02906nas a2200229 4500008004100000245010500041210006900146260000800215300001200223490000800235520210600243100002802349700001702377700002702394700002102421700002202442700002102464700002402485700002302509700001902532856012502551 2017 eng d00aThermo-responsive PNIPAM-metal hybrids: an efficient nanocatalyst for the reduction of 4-nitrophenol0 aThermoresponsive PNIPAMmetal hybrids an efficient nanocatalyst f cOCT a753-7630 v4203 aMicron size thermoresponsive cross-linked polymeric microgels of poly(N-isopropylacrylamide) (PNIPAM) are used as "microreactor" for embedding metal nanoparticles of different shapes. Using a simple and robust method, we have synthesized various polymer-metal hybrid nanostructures incorporated with Au nanorods (AuNR), Au nanospheres (AuNS) and Ag nanospheres (AgNS). These hybrid nanostructures have been characterized by transmission electron microscope (TEM), UV-vis spectroscopy, dynamic light scattering (DLS) and static light scattering (SLS) followed by their catalytic activity. TEM studies directly confirmed the mondispersity of synthesized hybrid microgels and stability of the embedded metal nanoparticles within the microgels. Optical studies confirmed the presence of respective absorption bands that correspond to AuNS, AgNS and AuNR respectively. Extensive DLS studies demonstrated that although these hybrid microgels preserve their thermoresponsive properties, i.e their hydrodynamic radius decreased with increasing temperature, their thermosensitivity were comparatively lesser than pure PNIPAM microgels. Combining with studies using static light scattering, we further found that AuNS and AgNS were inhomogeneously distributed within microgels where the majority of the nanoparticles present within the loosely cross-linked shell. On the other hand AuNR were distributed more homogeneously within the microgels. Catalytic performance of various nanostructures loaded onto PNIPAM microgel beads were evaluated by studying the catalytic reduction of 4-nitrophenol. Complete catalytic conversion using AgNS occurred in similar to 30 min with a first-order rate constant of 0.159 min(-1) having a 7 min induction period. On the other hand no induction period was observed for AuNS and AuNR and the reaction completed in 3-4 min with a first-order rate constant of 1.607 min(-1) and 1.627 min(-1) respectively. Further, PNIPAM-AuNS and PNIPAM-AuNR possess better catalytic activity as well as recyclability compared to that of PNIPAM-AgNS. (C) 2017 Elsevier B.V. All rights reserved.1 aSatapathy, Smith, Sagar1 aBhol, Prachi1 aChakkarambath, Aswathy1 aMohanta, Jagdeep1 aSamantaray, Kunal1 aBhat, Suresh, K.1 aPanda, Subhendu, K.1 aMohanty, Priti, S.1 aSi, Satyabrata uhttps://library.ncl.res.in/content/thermo-responsive-pnipam-metal-hybrids-efficient-nanocatalyst-reduction-4-nitrophenol02058nas a2200217 4500008004100000022001400041245010900055210006900164260000800233300001000241490000800251520131600259653001301575653002501588653001401613653001801627100002201645700002101667700002301688856012901711 2019 eng d a0021-979700aAlternating electric-field-induced assembly of binary mixtures of soft repulsive ionic microgel colloids0 aAlternating electricfieldinduced assembly of binary mixtures of  cMAY a88-950 v5443 a

An external alternating electric field is used to study the assembly of a binary mixture of Poly(N-isopro pylacrylamide-co-acrylic acid) microgels in their swollen form at hydrodynamic size ratio 2:1 under deprotonated state. The AC field experiments were carried out at a fixed frequency of 100 kHz in the fluid regime for three number density ratios 1:3, 1:1 and 3:1 of big-to-small microgels using a confocal microscope. Strings with different types of co-assembly structures such as buckled, ring, flame and sandwich have been observed at low and intermediate field strengths at ratio 1:3, 1:1. In buckled and ring type, one or two small particles sit at the contact of two big particles and in the flame type, small particles arrange like a cone at end of the string. In the sandwich structure, several double small particle layers lie in between big particles. At high field strength, aggregation of strings and a phase separation into individual aggregates of strings from both big and small microgels have been observed. At higher ratio 3:1, the string formation is mostly dominated by big particles. Our experimental results are discussed with the recent simulation and experimental works on AC field induced structures in binary hard sphere mixtures. (C) 2019 Elsevier Inc. All rights reserved.

10aassembly10adipolar interactions10aMicrogels10aSoft colloids1 aJathavedan, Kiran1 aBhat, Suresh, K.1 aMohanty, Priti, S. uhttps://library.ncl.res.in/content/alternating-electric-field-induced-assembly-binary-mixtures-soft-repulsive-ionic-microgel03001nas a2200301 4500008004100000022001400041245008700055210006900142260000900211300001100220490000800231520202600239653002902265653002202294653002102316653003402337653003402371100001902405700002802424700002602452700001702478700001602495700002102511700001702532700002102549700002302570856010602593 2023 eng d a0167-732200aPolymerized stimuli-responsive microgels for the removal of organic dye from water0 aPolymerized stimuliresponsive microgels for the removal of organ cAPR  a1212670 v3753 a

Polymerized hydrogel materials (PGM) containing uniform-sized stimuli-responsive microgel particles could be promising alternatives for solution-based microgels to remove organic dyes from water. In the current work, PGM is prepared using Poly(N-isopropylacrylamide-co-acrylic acid) based anionic microgels and their ability for uptake and release studies with an oppositely charged dye, methylene blue (MB) is carried out using UV-vis spectroscopy. The mechanism of dye adsorption is understood at a single particle level using light scattering, and zeta potential and the contributions from different molecular interactions among dye molecules and constituting entities of microgels are obtained from molecular docking studies. The maximum dye uptake by PGM is around 80 % in the swollen state (at pH 7 and 20 degrees C). In contrast, the dye release studies in the deswollen state (at pH 3 and 50 degrees C) show a decrease in the release efficiency from 87 % to 63 % of the total dye adsorbed in 4-repeated cycles. The adsorption isotherm follows a sigmoidal (S) model that has been majorly used in different multi-layer adsorption systems. Extensive dynamic and static light scattering studies demonstrate a deswelling of hydrody-namic radius and core-shell radius of microgels at low temperatures (20 degrees C) induced by dye adsorption. At higher temperatures, the dye-adsorbed microgels have a higher hydrodynamic radius than the pure microgels due to the remaining dye molecules within the microgel that do not release even in the deswollen state. Molecular docking studies show that electrostatic interaction dominates between COO- and MB and van der Waals/hydrophobic dominates for MB-NIPAM and MB-COOH docking complex respectively. Our work covering adsorption/desorption properties of the material to the single-particle level can provide a better understanding in formulating reusable smart materials for the remediation of different water pollutants.(c) 2023 Elsevier B.V. All rights reserved.

10adynamic light scattering10aMolecular docking10aPNIPAM microgels10aRemoval of organic pollutants10aStimuli -responsive microgels1 aPany, Biswajit1 aMajundar, Amrito, Ghosh1 aMohanty, Madhuchhanda1 aFyis, K., P.1 aDey, Tanima1 aTripathy, Gautam1 aBhat, Suresh1 aYamanaka, Junpei1 aMohanty, Priti, S. uhttps://library.ncl.res.in/content/polymerized-stimuli-responsive-microgels-removal-organic-dye-water02558nas a2200265 4500008004100000245013000041210006900171260000800240300001100248490000700259520160800266653002101874653002701895653002701922653002101949653003601970653003302006100001902039700002802058700001702086700001802103700002102121700002302142856012702165 2024 eng d00aPolymerized stimuli-responsive microgel hybrids of silver nanoparticles as efficient reusable catalyst for reduction reaction0 aPolymerized stimuliresponsive microgel hybrids of silver nanopar cMAR ae262440 v103 a

We have showcased the potential of polymerized hydrogels (PGMs) with uniform -sized stimuliresponsive microgel particles as promising alternatives to prevent aggregation in solution based nanoparticle systems. In the current work, we implemented the PGM concept by embedding anionic stimuli -responsive microgels (PNIPAM-co-AAc)-silver (Ag) hybrids within a hydrogel matrix. These PGM@AgNP hybrid materials are used as catalysts for the reduction of 4-nitrophenol (4 -NP) to 4-aminophenol (4 -AP) in the presence of sodium borohydride. UV-VIS spectroscopy is used for studying catalytic activity. In the solution based system, the complete reduction of 4NP to 4 -AP took 30 minutes with pure Ag nanoparticles, 24 minutes with PNIPAM-Ag hybrid (Neutral) microgels and 15 minutes with PNIPAM-co-AAc-Ag (Anionic) hybrid microgels. In contrast PGM containing PNIPAM-co-AAc-Ag hybrids achieved full reduction in just 15 minutes, along with a 3 -minute induction period. For pure Ag nanoparticles, the first -order rate constant is found to be 0.25 min - 1, for PNIPAM-Ag hybrid (Neutral), it is 0.21 min- 1 and for PNIPAM-coAAc-Ag (Anionic), it is 0.5 min- 1 where as for PGM containing anionic microgel hybrids it is found to be 0.8 min - 1. Furthermore, the reusability of the PGM-Ag (anionic) materials for catalytic activity remains unaltered even after several washings. In summary, our study highlights the effectiveness of PGM@AgNP materials as efficient catalysts for the reduction of 4-nitrophenol to 4-aminophenol, indicating their versatile potential in various catalytic applications.

10aLight scattering10aMicrogel-metal hybrids10aNanomaterial catalysts10aPNIPAM microgels10aPolymerized hydrogel matrix(PGM10aStimuli-responsive microgels1 aPany, Biswajit1 aMajumdar, Amrito, Ghosh1 aBhat, Suresh1 aSi, Satybrata1 aYamanaka, Junpei1 aMohanty, Priti, S. uhttps://library.ncl.res.in/content/polymerized-stimuli-responsive-microgel-hybrids-silver-nanoparticles-efficient-reusable