02237nas a2200181 4500008004100000245009800041210006900139260000800208300001400216490000700230520157300237100002601810700001501836700002201851700003101873700002401904856012701928 2018 eng d00aCross-metathesis of biorenewable dioxalates and diols to film-forming degradable polyoxalates0 aCrossmetathesis of biorenewable dioxalates and diols to filmform cJUL a1584-15920 v563 aStarting from commonly available sugar derivatives, a single step protocol to access a small family of isohexide-dioxalates (2a-c) has been established. The synthetic competence of 2a-c has been demonstrated by subjecting them to condensation polymerization. Quite surprisingly, the proton NMR of poly(isomannide-co-hexane)oxalate revealed a 1:2 ratio between isomannide-dioxalate (2a) and 1,6-hexanediol (3a) in the polymer backbone. This intriguing reactivity was found to be an outcome of a cross metathesis reaction between 2a and 3a. The cross metathesis products 3a[2-(2-methoxyacetoxy)ethyl 2-(2-hydroxyethoxy)-2-(3-oxydanylidene)acetate] and 2a(3R,6R)-6-hydroxyhexahydrofuro[3,2-b]-furan-3-yl methyl oxalate were isolated in a control experiment. Based on direct and indirect evidence, and control experiments, an alternative polymerization mechanism is proposed. Polymerization conditions were optimized to obtain polyoxalates P1(2a-3a)-P9(2c-3c) with molecular weights in the range of 14,000-68,000 g/mol, and narrow polydispersities. The identity of the polyoxalates was unambiguously established using 1-2D NMR spectroscopy, MALDI-ToF-MS, and GPC measurements. The practical implication of these polymers is demonstrated by preparing transparent, mechanically robust films. The environmental footprint of the selected polyoxalates was investigated by subjecting them to solution and solid-state degradation. The polyoxalates were found to be amenable to degradation. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1584-15921 aRajput, Bhausaheb, S.1 aRam, Farsa1 aMenon, Shamal, K.1 aShanmuganathan, Kadhiravan1 aChikkali, Samir, H. uhttps://library.ncl.res.in/content/cross-metathesis-biorenewable-dioxalates-and-diols-film-forming-degradable-polyoxalates01980nas a2200277 4500008004100000022001400041245010100055210006900156260000800225300001400233490000700247520102500254653002901279653002201308653002101330653002101351653002301372100002701395700002901422700001501451700002301466700003101489700002301520700003001543856012901573 2018 eng d a1433-785100aFlexible composite mechanical energy harvester from a ferroelectric organoamino phosphonium salt0 aFlexible composite mechanical energy harvester from a ferroelect cJUL a9054-90580 v573 a

A new binary organic salt diphenyl diisopropylamino phosphonium hexaflurophosphate (DPDPPF6) was shown to exhibit a good ferroelectric response and employed for mechanical energy harvesting application. The phosphonium salt crystallizes in the monoclinic noncentrosymmetric space group Cc and exhibits an H-bonded 1D chain structure due to N-HF interactions. Ferroelectric measurements on the single crystals of DPDPPF6 gave a well-saturated rectangular hysteresis loop with a remnant (P-r) polarization value of 6Ccm(-2). Further, composite devices based on polydimethylsiloxane (PDMS) films for various weight percentages (3, 5, 7, 10 and 20wt%) of DPDPPF6 were prepared and examined for power generation by using an impact test setup. A maximum output peak-to-peak voltage (V-PP) of 8.5V and an output peak-to-peak current (I-PP) of 0.5A was obtained for the non-poled composite film with 10wt% of DPDPPF6. These results show the efficacy of organic ferroelectric substances as potential micropower generators.

10abinary phosphonium salts10aenergy conversion10aferroelectricity10ahydrogen bonding10apolymer composites1 aVijayakanth, Thangavel1 aSrivastava, Anant, Kumar1 aRam, Farsa1 aKulkarni, Priyangi1 aShanmuganathan, Kadhiravan1 aPraveenkumar, Balu1 aBoomishankar, Ramamoorthy uhttps://library.ncl.res.in/content/flexible-composite-mechanical-energy-harvester-ferroelectric-organoamino-phosphonium-salt02185nas a2200253 4500008004100000022001400041245011300055210006900168260000800237300001600245490000800261520131000269100001501579700001901594700001901613700002801632700001901660700001801679700002501697700002501722700002701747700003101774856012601805 2018 eng d a1932-744700aFluorinated nanocellulose-reinforced all-organic flexible ferroelectric nanocomposites for energy generation0 aFluorinated nanocellulosereinforced allorganic flexible ferroele cJUL a16540-165490 v1223 a

We report here enhanced ferroelectric crystal formation and energy generation properties of polyvinylidene fluoride (PVDF) in the presence of surface-modified crystalline nanocellulose. Incorporation of only 2-5 wt % fluorinated nanocellulose (FNC) in PVDF has been found to significantly induce polar beta/gamma-phase crystallization as compared to the addition of unmodified nanocellulose (carboxylated nanocellulose). A device made up of electrically poled PVDF/FNC composite films yielded 2 orders of magnitude higher voltage output than neat PVDF in vibrational energy harvesting. This remarkable increase in energy generation properties of PVDF at such a low loading of an organic natural biopolymer could be attributed to the tailored surface chemistry of nanocellulose, facilitating strong interfacial interactions between PVDF and FNC. Interestingly, energy harvesting devices fabricated from PVDF/FNC nanocomposites charged a 4.7 mu F capacitor at significantly faster rate and the accumulated voltage on capacitor was 3.8 times greater than neat PVDF. The fact that PVDF/FNC nanocomposites still retain a strain at break of 10-15% and can charge a capacitor in few seconds suggests potential use of these nanocomposites as flexible energy harvesting materials at large strain conditions.

1 aRam, Farsa1 aAmbone, Tushar1 aSharma, Aakash1 aMurugesan, Rajarathinam1 aKajale, Deepak1 aBorkar, Vivek1 aAli, Shaikh, Faruque1 aBalu, Praveen, Kumar1 aKumaraswamy, Guruswamy1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/fluorinated-nanocellulose-reinforced-all-organic-flexible-ferroelectric-nanocomposites01889nas a2200229 4500008004100000245010700041210006900148260000800217300001000225490000800235520107000243100002801313700002201341700002101363700001501384700002901399700002601428700002201454700002601476700003101502856012601533 2018 eng d00a Functionalized carbon nanotube reinforced polymer nanocomposite microcapsules with enhanced stiffness0 aFunctionalized carbon nanotube reinforced polymer nanocomposite  cAUG a82-890 v5503 aMicrocapsules with tunable mechanical properties are highly desirable in pressure sensitive applications. We report here a facile approach to prepare polyurea/multiwall carbon nanotube (MWCNTs) nanocomposite microcapsules (MICs) with enhanced stiffness. A model compound dimethyl phthalate (DMP) was used as core material. MWCNTs were modified with reactive functional groups namely carboxyl (-COOH), amines (-NH2), and isocyanates (-NCO) to ensure a stronger interface between polymer wall and MWCNTs. Functionalization of MWCNTs was corroborated by Fourier transformed infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was employed to study the surface morphology of MICs. The presence of MWCNTs in the microcapsule wall was confirmed by transmission electron microscopy (TEM). MICs with functionalized MWCNTs show almost 100% increase in stiffness with respect to pristine capsules. All MICs show 92-97 +/- 1% encapsulation efficiency. The approach used in this paper can be broadly utilized to tune the mechanical properties of the microcapsules.1 aJagtap, Siddheshwar, B.1 aPatil, Vishal, D.1 aSuresh, Karthika1 aRam, Farsa1 aMohan, Muthu, Subramania1 aRajput, Shatruhan, S.1 aPatil, Shivprasad1 aShukla, Parshuram, G.1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/functionalized-carbon-nanotube-reinforced-polymer-nanocomposite-microcapsules-enhanced00654nas a2200133 4500008004100000245007100041210006900112260004700181520012200228100003100350700001500381700002200396856010200418 2018 eng d00aMelanin-based composite materials for multifunctional applications0 aMelaninbased composite materials for multifunctional application aBoston, MAbAmerican-Chemical-SocietycAUG3 a256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond1 aShanmuganathan, Kadhiravan1 aRam, Farsa1 aPimpalkar, Nikhil uhttps://library.ncl.res.in/content/melanin-based-composite-materials-multifunctional-applications02715nas a2200181 4500008004100000245011800041210006900159260000800228300001500236490000700251520202700258100002702285700001502312700002302327700003102350700003002381856012202411 2019 eng d00aAll-organic composites of ferro- and piezoelectric phosphonium salts for mechanical energy harvesting application0 aAllorganic composites of ferro and piezoelectric phosphonium sal cAUG a 5964-59720 v313 a

Molecular ferroelectrics owing to their lightweight, flexibility, and phase stability are drawing attention in the fields of flexible electronics, optical devices, and energy materials. In this paper, we report a series of binary organoamino phosphonium salts containing triphenyl isopropylaminophosphonium (TPAP), diphenyl diisopropylaminophosphonium (DPDP), phenyl triisopropylaminophosphonium (PTAP), and tetraisopropylaminophosphonium (TIAP) cations supported by lower symmetric tetrahedral BF4-, ClO4-, and IO4- anions. The P-E hysteresis loop measurements on these polar organic salts gave high remnant polarization (P-r) values of 35.36, 21.83, and 21.12 mu C cm(-2) for the DPDP center dot BF4, DPDP center dot ClO4, and DPDP center dot IO4 salts, respectively, having 1D hydrogen-bonded chain structures built from strong N-H center dot center dot center dot X (X = F or 0) interactions. For the first time, highly flexible composite devices have been prepared for the piezoelectric salts TPAP center dot BF4, DPDP center dot BF4, and TIAR center dot BF4 using thermoplastic polyurethane (TPU) as the matrix. The observed maximum peak-to-peak output voltages (V-pp) for the 10 wt % composite devices of TPAP center dot BF4/TPU, DPDP center dot BF4/TPU, and TIAP center dot BF4/TPU are found to be 7.37, 8.95, and 4.75 V, respectively. These composite devices exhibit excellent durability, cycling stability, and viscoelastic properties. They also show the capacitor charging capabilities reaching their maximum charging points within 60 s.

1 aVijayakanth, Thangavel1 aRam, Farsa1 aPraveenkumar, Balu1 aShanmuganathan, Kadhiravan1 aBoomishankar, Ramamoorthy uhttps://library.ncl.res.in/content/all-organic-composites-ferro-and-piezoelectric-phosphonium-salts-mechanical-energy02071nas a2200169 4500008004100000245009500041210006900136260000800205300001600213490000600229520144700235100001501682700002701697700001901724700003101743856012701774 2019 eng d00aHighly flexible mechanical energy harvester based on nylon 11 ferroelectric nanocomposites0 aHighly flexible mechanical energy harvester based on nylon 11 fe cJUL a1998–20050 v13 a

We report here a flexible piezoelectric energy harvester using castor-oil-derived nylon 11 and biomass-derived cellulose nanocrystals (CNC). Using a simple solution casting process, we were able to fabricate flexible large area nylon 11 and composite films. Neat nylon 11 films crystallized predominantly in the α- phase. Incorporation of CNC at a low concentration of 2–5 wt % resulted in almost complete transition of α-phase to polar γ-phase, which could be attributed to strong hydrogen bonding interactions between CNC and amide groups in nylon 11. This remarkable shift in crystallization behavior also led to enhanced piezoelectric performance. We also found that the addition of 5 wt % glycerol (on the dry weight of nylon 11 or composite) enhanced the flexibility of the film. Energy harvesting devices made from 5 wt % nylon 11/CNC films showed about 2.6 times higher output voltage as compared to neat nylon 11 devices under similar impact conditions, and the effect was durable over 800 cycles. These devices were also used to charge a 10 μF polarized capacitor, and we found that the 5 wt % nylon 11/CNC devices charged up to 3.78 V in 90 s, which is 2.8 times higher than nylon 11 devices. To the best of our knowledge, this is the first report on nylon 11 nanocomposites, where cellulose nanocrystals have been used to enhance the electroactive γ phase in nylon 11 and yield such high piezoelectric performance.

1 aRam, Farsa1 aRadhakrishnan, Sithara1 aAmbone, Tushar1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/highly-flexible-mechanical-energy-harvester-based-nylon-11-ferroelectric-nanocomposites02021nas a2200241 4500008004100000022001400041245008900055210006900144260000800213300001200221490000700233520126300240653001401503653001501517653001801532653001301550100001701563700001701580700001501597700003101612700002101643856011501664 2019 eng d a1751-616100aInfluence of nanocellulose on mechanics and morphology of polyvinyl alcohol xerogels0 aInfluence of nanocellulose on mechanics and morphology of polyvi cFEB a275-2830 v903 a

Xerogels are porous networks of crosslinked polymers that are useful for biomedical applications such as drug delivery, scaffold engineering, tissue regeneration, cell culture and wound dressing. However, inferior mechanical properties curtail their applications to a considerable extent. Nanocellulose fibers and crystals are often added into the polymer matrix to improve their mechanical strength. Here, nanocellulose in the mass ratios of 7%, 13% and 18% are loaded into polyvinyl alcohol (PVA) matrix followed by thermo-morpho-mechanical characterization. With increase in nanocellulose content, thermal degradation occurs at a lower temperature. It is observed that addition of higher quantity of nanocellulose crystals leads to the formation of weak cellulose rich regions causing xerogel rupture. This is predominantly observed for xerogel loaded with 18% nanocellulose crystals. Similarly, addition of higher quantity of nanocellulose fibers increase brittleness of the xerogels causing fracture. This is predominantly observed for xerogel loaded with 18% nanocellulose fibers. Creep strain and stress relaxation is observed to decrease with addition of nanocellulose loading owing to molecular chain restriction and polymer chain immobility.

10aMechanics10aMorphology10aNanocellulose10aXerogels1 aPramanik, R.1 aGanivada, B.1 aRam, Farsa1 aShanmuganathan, Kadhiravan1 aArockiarajan, A. uhttps://library.ncl.res.in/content/influence-nanocellulose-mechanics-and-morphology-polyvinyl-alcohol-xerogels00530nas a2200133 4500008004100000022001400041245008900055210006900144260000800213490000800221100003100229700001500260856012100275 2019 eng d a0065-772700aNanocellulose reinforced polymer composites as flexible mechanical energy harvesters0 aNanocellulose reinforced polymer composites as flexible mechanic cAUG0 v2581 aShanmuganathan, Kadhiravan1 aRam, Farsa uhttps://library.ncl.res.in/content/nanocellulose-reinforced-polymer-composites-flexible-mechanical-energy-harvesters02673nas a2200265 4500008004100000022001400041245012700055210006900182260000800251300001400259490000600273520174800279653002502027653002302052653002602075653001402101653001702115653003302132100001502165700002602180700002402206700002102230700003102251856012502282 2020 eng d a2574-096200aEnhancing thermomechanical and chemical stability of polymer electrolyte membranes using polydopamine coated nanocellulose0 aEnhancing thermomechanical and chemical stability of polymer ele cFEB a1988-19990 v33 a

We report here an approach to enhance the chemical and thermomechanical stability of polymer electrolyte membranes without compromising proton conductivity. Multifunctional polydopamine coated nanocellulose (PNC) was prepared by oxidative polymerization of dopamine on nano cellulose fibers and subsequently incorporated in Nafion by solution blending. PNC had a very significant effect on the thermomechanical properties of Nafion showing up to 200% improvement in the storage modulus at 90 degrees C. The PNC network also enhanced the dimensional stability of Nafion under constant stress. The 3 wt % PNC composite membrane showed a drastic reduction in creep compliance of about 39.9% and 46.5% in J(max) at 30 degrees and 60 degrees C, respectively. Free radical scavenging properties of polydopamine also helped to significantly enhance the chemical stability of Nafion, which was ascertained by accelerated degradation tests conducted in Fenton's reagent at 70 degrees C over 40 days. F-19 CP MAS solid state NMR, FTIR, and tensile tests on the membranes show higher chemical stability of the 3 wt % PNC composite membrane. The proton conductivity of the 3 wt % PNC composite membrane at 90 degrees C and 100% RH (similar to 125 mS/cm) was slightly higher than the Nafion membrane (similar to 94 mS/cm) at similar conditions. The retention of proton conductivity even with lower water uptake could be ascribed to proton hopping through polydopamine coated nanocellulose. Performance of the composite membrane was also evaluated in a single stack fuel cell and found to be better than recast Nafion. The benefits derived by this approach are not restricted to Nafion alone and shall broadly apply to many other polymer membranes.

10acellulose nanofibers10achemical stability10adimensional stability10afuel cell10apolydopamine10apolymer electrolyte membrane1 aRam, Farsa1 aVelayutham, Parthiban1 aSahu, Akhila, Kumar1 aLele, Ashish, K.1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/enhancing-thermomechanical-and-chemical-stability-polymer-electrolyte-membranes-using02069nas a2200289 4500008004100000022001400041245013000055210006900185260000800254300001400262490000600276520112500282653001401407653001401421653001801435653001301453653001101466653001401477100001501491700002001506700002701526700002101553700001801574700003001592700003101622856012601653 2020 eng d a2637-610500aNanocellulose reinforced flexible composite nanogenerators with enhanced vibrational energy harvesting and sensing properties0 aNanocellulose reinforced flexible composite nanogenerators with  cJUL a2550-25620 v23 a

We report here enhanced vibration and pressure sensing properties of nanocellulose reinforced flexible composite piezoelectric nanogenerators (PENGs). Surface fluorinated nanocellulose crystals (FNC) were incorporated into poly(vinylidene fluoride) (PVDF) and electrospun into composite nanofibers. Incorporation of only 2 wt % FNC in PVDF resulted in a significant enhancement in pressure sensitivity with a very low detectable pressure limit of 10 Pa and a sensitivity of up to 18 mV/kPa. The composite PENGs also demonstrated very high sensitivity for forced continuous vibrations. 2FNC/PVDF composites resulted in an order of magnitude higher voltage response over neat PVDF for a given strain. When PENGs were mounted on a vacuum pump for transduction of mechanical vibrations into electrical energy, 2FNC/PVDF composite devices manifested similar to 3.8 times enhanced voltage output over neat PVDF and faster charging of a capacitor. The enhanced piezoelectric properties of PVDF/FNC nanocomposites could be attributed to the tailored interface between PVDF and nanocellulose and enhanced polarizability.

10aComposite10aNanofiber10apiezoelectric10apressure10aSensor10avibration1 aRam, Farsa1 aGudadhe, Aniket1 aVijayakanth, Thangavel1 aAherrao, Swapnil1 aBorkar, Vivek1 aBoomishankar, Ramamoorthy1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/nanocellulose-reinforced-flexible-composite-nanogenerators-enhanced-vibrational-energy01998nas a2200169 4500008004100000022001400041245015000055210006900205260000900274300001600283490000600299520133400305100002001639700001501659700002401674856013001698 2020 eng d a2470-134300aPhosphorous-doped graphitic material as a solid acid catalyst for microwave-assisted synthesis of beta-ketoenamines and baeyer-villiger oxidation0 aPhosphorousdoped graphitic material as a solid acid catalyst for cJUL  a15962-159720 v53 a

Synthesis of phosphorous-doped graphitic materials (P-Gc) using phytic acid as a precursor was done in a microwave oven in a cost- and time-effective green way. The material was used as a solid acid catalyst for microwave (MW)-assisted synthesis of beta-ketoenamines and Baeyer-Villiger (By) oxidation. In the case of BV oxidation, hydrogen peroxide (H2O2) was used as a green oxidant. For beta-ketoenamines, in most cases, 100% conversion with an similar to 95% yield was achieved in ethyl acetate medium. In solvent-free conditions, the yield of beta-ketoenamines was similar to 75%. A kinetic study suggested that the resonance stabilization of the positive reaction center happens in the transition state for beta-ketoenamine synthesis. In BV oxidation, cyclic ketones were converted to their corresponding cyclic esters in good to high yields (similar to 80% yield) in a shorter reaction time (6-20 min). As per our knowledge, this is the first report of BV oxidation catalyzed by a heteroatom-doped graphitic material. For BV oxidation, the phosphoric acid functional groups present in P-Gc might increase the electrophilicity of the carbonyl group of the ketones to compensate for the weakness of H2O2 as a nucleophile and a spiro-bisperoxide intermediate has been identified in high-resolution mass spectrometry.

1 aMaity, Sayantan1 aRam, Farsa1 aDhar, Basab, Bijayi uhttps://library.ncl.res.in/content/phosphorous-doped-graphitic-material-solid-acid-catalyst-microwave-assisted-synthesis-beta01920nas a2200253 4500008004100000022001400041245012200055210006900177260000900246300001600255490000700271520100100278653002201279653002601301653003001327653004001357653001501397100002701412700001501439700002301454700003101477700003001508856012801538 2020 eng d a1433-785100aPiezoelectric energy harvesting from a ferroelectric hybrid salt [Ph3MeP](4)[Ni(NCS)(6)] embedded in a polymer matrix0 aPiezoelectric energy harvesting from a ferroelectric hybrid salt cJUN  a10368-103730 v593 a

Organic-inorganic hybrid ferroelectrics are an exciting class of molecular materials with promising applications in the area of energy and electronics. The synthesis, ferroelectric and piezoelectric energy harvesting behavior of a 3d metal ion-containing A(4)BX(6) type organic-inorganic hybrid salt [Ph3MeP](4)[Ni(NCS)(6)] (1) is now presented. P-E hysteresis loop studies on 1 show a remnant ferroelectric polarization value of 18.71 mu C cm(-2), at room temperature. Composite thermoplastic polyurethane (TPU) devices with 5, 10, 15 and 20 wt % compositions of 1 were prepared and employed for piezoelectric energy harvesting studies. A maximum output voltage of 19.29 V and a calculated power density value of 2.51 mW cm(-3) were observed for the 15 wt % 1-TPU device. The capacitor charging experiments on the 15 wt % 1-TPU composite device shows an excellent energy storage performance with the highest stored energies and measured charges of 198.8 mu J and 600 mu C, respectively.

10aenergy conversion10amechanical properties10anon-covalent interactions10aorganic-inorganic hybrid composites10aPhosphorus1 aVijayakanth, Thangavel1 aRam, Farsa1 aPraveenkumar, Balu1 aShanmuganathan, Kadhiravan1 aBoomishankar, Ramamoorthy uhttps://library.ncl.res.in/content/piezoelectric-energy-harvesting-ferroelectric-hybrid-salt-ph3mep4nincs6-embedded-polymer02476nas a2200277 4500008004100000022001400041245012400055210006900179260000800248300001100256490000800267520158800275653001101863653002001874653001401894653001501908653001801923653000901941100001501950700001601965700001701981700002201998700003102020700002102051856012602072 2020 eng d a0925-838800aPVDF/BaTiO3 films with nanocellulose impregnation: investigation of structural, morphological and mechanical properties0 aPVDFBaTiO3 films with nanocellulose impregnation investigation o cMAY a1537010 v8233 a

Polyvinylidene fluoride (PVDF) composite films have witnessed widespread applications in biomedical and flexible electronic devices in recent years. These applications require a material that has enhanced electrical properties, mechanical flexibility along with sufficient strength. A lot of research has been carried out to enhance the piezoelectric and dielectric properties of the PVDF composite films. However, the improvements in the mechanical properties of nano filler reinforced PVDF composite films has not received due attention. In this regard, the present work focuses towards enhancing the mechanical strength and load-bearing capability of PVDF, by preparing composites of PVDF films impregnated with Cellulose Nanocrystals (CNC) and Barium Titanate (BTO) nanoparticles. Solution casting method was adapted to fabricate the PVDF/BTO/CNC films. X-ray diffractograms and FTIR (Fourier Transform infrared spectroscopy) corroborate the presence of ferroelectric gamma phase in PVDF. Mechanical and viscoelastic measurements have been carried out to examine the influence of CNC and BTO nano fillers in the PVDF matrix. The addition of CNC and BTO in PVDF film has improved the mechanical strength significantly. The stress achieved for PVDF/5% BTO and PVDF/5% BTO with 0.9% of CNC at 5% strain was 17% and 130% higher than the pristine PVDF, respectively. This study can be helpful for the design engineers to meet custom/specific requirements for a myriad of end- user applications such as piezoelectric nanogenerators. (C) 2020 Elsevier B.V. All rights reserved.

10aBaTiO310aComposite films10aMechanics10aMorphology10aNanocellulose10aPVDF1 aRam, Farsa1 aKaviraj, P.1 aPramanik, R.1 aKrishnan, Amrutha1 aShanmuganathan, Kadhiravan1 aArockiarajan, A. uhttps://library.ncl.res.in/content/pvdfbatio3-films-nanocellulose-impregnation-investigation-structural-morphological-and02152nas a2200253 4500008004100000022001400041245015200055210006900207260000800276300001400284490000700298520126500305653001201570653001601582653002701598653002201625653002101647100001501668700001801683700001701701700002701718700003101745856012201776 2021 eng d a0969-023900aElastic piezoelectric aerogels from isotropic and directionally ice-templated cellulose nanocrystals: comparison of structure and energy harvesting0 aElastic piezoelectric aerogels from isotropic and directionally  cJUL a6323-63370 v283 a

We report the preparation of highly compressible and elastic piezoelectric aerogels of carboxylated cellulose nanocrystals (CNCs). Aqueous CNC dispersions containing polyethyleneimine and crosslinker were frozen isotropically to yield isotropic aerogels, while oriented aerogels were prepared by directional freezing. These aerogels were highly flexible and porous (similar to 85% void fraction), exhibiting greater than 90% recovery at 50% compressive strain even after 100 compression-decompression cycles. Since such aerogels with low bulk modulus and high anisotropy would be an ideal platform for leveraging the piezoelectric properties of CNCs, we used them to prepare piezoelectric nanogenerator devices and determined their energy transduction behavior. Anisotropic aerogels led to an enhanced open-circuit voltage of 840 mV (at similar to 8 N applied force), which is over 2.6 times higher than isotropic aerogels (320 mV). The energy density of anisotropic aerogels was around 52 nW/cm(2), representing outstanding piezoelectric performance for cellulose-based aerogels. Such aerogels with high compressibility, elastic recovery and exceptional piezoelectric performance could have potential applications in sensors, wearable electronics, etc.

10aAerogel10aAnisotropic10aCellulose nanocrystals10aenergy harvesting10aPiezoelectricity1 aRam, Farsa1 aBiswas, Bipul1 aTorris, Arun1 aKumaraswamy, Guruswamy1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/elastic-piezoelectric-aerogels-isotropic-and-directionally-ice-templated-cellulose02445nas a2200241 4500008004100000022001400041245013500055210006900190260000900259300001600268490000700284520158700291653002901878653002201907653001901929653001801948100001501966700002101981700001702002700002702019700003102046856012602077 2021 eng d a0272-884200aHighly compressible ceramic/polymer aerogel-based piezoelectric nanogenerators with enhanced mechanical energy harvesting property0 aHighly compressible ceramicpolymer aerogelbased piezoelectric na cJUN  a15750-157580 v473 a

Ceramic piezoelectric materials have orders of magnitude higher piezoelectric coefficients compared to polymers. However, their brittleness precludes imposition of large strains in mechanical energy harvesting applications. We report here that ice templating affords low bulk modulus lead-free aerogel piezoelectric nanogenerators (PENG) with unprecedented combination of flexibility and high piezoelectric response (voltage and power density). A modified ice templating protocol was used to fabricate piezoelectric nanocomposites of surface modified BaTiO3 (BTO) nanoparticles in crosslinked polyethylene imine. This protocol allowed incorporating a significantly high fraction of BTO particles (up to 83 wt %) in the aerogel, while retaining remarkably high compressibility and elastic recovery up to 80% strain. The output voltage, at an applied compressive force of 20 N (100 kPa), increased with BTO loading and a maximum output voltage of 11.6 V and power density of 7.22 ?W/cm2 (49.79 ?W/cm3) was obtained for PENG aerogels containing 83 wt% BTO, which is orders of magnitude higher than previously reported values for foam-based piezoelectric energy harvesters. The BTO/PEI PENGs also showed cyclic stability over 900 cycles of deformation. PENGs with higher porosity showed better elastic recovery and piezoelectric properties than lower porosity and higher BTO content aerogels. To the best of our knowledge, this is the first report to demonstrate the piezoelectric properties of high ceramic content aerogels having very high compressibility and elastic recovery.

10aCeramic polymer aerogels10aenergy harvesting10aice templating10apiezoelectric1 aRam, Farsa1 aSuresh, Karthika1 aTorris, Arun1 aKumaraswamy, Guruswamy1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/highly-compressible-ceramicpolymer-aerogel-based-piezoelectric-nanogenerators-enhanced02426nas a2200253 4500008004100000022001400041245014100055210006900196260000800265300001100273490000800284520152300292653003601815653002301851653001701874653002001891653003201911653000901943100001901952700001501971700003101986700002702017856012802044 2022 eng d a0921-510700aCdS cubane type clusters encapsulated by rolling of single layer reduced graphene oxide sheets for enhanced mechanical energy harvesting0 aCdS cubane type clusters encapsulated by rolling of single layer cFEB a1155280 v2763 aComposites with Single Layer Graphene Oxide (SLGO) sheets are extremely difficult to achieve, irrespective of the current advancements in graphene composites research. The difficulties in exfoliating the graphite oxide (GO) was associated with a strong interaction among the edge sides of the adjacent layers. This in-turn barricades the foreign intruders to interact with the basal plane, thereby restraining one to form composites with SLGO sheets. In this work, we had successfully exfoliated GO through a spacer [Cd(OAc)(2) + polyethylene glycol (PEG)] to result in nano-engineered CdS cubane-type clusters in rolled up SLGO to form graphene oxide complex compound (GOCC), resembling carbon nanotubes (CNTs). The CdS cubane-type clusters were found to interacting with the carbon skeleton of rolled reduced SLGO sheet through a Manogate' structures, which was supported by density functional theory (DFT) calculations. Our theoretical study reveals that the obtained complex compound (GOCC) is thermodynamically more favourable than its ancestor materials (CdS cubane and empty CNT). Flexible piezoelectric nanogenerators (PENGs) fabricated from GOCC and thermoplastic polyurethane (TPU) resulted in output voltage (V-oc) of 4.5 V and output current of 0.4 mu A at applied force of 13 N. The nanoengineering helps to achieve superior mechanical energy harvesting performance for GOCC compared to pristine CdS, which demonstrate the potential of nanogate structures to enhance the intrinsic properties of materials.10aGraphene oxide complex compound10aNanogate structure10aNew material10aNovel procedure10aPiezoelectric nanogenerator10aSLGO1 aKumar, Praveen1 aRam, Farsa1 aShanmuganathan, Kadhiravan1 aLuwang, Meitram, Niraj uhttps://library.ncl.res.in/content/cds-cubane-type-clusters-encapsulated-rolling-single-layer-reduced-graphene-oxide-sheets01762nas a2200169 4500008004100000022001400041245009600055210006900151260000800220300001600228490000700244520115100251100001501402700002001417700003101437856012401468 2022 eng d a0022-246100aNanocellulose/melanin-based composites for energy, environment, and biological applications0 aNanocellulosemelaninbased composites for energy environment and  cAUG a14188-142160 v573 a

Melanins, a class of brown-black pigments present in many natural sources, exhibit unique physical and chemical properties such as photoprotection, photoconductivity, metal ion chelation, free radical quenching, proton conductivity, and significant antimicrobial properties. These properties could be leveraged in various environmental and energy applications. However, their limited solubility makes them less amenable to processing. Over the last decade, there has been tremendous interest in developing synthetic analogs of melanin that are easy to dissolve and process. Nonetheless, melanins or their synthetic analogs cannot form mechanically robust free-standing films and fibers. This drawback could be partly circumvented by creating composites of melanin with nanocellulose, a nanomaterial derived from cellulosic biomass. Composites of melanins and nanocellulose offer an opportunity to utilize the functional aspects of melanin-like polymers in a mechanically stable nanocellulose network. This review attempts to capture the recent developments on this topic with special emphasis on technologically relevant applications.

1 aRam, Farsa1 aYadav, Prashant1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/nanocellulosemelanin-based-composites-energy-environment-and-biological-applications