ponrathnam, Surendra and Chavan, Nayaku} } @article { ISI:000369001500017, title = {Toughening of epoxy novolac resin using cardanol based flexibilizers}, journal = {Journal of Applied Polymer Science}, volume = {133}, number = {16}, year = {2016}, month = {APR}, pages = {43318}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

In this work, two different cardanol based epoxies (Cardolite NC-514 and Cardanol NC-547) were employed as flexibilizers to toughen an epoxy novolac resin namely, poly[(phenylglycidyl ether)-co-formaldehyde] (PPGEF). 4,4-Diamino-3,3-dimethyl dicyclohexyl methane (BMCHA) was used as a curing agent. Differential scanning calorimetry and dynamic mechanical thermal analysis of the composites showed a gradual decrease in glass transition temperatures (T-g) with increase in cardolite content confirming the incorporation of flexible moieties into the brittle resin matrix. Improvement in toughening of PPGEF/Cardolite composites was manifested by increase in the izod impact strength of both the composites. The tensile strength increased marginally for composites with increasing amount of Cardolite NC-514 but decreased for the composites containing Cardolite NC-547. This was attributed to the lack of rotational motion in the chain due to close proximity of rigid phenyl rings in NC-547. SEM of the cryo-fractured surfaces of composites showed good compatibility between PPGEF and cardanol based flexibilizers. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43318.

}, keywords = {composites, crosslinking, glass transition}, issn = {0021-8995}, doi = {10.1002/app.43318}, author = {Gour, Rajeshwari S. and Kodgire, Vivek V. and Badiger, Manohar V.} } @article {43340, title = {Carboxymethyl cellulose-grafted mesoporous silica hybrid nanogels for enhanced cellular uptake and release of curcumin}, journal = {Gels}, volume = {3}, year = {2017}, month = {FEB}, abstract = {

Mesoporous silica nanoparticles (MSNs) with ordered pore structure have beensynthesized and used as carriers for the anticancer drug curcumin. MSNs were functionalizedwith amine groups and further attached with carboxymethyl cellulose (CMC) using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) coupling chemistry, which increased the hydrophilicityand biocompatibility of MSNs. The functionalized MSNs (MSN-NH2and MSN-CMC) werecharacterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM),Dynamic Light Scattering (DLS), N2adsorption, X-Ray Diffraction (XRD), Thermo GravimetricAnalysis (TGA) and Fourier Transform Infrared Spectroscopy (FT-IR). Thein vitrorelease of curcuminfrom the {\textendash}NH2and CMC functionalized MSNs (MSN-cur-NH2and MSN-cur-CMC) was performedin 0.5\% aqueous solution of sodium lauryl sulphate (SLS). The effect of CMC functionalization ofMSNs towards cellular uptake was studied in the human breast cancer cell line MDA-MB-231 andwas compared with that of MSN-NH2and free curcumin (cur). Both MSN-NH2and MSN-CMCshowed good biocompatibility with the breast cancer cell line. The MTT assay study revealedthat curcumin-loaded MSN-cur-CMC showed better uptake as compared to curcumin-loadedMSN-cur-NH2. Free curcumin was used as a control and was shown to have much less internalizationas compared to the curcumin-loaded functionalized MSNs due to poor bioavailability. Fluorescencemicroscopy was used to localize the fluorescent drug curcumin inside the cells. The workdemonstrates that CMC-functionalized MSNs can be used as potential carriers for loading and releaseof hydrophobic drugs that otherwise cannot be used effectively in their free form for cancer therapy.

}, doi = {10.3390/gels3010008}, author = {Tiwari, Neha and Nawale, Laxman U. and Sarkar, Dhiman and Badiger, Manohar V.} } @article {43806, title = { Design and development of trivalent aluminum ions induced self healing polyacrylic acid novel hydrogels}, journal = {POLYMER}, volume = {126}, year = {2017}, month = {SEP}, pages = { 196-205}, type = {Journal Article}, chapter = {196-205}, abstract = {

Development of ionically crosslinked superabsorbent polyacrylic acid (PAA) self-healing hydrogels using trivalent aluminum ions was investigated. The PAA hydrogels exhibited excellent self-healing behavior depending on the amount of the aluminum within the matrix. The migration of these ions within the polymer matrix was responsible for the physical crosslinking of the hydrogel and the origin of self healing ability. The PAA-Al hydrogels were insoluble in water and exhibited significantly high degree of swelling (similar to 4000\%). Hydrogel also exhibited good mechanical properties with high level of elongation. Excellent self-healing efficiency was observed under dynamic as well as oscillatory Theological measurements. The presence of Al ions within PAA hydrogel facilitated the self-healing ability because of the ionic interaction in these gels which plays the key role of dynamic reversible sacrificial bonds which reforms upon reversal of the deformative force. (C) 2017 Elsevier Ltd. All rights reserved.

}, keywords = {Aluminum chloride, Behavior, Complex, Composite, crosslinking, Delivery, High-Mechanical Strength, hydrogels, Network, Polyacrylic acid, Polymeric Materials, Self-healing, swelling, Tough; pH}, issn = {0032-3861}, doi = {10.1016/j.polymer.2017.08.045}, author = {Anjum, Sadiya and Gurave, Pramod and Badiger, Manohar V. and Tiwari, Neha and Gupta, Bhuvanesh} } @article {43341, title = {Flexible epoxy novolac coatings: use of cardanol-based flexibilizers}, journal = {Journal of Applied Polymer Science}, year = {2017}, month = {FEB}, abstract = {Flexible epoxy novolac coatings were developed by reacting an epoxy novolac resin, Poly[(phenylglycidyl ether)-co-formaldehyde] (PPGEF) with an amine curing agent, 4,4'-diamino-3,3'-dimethyldicyclohexyl methane (BMCHA), cardanol based reactive diluent (Cardolite NC-513) and two different cardanol-based flexibilizers (Cardolite NC-514 and Cardolite NC-547). The flexibilizer content was varied from 5 to 10\% by weight of the resin. These resins were coated onto the stainless steel panels and tested for their gloss, cross-hatch adhesion, falling weight impact resistance, flexibility, abrasion, scratch hardness, solvent scrub resistance, and chemical resistance. The thermo-mechanical properties of these coatings were determined by TGA, DSC, DMTA, and tensile strength measurements. The cryofractured specimens were subjected to SEM analysis. The influence of structural differences of two flexibilizers on the coating properties was investigated. These coatings exhibited excellent properties and have great potential in industrial applications. {\textcopyright} 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44920.}, doi = {10.1002/app.44920}, author = {Gour, Rajeshwari S. and Raut, Kundalik G. and Badiger, Manohar V.} } @article {43938, title = {Optimization for the production of mycelial biomass from Benjaminiella poitrasii to isolate highly deacetylated chitosan}, journal = {Journal of Polymer Materials}, volume = {34}, year = {2017}, month = {MAR}, pages = {145-156}, type = {Article}, abstract = {

Benjaminiella poitrasii, a dimorphic zygomycetous fungus contains more chitosan in the mycelial cell wall than the cell wall of its yeast form. The optimized medium containing yeast extract, peptone, MgSO4, KH2PO4, trace metals (Fe2+, Mn2+ Zn2+ and Co2+ ) solution and 1\% starch produced 10-12 g/L(dry wt.) of mycelial biomass in 48 h in a 2L fermenter. Using 1N NaOH treatment from 1 g of dried biomass 51.00 {\textpm} 0.52 mg of chitosan of 42.82 KDa molecular weight and 94.24 \% degree of deacetylation was extracted. With Metarhizium anisopliae chitin deacetylase (CDA), chitosan yield was 59.00 {\textpm} 0.84 mg while treatment with CDA of B. poitrasii it was 78.05 {\textpm} 0.58 mg/g of dry wt. of biomass. The chitosan dissolved in 2\% acetic acid showed higher antifungal activity against Candida albicans (MIC90 0.025 mg/mL) and Candida glabrata (MIC90 0.2 mg/mL) than chitosan extracted from marine source (MIC90 \>1.6 mg/mL) suggesting use of fungal chitosan in healthcare.

}, author = {Mane, S. R. and Pathan, Ejaj K. and Kale, D. and Ghormade, Vandana and Gadre, Ramchandra V. and Rajamohanan, Pattuparambil Ramanpillai and Badiger, Manohar V. and Deshpande, Mukund V.} } @article {43342, title = {Thermo-reversible sol-gel transition of aqueous solutions of patchy polymers}, journal = {RSC Advances}, volume = {7}, year = {2017}, month = {JAN}, pages = {5101-5110}, abstract = {While aqueous solutions of several amphiphilic thermo-reversible polymers show gelation upon heating, there are fewer examples of polymer solutions that exhibit gelation when cooled. This paper reports an interesting phenomenon of abrupt thermoreversible gelation of aqueous solutions of a hydrophobically modified polymer upon cooling. A high molecular weight precursor copolymer (PCP, (M-w) over bar approximate to 5 x 10(6) g mol(-1)) of N, N-dimethylacrylamide (70 mol\%) and acrylic acid (30 mol\%) was modified by reacting 10 mol\% of the acrylic acid groups with n-dodecyl amine to form a hydrophobically modified copolymer (HMCP). The composition of the copolymer was ascertained using NMR spectroscopy. Cooling the solution of PCP at a controlled rate resulted in a gradual increase in its low shear viscosity as dictated by the flow activation energy. In contrast, cooling the solution of HMCP under identical conditions resulted in an abrupt and large non-Arrhenius increase in viscosity at a specific transition temperature, which decreased with decrease in polymer concentration. Fluorescence measurements and dynamic light scattering data showed that abrupt gelation happened upon cooling, when polymer coils percolate accompanied with concomitant transition in chain conformation from compact micellar coils formed by intra-chain hydrophobic associations to swollen polymer coils connected by inter-chain hydrophobic interactions.}, doi = {10.1039/c6ra27030a}, author = {Parmar, Indravadan A. and Shedge, Aarti S. and Badiger, Manohar V. and Wadgaonkar, Prakash P. and Lele, Ashish K.} } @article {44200, title = {Electrospinning of non-ionic cellulose ethers/polyvinyl alcohol nanofibers: characterization and applications}, journal = {Carbohydrate Polymers}, volume = {181}, year = {2018}, month = {FEB }, pages = {175-182}, type = {Article}, abstract = {

The morphology of spin-coated films and electrospun fibers of ethyl hydroxy ethyl cellulose (EHEC), hydrophobically modified ethyl hydroxy ethyl cellulose (HM-EHEC) and their blends with Poly(vinyl alcohol) (PVA) was examined by AFM, SEM and contact angle measurements. These polysaccharides upon blending with PVA exhibited smooth surface which was evidenced by Atomic Force Microscopy (AFM) observation. The electrospinnability of above polysaccharides with PVA was demonstrated for the first time. The oriented fibers could be obtained using a rotating disc collector. Contact angles of spin-coated films and electrospun fibers were discussed in terms of hydrophobicity and wetting characteristics. Further, The nanofibers of EHEC/PVA were in-situ crosslinked using citric acid and were used for controlled release of an antibacterial drug, Chlorhexidine Digluconate (ChD). In-vitro studies of cytotoxicity, cell growth and cell proliferation were performed using L929 mouse fibroblast cells. These nanofiber mats show potential in drug delivery and as scaffolds in tissue engineering applications.

}, keywords = {cellulose, drug delivery, electrospinning, Ethyl hydroxy ethyl cellulose, Hydrophobically modified ethyl hydroxy ethyl, scaffold, Spin coating}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2017.10.070}, author = {Wali, Ashwini and Zhang, Yucheng and Sengupta, Poulomi and Higaki, Yuji and Takahara, Atsushi and Badiger, Manohar V.} } @article {44516, title = {Mechanism of the formation of microphase separated water clusters in a water-mediated physical network of perfluoropolyether tetraol}, journal = {Soft Matter}, volume = {14}, year = {2018}, month = {MAR}, pages = {2339-2345}, abstract = {

Perfluoropolyether tetraol (PFPE tetraol) possesses a hydrophobic perfluoropolyether chain in the backbone and two hydroxyl groups at each chain terminal, which facilitates the formation of hydrogen bonds with water molecules resulting in the formation an extended physical network. About 3 wt\% water was required for the formation of the microphase separated physical network of PFPE tetraol. The mechanism responsible for the microphase separation of water clusters in the physical network was studied using a combination of techniques such as NMR spectroscopy, molecular dynamics (MD) simulations and DSC. MD simulation studies provided evidence for the formation of clusters in the PFPE tetraol physical network and the size of these clusters increased gradually with an increase in the extent of hydration. Both MD simulations and NMR spectroscopy studies revealed that these clusters position themselves away from the hydrophobic backbone or vice versa. The presence of intra-and inter-chain aggregation possibility among hydrophilic groups was evident. DSC results demonstrated the presence of tightly and loosely bound water molecules to the terminal hydroxyl groups of PFPE tetraol through hydrogen bonding. The data from all the three techniques established the formation of a physical network driven by hydrogen bonding between the hydrophilic end groups of PFPE tetraol and water molecules. The flexible nature of the PFPE tetraol backbone and its low solubility parameter favour clustering of water molecules at the terminal groups and result in the formation of a gel.

}, issn = {1744-683X}, doi = {10.1039/c7sm02181j}, author = {Deshpande, Ashwini A. and Torris, Arun A. T. and Pahari, Swagata and Menon, Shamal K. and Badiger, Manohar V. and Rajamohanan, P. R. and Wadgaonkar, Prakash P. and Roy, Sudip and Tonelli, Claudio} } @article {44480, title = {Thermo thickening behavior of MPEG-b-PCL grafted poly(acrylic acid): a molecular insight}, journal = {Polymer}, volume = {148}, year = {2018}, month = {JUL}, pages = {138-148}, type = {Journal Article}, abstract = {

We report on the synthesis and characterization of a new thermothickening polymer (PAA-g-(MPEG-b-PCL)) based on the grafting of a block copolymer of mono methoxy poly (ethylene glycol){\textendash}b-poly (caprolactone) (MPEG-b-PCL) onto poly (acrylic acid) (PAA). Rheological experiments reveal that aqueous solutions of PAA-g-(MPEG-b-PCL) exhibit interesting irreversible thermothickening behavior above a certain polymer concentration and critical temperature. Light scattering experiments show that increasing temperature induces hydrophobic associations and subsequent aggregation leading to gel formation which is irreversible. The mechanism of thermo thickening was examined at the molecular level by NMR methods which indicated unassembled and assembled environments of the MPEG-b-PCL grafts. On heating, interactions between the graft side chains are significantly enhanced and molecular mobility in the assembled microdomains is reduced. The stable well ordered microdomains that are formed on heating are retained on cooling thus, leading to irreversible gelation.

}, keywords = {Hydrophobically modified poly (acrylic acid), Light scattering, Methoxy polyethylene glycol-b-polycaprolactone (MPEG-b-PCL) copolymer, Rheology, Thermo gelation}, issn = {323861}, doi = {10.1016/j.polymer.2018.06.031}, author = {Tiwari, Neha}, editor = {Shedge, Aarti} } @article {45449, title = {Water-in-acid gel polymer electrolyte realized through a phosphoric acid-enriched polyelectrolyte matrix toward solid-state supercapacitors}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {6}, year = {2018}, month = {OCT}, pages = {12630-12640}, type = {Article}, abstract = {A new concept of water-in-acid gel polymer electrolytes (GPEs) is introduced. The simple and scalable UV-light-assisted synthesis of a copolymer matrix possessing polyelectrolyte behavior, followed by swelling in minimally diluted H3PO4 (15.1 M/88 wt \% aqueous solution), effects formation of a high proton-conducting, self-standing, and mechanically stable polyelectrolyte GPE (PGPE). Retention of high mechanical stability despite the presence of a large amount of liquid species makes it a promising candidate for replacing conventional GPEs. The high proton conductivity (9.8 X 10(-2) S cm(-1)) of the PGPE at an ambient temperature of 303 K is attributed to the high concentration of the conducting species present in the polymer matrix. The PGPE-based polyaniline (PANI) supercapacitor device (PANI-1) with a mass loading of 1 mg cm(-2) exhibits a high specific gravimetric capacitance of 385 F g(-1) at a current density of 0.25 mA cm(-2). At the same current density, the PANI-5 device retains high gravimetric and areal capacitance values of 258 F g(-1) and 1288 mF cm(-2), respectively. The low equivalent series resistance value of 0.78 Omega (for the PANI-5 device) further proves the excellent electrode-electrolyte interface formed by the water-in-acid GPE. A 100\% capacitance retention even after 9000 continuous charge-discharge cycles strongly indicates the feasibility of adopting water-in-acid GPEs in future supercapacitors.}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.8b01175}, author = {Vijayakumar, Vidyanand and Ghosh, Meena and Torris, Arun A. T. and Chandran, Nikhil M. K. and Nair, Sanoop B. and Badiger, Manohar V. and Kurungot, Sreekumar} } @article {45475, title = {Flocculation of kaolin from aqueous suspension using low dosages of acrylamide-based cationic flocculants}, journal = {Journal of Applied Polymer Science}, volume = {136}, year = {2019}, month = {APR}, pages = {Article Number: 47286}, type = {Article}, abstract = {

Flocculation of kaolin from aqueous streams has become very important in view of its wide range of applications. In this work, cationic flocculants based on copolymers of acrylamide (AM) and 3-acrylamidopropyltrimethylammonium chloride (APTMAC) were synthesized with two different mole ratios of monomers, 80 mol \% of AM (CP-8020) and 40 mol \% of AM (CP-4060). The chemical structures of copolymers were confirmed by H-1 and carbon-13 nuclear magnetic resonance (C-13 NMR) spectroscopy. The molecular weight (MW) and zeta potential of the copolymers were determined. High MW was obtained for copolymer with high content of AM (CP-8020) and high zeta potential was observed for copolymer with high content of APTMAC (CP-4060). Flocculation of kaolin suspension was performed using both CP-8020 and CP-4060 and the flocculation was correlated to the zeta potential and MW of the copolymers. The optimum dosages of flocculants were determined. The mechanism of flocculation was discussed in terms of charge neutralization and bridging. The flocs of kaolin were characterized in terms of moisture content and size. To the best of our knowledge, this copolymer system was used for the first time for kaolin flocculation and found out to be efficient. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47286.

}, keywords = {copolymers, hydrophilic polymers, polyelectrolytes}, issn = {0021-8995}, doi = {10.1002/app.47286}, author = {Suresha, P. R. and Badiger, Manohar V.} } @article {46216, title = { Polysaccharide hydrogel incorporated carbon nanofiber microelectrode for designing neural interfaces }, journal = {Journal of Bionic Engineering}, volume = {16}, year = {2019}, month = {JULY}, pages = {696-710}, type = {Article}, abstract = {

Bionic devices are an integral part of human life, and continuous innovations in their design and functions with the help of nanotechnology has revolutionized the area of neuroscience and technology. Bio-interfaces play a key role in bionic devices such as neural implants for efficient transfer of the signal to smart prosthetics. We report here on the design of a new microelectrode, comprising Carbon Nanofiber (CNF) and a biopolymer, namely carboxymethyl xyloglucan (CMX) hydrogel inside the CNF, which enhances the current density across the interface. Microelectrode was prepared by in-situ cross-linking of CMX inside CNF, with optimized CMX: CNF ratio, resulting in continuous ionic channels confined within the hollow core of CNF. Electron microscopy images of microelectrodes illustrate the formation of CMX hydrogel network inside the CNF hollow core without wrapping its surface. The presence of hydrogel in the CNF was confirmed by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). The electrochemical studies indicate the enhancement in charge density as well as the active surface area of the microelectrodes due to the presence of CMX hydrogel network. These microelectrodes have great potential as neural interfaces for designing smart prosthetics with voluntary control.

}, doi = {10.1007/s42235-019-0056-x}, author = {Torris, Arun and Badiger, Manohar V.} } @article {46077, title = {Self-assemblies of nucleolipid supramolecular synthons show unique self-sorting and cooperative assembling process}, journal = {Nanoscale}, volume = {11}, year = {2019}, month = {JUN }, pages = {11956-11966}, type = {Article}, abstract = {

The inherent control of the self-sorting and co-assembling process that has evolved in multi-component biological systems is not easy to emulate in vitro using synthetic supramolecular synthons. Here, using the basic component of nucleic acids and lipids, we describe a simple platform to build hierarchical assemblies of two component systems, which show an interesting self-sorting and co-assembling behavior. The assembling systems are made of a combination of amphiphilic purine and pyrimidine ribonucleoside-fatty acid conjugates (nucleolipids), which were prepared by coupling fatty acid acyl chains of different lengths at the 2 {\textquoteleft}-O- and 3 {\textquoteleft}-O-positions of the ribose sugar. Individually, the purine and pyrimidine nucleolipids adopt a distinct morphology, which either supports or does not support the gelation process. Interestingly, due to the subtle difference in the order of formation and stability of individual assemblies, different mixtures of supramolecular synthons and complementary ribonucleosides exhibit a cooperative and disruptive self-sorting and co-assembling behavior. A systematic morphological analysis combined with single crystal X-ray crystallography, powder X-ray diffraction (PXRD), NMR, CD, rheological and 3D X-ray microtomography studies provided insights into the mechanism of the self-sorting and co-assembling process. Taken together, this approach has enabled the construction of assemblies with unique higher ordered architectures and gels with remarkably enhanced mechanical strength that cannot be derived from the respective single component systems.

}, issn = {2040-3364}, doi = {10.1039/c9nr01863h}, author = {Nuthanakanti, Ashok and Walunj, Manisha B. and Torris, Arun and Badiger, Manohar V. and Srivatsan, Seergazhi G.} } @article {46288, title = {Studies on the use of sodium polyacrylate (SPA) for low-salt animal skin preservation}, journal = {Environmental Science and Pollution Research}, volume = {26}, year = {2019}, month = {SEP}, pages = { 27100-27111}, type = {Article}, abstract = {

Salt-based preservation is practiced for decades in the leather industry because of its versatility, cost-effectiveness, and availability. The salt removed from the soaking process causes significant pollution including organic and elevated total dissolved solids (TDS). Hence, a low-salt skin preservation method using commercial sodium polyacrylate with a reduced quantity of sodium chloride aiming to retain leather properties and pollution reduction was the principal focus of the study. Commercial sodium polyacrylate initially characterized for water absorption capacity along with structural and functional properties is confirmed by NMR and IR spectroscopic techniques. In preliminary experiments, the process parameters attained optimized conditions of sodium polyacrylate (SPA) quantity (5\%), a minimal amount of salt (15\%), and contact time (4 h) required for skin preservation. Besides, reusability studies after SPA recovery (95\%) were applied to skins with an optimized quantity of SPA and salt subsequently stored for 15 days along with control (40\% salt). The results revealed that SPA with low salt aided an adequate curing efficiency with a substantial reduction (\> 65\%) of TDS and comparable physical and organoleptic properties on par with the conventional method. Overall, SPA supported low-salt skin preservation reduces pollutant load (TDS) caused due to using of 40\% sodium chloride in the conventional curing process.

}, doi = {10.1007/s11356-019-05871-y}, author = {Balasubramanian, Venkatakrishnan and Velappan, Brindha and Vijayan, Sandhya Kurvilla and Jabamani, Hepzibah and Nagarajan, Vedaraman and Victor, John Sundar and Ranganath, Suresha P. and Badiger, Manohar V. and Chinnaraj, Velappan kandukalpatti and Chellappa, Muralidharan} } @article {47166, title = {Vivo wound healing performance of halloysite clay and gentamicin-incorporated cellulose ether-PVA electrospun nanofiber mats}, journal = {ACS Applied Bio Materials}, volume = {2}, year = {2019}, month = {SEP}, pages = {4324{\textendash}4334}, type = {Article}, abstract = {

Wound healing is a dynamic and complex process that requires a suitable environment to enhance the rapid healing process. In this context, fabrications of nanofibrous materials with antibiotic and antibacterial properties are becoming extremely important. In this present work, we report on the fabrication and characterization of electro-spun cellulose ether-PVA nanofiber mats loaded with halloysite clay (HNT) and gentamicin sulfate (GS) for faster wound healing applications. The morphology of nanofiber mats was examined by SEM and TEM. The average diameter of the nanofiber mats were in the range of 325 {\textpm} 30 nm. The physicochemical characterizations were done by FT-IR and XRD, which reveal the presence of HNT and GS into the nanofibers. The incorporation of halloysite gave good mechanical strength to the nanofiber mats. Swelling studies indicated the hydrophilicity of the mats. In vitro studies revealed that HNTs are nontoxic to L929 fibroblast cells and also promote cell growth and proliferation. The antibacterial property of HNT was also studied. The slow release of GS from the nanofiber mats was observed for a period of 18 days. The in vivo wound healing studies on the wistar rats for 21 days revealed the wound healing faster within 2 weeks by the incorporation of HNT and GS into the nanofiber mats and hence these nanofiber mats show great potential in acute and chronic wound healing applications.

}, doi = {10.1021/acsabm.9b00589}, author = {Wali, Ashwini and Gorain, Mahadeo and Inamdar, Satish and Kundu, Gopal and Badiger, Manohar V.} } @article {46947, title = {Biofilm formation to inhibition: role of zinc oxide-based nanoparticles}, journal = {Materials Science \& Engineering C-Materials for Biological Applications}, volume = {108}, year = {2020}, month = {MAR}, pages = {110319}, type = {Review}, abstract = {

Zinc oxide nanoparticles have received much attention worldwide as they possess unique properties like varied morphology, large surface area to volume ratio, potent antibacterial activity, and biocompatibility. Biofilm contains homogenous or heterogeneous microorganisms that remain enclosed in a matrix of an extracellular polymeric substance on biotic or abiotic surfaces. Bacterial biofilm formed on medical devices such as central venous catheters, urinary catheters, prosthetic joints, cardiovascular implantable devices, dental implants, contact lenses, intrauterine contraceptive devices and breast implants cause persistent infections. Such biofilm-associated infections in medical implants cause serious problems for public health and affect the function of medical implants. So, there is an urgent need for the use of an antimicrobial agent that will inhibit biofilm, including such antibiotic-resistant bacterial strains as bacteria, to develop multiple drug-resistances resulting in failure of the antibiotic{\textquoteright}s action. The antimicrobial agent used should be ideal in terms of biocompatibility, antimicrobial activity, stability at different environmental conditions, with less sensitivity to the development of resistance towards micro-organisms, safe for in vivo and in vitro use, and remain non-hazardous to the environment, etc. The first objective of the review discusses the insights into the formation of biofilm on a medical device with the current strategies to inhibit. The second purpose is to review the recent progress in ZnO- based nanostructure including composites for antibacterial and anti-biofilm activities. This will offer a new opportunity for the application of Zinc oxide-based material in the prevention of biofilm on the medical devices.

}, keywords = {antibacterial activity, Antibiofilm agent, Biocompatibility, Biofilm, Nanocomposites, ZnO nanoparticles}, issn = {0928-4931}, doi = {10.1016/j.msec.2019.110319}, author = {Mahamuni-Badiger, Pranjali P. and Patil, Pooja M. and Badiger, Manohar V. and Patel, Pratikshkumar R. and Thorat-Gadgil, Bhagyashi S. and Pandit, Abhay and Bohara, Raghvendra A.} } @article {47603, title = {Sulfonated polyvinyl alcohol ionomer membrane favoring smooth electrodeposition of zinc for aqueous rechargeable zinc metal batteries}, journal = {Sustainable Energy \& Fuels}, volume = {5}, year = {2021}, month = {OCT}, pages = {5557-5564}, type = {Article}, abstract = {One of the failure mechanisms of aqueous rechargeable zinc metal batteries (AZMBs) involves high surface area zinc (HSAZ)/dendrite-like deposits over the Zn-metal anode during long-term cycling. Negatively charged (anionic) polymeric ionomer electrolyte membranes and separators are known for suppressing the dendrite-/HSAZ-induced failure of AZMBs. However, the preparation of cost-effective and non-fluorinated ionomers from cheap and environmentally friendly polymers is essential to leverage the feasibility of AZMBs. The current work demonstrates the potential of an ionomer electrolyte membrane (P-AS-C-Zn) made by the crystallization-induced physical cross-linking of sulfonated poly (vinyl alcohol) (PVS) and poly (vinyl alcohol) (PVA) as a dendrite-/HSAZ-inhibiting separator for AZMBs. The P-AS-C-Zn membranes exhibited excellent Zn plating/stripping behavior with a stable voltage vs. time profile beyond 1100 h, compared to their neutral PVA-C-Zn counterpart without any ionomer character (cell failure at close to 280 h). Applying the optimized P-AS-C-Zn membrane in a MnO2||Zn full cell helps retain about 50\% of the initial capacity close to 600 cycles in the absence of extra manganese salt in the electrolyte, which is indeed promising.}, issn = {2398-4902}, doi = {10.1039/d1se00865j}, author = {Vijayakumar, Vidyanand and Torris, Arun and Kurian, Maria and Mathew, Megha Mary and Ghosh, Meena and Khairnar, Ajay B. and Badiger, Manohar V. and Kurungot, Sreekumar} } @article {49308, title = {F-doped nickel cobalt oxide-carbon composite electrocatalysts paired with mechanically robust anion-conducting chitosan membranes for flexible and rechargeable zinc-air batteries}, journal = {ACS Applied Energy Materials}, volume = {7}, year = {2024}, month = {AUG}, pages = {7037-7054}, type = {Article}, abstract = {

High-performing, cost-effective electrocatalysts and anion-conducting polymer electrolyte membranes are essential for realizing commercially affordable zinc-air batteries (ZABs). In this context, the present work deals with the development of a bifunctional electrocatalyst and an anion-exchange quasi-solid-state electrolyte membrane (based on quaternary ammonium group-grafted chitosan) for demonstrating flexible and rechargeable ZABs. The electrocatalyst composed of NiCoO2 nanoparticles supported on a carbon framework showcased substantial advancements in its ability to catalyze both oxygen reduction and evolution reactions (ORR and OER) due to the heteroatom doping by fluorine. For instance, the optimized electrocatalyst (F-NCO-ADC-600) exhibited an onset potential of 0.96 V vs RHE with a half-wave potential of 0.83 V vs RHE for ORR, a comparable performance with the state-of-the-art Pt/C (1.0 and 0.86 V vs RHE, respectively). On a similar note, the same catalyst also displayed an overpotential of 340 mV vs RHE for OER at a current density of 20 mA cm(-2), close to that of a standard RuO2 catalyst (337 mV vs RHE). In the context of polymer electrolytes, the quaternary ammonium-group-grafted chitosan membrane depicted superior ionic conductivity, liquid electrolyte uptake, and mechanical properties, thereby proving to be an efficient anion-conducting polymer electrolyte membrane. The realistic application of the developed electrocatalyst and the polymer electrolyte membrane is demonstrated in the ZAB prototypes. The assembled rechargeable ZAB (RZAB) delivered a power density of 207 mW cm(-2) and maintained high-rate capability and cycling stability, notably in a flexible configuration (f-RZABs). Thus, this work provides a strategy for the rational design of anion-exchange membranes and bifunctional electrocatalysts for f-RZABs.

}, keywords = {anion-conducting polymer electrolytemembrane, F-doping, flexible and rechargeable zinc-air batteries(f-RZABs), oxygen evolution reaction(OER), oxygen reduction reaction (ORR)}, issn = {2574-0962}, doi = {10.1021/acsaem.4c01261}, author = {Kurian, Maria and Ranganath, Suresha P. and Vijayakumar, Vidyanand and Sivadasan, Sneha and Kurian, Rachna Maria and Badiger, Manohar V. and Kurungot, Sreekumar} } @article {49839, title = {Influence of hydrophilic/hydrophobic diols on the properties of polyurethane hydrogels: solvent-free one-pot synthesis}, journal = {Journal of Materials Chemistry B}, volume = {13}, year = {2025}, month = {SEP}, pages = {11010-11019}, type = {Article}, abstract = {

Herein, we report the design and synthesis of bio-degradable porous polyurethane hydrogels by a green, solvent-free, one-pot technique that can withstand physiological mechanical loads and aid in tissue regeneration. The hydrophilic/hydrophobic nature of the hydrogel was tuned using diols such as polycaprolactone diol (PCL) and polycarbonate diol (PCD), in combination with polyethylene glycol (PEG, MW approximate to 4000 g mol-1), 4,4 {\textquoteleft}-methylene bis(cyclohexyl isocyanate) (H12MDI) and hexanetriol (HT), which served as crosslinking agents. The structural characterizations of the hydrogels were performed using FT-IR as well as 1H and 13C high resolution magic angle spinning nuclear magnetic resonance (HR-MAS) spectroscopy. The utilization of various diols in the synthesis of the hydrogels enabled precise control over crystallinity, pore sizes, and customization of mechanical and degradation properties. These hydrogels exhibited tensile strength in the range of 0.22-1.48 MPa, while their compressive strength varied from 0.92 to 29.3 MPa. In vitro degradation profiles in the presence and absence of the enzyme Amano lipase PS revealed that the degradation process is contingent upon the specific diol present in the hydrogel. Furthermore, preliminary in vitro biological experiments confirmed the biocompatibility of the gels, indicating their potential as suitable substrates for drug delivery applications. This diverse library of gels can be shaped into specific forms, highlighting their promising applications as scaffolds and implants in drug delivery systems and tissue engineering.

}, issn = {2050-750X}, doi = {10.1039/d5tb00928f}, author = {Divakaran, Anumon V. and Nair, Sanoop B. and Karambe, Shivani S. and Wadgaonkar, Prakash P. and Nair, Kiran Sukumaran and Badiger, Manohar V.} } @article {50016, title = {High-performance sultone-modified PVA/PAMPS semi-IPN hydrogels for proton exchange membranes}, journal = {Journal of Applied Polymer Science}, volume = {143}, year = {2026}, month = {APR}, type = {Article}, abstract = {

Hydrogel membranes composed of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and sultone-modified poly(vinyl alcohol) (PVA) were successfully synthesized and evaluated as promising proton-conducting materials. A key advantage involves the premodification of PVA with 1,3-propane sultone to introduce sulfonic acid groups, thereby imparting proton conductivity to the PVA backbone. This sultone-modified PVA was then physically entangled within a PAMPS cross-linked network to form novel semi-interpenetrating network (semi-IPN) hydrogels. This synergistic design leverages the excellent film-forming and mechanical properties of PVA with the high proton conductivity inherent to PAMPS. The synthesized membranes exhibited robust mechanical properties, with tensile strengths ranging from 5 to 30 MPa and percentage elongations between 200\% and 400\%, depending on their humidity content. These hydrogel membranes demonstrated proton conductivities ranging from 0.6 to 4.3 x 10-2 S cm-1. The activation energy for proton conduction was found to be as low as 3.5 kJ mol-1, significantly lower than that of the commercial benchmark membrane, Nafion 117 (12 kJ mol-1). These findings underscore the potential of these novel PAMPS/sultone-modified PVA semi-IPN hydrogel membranes for advanced fuel cell applications.

}, keywords = {batteries and fuel cells, functionalization of polymers, Gels, membranes, polyelectrolytes}, issn = {0021-8995}, doi = {10.1002/app.70462}, author = {Patwadkar, Manjusha V. and Illathvalappil, Rajith and Torris, Arun and Francis, Sifa C. and Kurungot, Sreekumar and Badiger, Manohar V.} } @article {49864, title = {Insight Into the Influence of Salinity on Flow and Flocculation Behavior of Acrylamide-Based Cationic Polyelectrolyte}, journal = {Journal of Applied Polymer Science}, volume = {143}, year = {2026}, month = {MAR}, type = {Article}, abstract = {

The viscometric behavior of aqueous solutions of acrylamide and acrylamidopropyl trimethylammonium chloride copolymers (AM-co-APTMAC) with varying cationic content under different salinity conditions was studied. Viscometric measurements were employed to determine intrinsic viscosity and quantify the influence of electrostatic interactions on chain conformation. Rheology experiments were performed to probe dynamic flow behavior under shear to obtain insights into polyelectrolyte viscoelastic properties under conditions mimicking industrial processes. Viscometric and rheology data analysis is augmented with insights from NMR relaxation and pulsed field gradient NMR diffusion experiments. Further, flocculation of kaolin suspensions was studied using aqueous solutions of AM-co-APTMAC copolymers with different charge fractions in the presence and absence of salt. The physicochemical insights on the behavior of AM-co-APTMAC polyelectrolytes in solution from this study could be relevant in practical applications, such as plants that use seawater or in cases where the ionic strength of suspensions is high due to salinity in the medium.

}, keywords = {copolymers, polyelectrolytes, structure property relationships, theory and modeling}, issn = {0021-8995}, doi = {10.1002/app.70219}, author = {Ranganath, Suresha P. and Kurian, Rachna and Torris, Arun and Khairnar, Ajay and Ravindranathan, Sapna and Rajamohanan, P. R. and Badiger, Manohar V. and Wolf, Bernhard A.} }