01821nas a2200193 4500008004100000022001400041245011000055210006900165260007100234300001600305490000800321520104600329100002501375700002301400700001701423700003001440700002701470856013001497 2013 eng d a1520-610600aExclusion from hexagonal mesophase surfactant domains drives end-to-end enchainment of rod-like particles0 aExclusion from hexagonal mesophase surfactant domains drives end a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a12661-126680 v1173 a

Anisotropic rod-like particles assemble end-to-end when the surfactant/water matrix in which they are dispersed is cooled from the isotropic to the lyotropic hexagonal phase. We demonstrate the formation of such end-to-end assemblies for gold nanorods, which are tens of nanometers in size, as well as for micrometer-sized ellipsoidal polystyrene particles. In both cases, the particles are well-dispersed in the low-viscosity surfactant/water phase above the isotropic-H-1 transition temperature. On cooling into the H-1 phase, mesophase domains form and the particles are expelled to the isotropic phase. As the H-1 domains grow and finally impinge, the particles are localized at the domain boundaries where they reorient and assemble end-to-end. Remarkably, we observe the formation of end-to-end assemblies of gold nanorods even for volume fractions as low as 2 x 10(-6) in the initially dispersed state. The extent of particle ``enchainment'' increases with the particle concentration and with the aspect ratio of the particles.

1 aSharma, Kamendra, P.1 aGanai, Anal, Kumar1 aSen, Debasis1 aPrasad, Bhagavatula L. V.1 aKumaraswamy, Guruswamy uhttp://library.ncl.res.in/content/exclusion-hexagonal-mesophase-surfactant-domains-drives-end-end-enchainment-rod-particles-001687nas a2200265 4500008004100000022001400041245009100055210006900146260007100215300001600286490000600302520077300308653001901081653001401100653002601114653001701140653001701157100002101174700002301195700002101218700002401239700002701263700001701290856011401307 2014 eng d a1944-824400aEnhancing cubosome functionality by coating with a single layer of poly-epsilon-lysine0 aEnhancing cubosome functionality by coating with a single layer  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a17126-171330 v63 a

We report the preparation and characterization of monoolein cubosomes that can be easily surface modified through adsorption of a single layer of cationic poly-epsilon-lysine. Poly-epsilon-lysine coated cubosomes show remarkable stability in serum solution, are nontoxic and, are readily internalized by HeLa cells. The poly-epsilon-lysine coating provides chemical handles for further bioconjugation of the cubosome surface. We also demonstrate that the initial release rate of a hydrophilic drug, Naproxen sodium, from the cubosomes is retarded with just a single layer of polymer. Interestingly, cubosomes loaded with Naproxen sodium, recently shown to have anticancer properties, cause more apoptosis in HeLa cells when compared to free unencapsulated drug.

10abioconjugation10acubosomes10adrug delivery vehicle10adual loading10atheranostics1 aDeshpande, Sonal1 aVenugopal, Edakkal1 aRamagiri, Shobha1 aBellare, Jayesh, R.1 aKumaraswamy, Guruswamy1 aSingh, Neetu uhttp://library.ncl.res.in/content/enhancing-cubosome-functionality-coating-single-layer-poly-epsilon-lysine-002475nas a2200169 4500008004100000245010500041210006900146260000800215300001400223490000800237520182600245100001902071700002802090700002702118700003102145856012902176 2017 eng d00aElastic compressible energy storage devices from ice templated polymer gels treated with polyphenols0 aElastic compressible energy storage devices from ice templated p cFEB a3270-32780 v1213 aDesign and fabrication of rechargeable energy storage devices that are robust to mechanical deformation is essential for wearable electronics. We report the preparation of compressible supercapacitors that retain their specific capacitance after large compression and that recover elastically after at least a hundred compression expansion cycles. Compressible supercapacitors are prepared using a facile, scalable method that readily yields centimeter-scale macroporous objects. We ice template a solution of polyethylenimine in green tea extract to prepare a macroporous cross-linked polymer gel (PG) whose walls are impregnated with green tea derived polyphenols. As the PG is insulating, we impart conductivity by deposition of gold on it. Gold deposition is done in two steps: first, silver nanoparticles are formed on the PG walls by in situ reduction by polyphenols and then gold films are deposited on these walls. Gold coated PGs (GPGs) were used as electrodes to deposit poly(3,4-ethylenedioxythiophene) as a pseudocapacitive material. The specific capacitance of PEDOT coated GPGs (PGPG) was found to be 253 F/g at 1 A/g. PGPG could be compressed and expanded over a hundred cycles without any suffering mechanical failure or loss of capacitative performance. The capacitance was found to be 243 F/g upon compressing the device to 25% of its original size (viz. compressive strain = 75%). Thus, even large compression does not affect the device performance. This device shows power and energy densities of 2715 W/kg and 22 Wh/kg, respectively, in the uncompressed state. The macroporous nature of PGPG makes it possible to fill the PGPG pores with gel electrolyte. We report that the gel electrolyte filled supercapacitor exhibited a specific capacitance of 200 F/g, which increased by 4% upon 75% compression.1 aDas, Chayanika1 aChatterjee, Soumyajyoti1 aKumaraswamy, Guruswamy1 aKrishnarnoorthy, Kothandam uhttp://library.ncl.res.in/content/elastic-compressible-energy-storage-devices-ice-templated-polymer-gels-treated-polyphenols02649nas a2200217 4500008004100000022001400041245012400055210006900179260000900248300001100257490000700268520187900275653001202154653003002166653001902196653002602215653001202241100002102253700002702274856013002301 2019 eng d a0022-372700aEffect of electrostatic interactions on structure and mechanical properties of ice templated colloid-polymer composites0 aEffect of electrostatic interactions on structure and mechanical cMAY  a2140020 v523 a

When an aqueous dispersion of negatively charged colloids, cationic polymer and crosslinker is frozen and the polymer is allowed to crosslink in the frozen state, we obtain a self-standing macroporous composite foam. This material is soft, despite the high concentration of colloids and yet is remarkably elastic to large compressive strains. In these macroporous composites, the pore walls comprise colloidal particles held within a crosslinked polymer network. Here, we investigate the effect of varying colloid- polymer interactions in pre-fabricated macroporous composites on their microstructure and mechanical properties. During preparation of the composite, cationic polymer adsorbs on the negatively charged colloids. We tune the surface charge of particles embedded in a macroscopic monolith by immersing the composites in water maintained at different pH. In this way, we tune polymer-particle interactions in the composite. We observe a sudden increase in interparticle distance and swelling of composite when pH is decreased below the particle's isoelectric point. Correspondingly, we observe reduction in Young's and shear moduli, compression strength and macroscopic energy dissipation. We did not observe any pH dependent changes in pure polymer sponges (prepared by ice templating and crosslinking a polymer solution that does not contain colloidal particles). Therefore, the pH dependent structural and mechanical property changes arise from the composite structure rather than purely from the crosslinked polymer. We believe that the reduction in mechanical stiffness when the polymer-particle interaction becomes repulsive is because of the reduction in interfacial contacts between particle and polymer. Therefore, the mechanical stiffness of ice templated composite is strongly influenced by interactions between the polymer and particle surface.

10acolloid10aelectrostatic interaction10aice templating10amechanical properties10aPolymer1 aSuresh, Karthika1 aKumaraswamy, Guruswamy uhttp://library.ncl.res.in/content/effect-electrostatic-interactions-structure-and-mechanical-properties-ice-templated-colloid02151nas a2200253 4500008004100000022001400041245015200055210006900207260000800276300001400284490000700298520126500305653001201570653001601582653002701598653002201625653002101647100001501668700001801683700001701701700002701718700003101745856012101776 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 uhttp://library.ncl.res.in/content/elastic-piezoelectric-aerogels-isotropic-and-directionally-ice-templated-cellulose