@article { ISI:000228698900038, title = {PVA stabilized gold nanoparticles by use of unexplored albeit conventional reducing agent}, journal = {Materials Chemistry and Physics}, volume = {92}, number = {1}, year = {2005}, month = {JUL}, pages = {229-233}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Poly(vinyl alcohol) (PVA) stabilized gold nanoparticles have been prepared in aqueous medium using two different reducing viz.; hydrazine hydrate, a stronger reducing agent and sodium formaldehydesulfoxylate (SFS), a slightly weaker reducing agent. SFS is used for first ever time for reduction of gold metal salt. The PVA stabilized gold nanoparticles solutions are wine red to blood red coloured and are stable over a long period of time with no indication of aggregation. The solution shows strong visible light absorptions in the range of 520-540 nm, characteristics of gold nanoparticles. Powder X-ray diffraction patterns of freshly prepared films containing gold nanoparticles indicated particles size to be about 15 nm. Transmission electron microscopy (TEM) of a more than two-week-old sample revealed well-defined non-agglomerated spherical particles of about 50 nm diameter in solutions. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Chemical synthesis, electronic materials, Nanostructures, Polymer}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2005.01.016}, author = {Khanna, P. K. and Gokhale, R. and Subbarao, V. V. V. S. and Vishwanath, A. K. and Das, B. K. and Satyanarayana, C. V. V.} } @article { ISI:000266529600001, title = {Nanoscale particles for polymer degradation and stabilization-trends and future perspectives}, journal = {Progress in Polymer Science}, volume = {34}, number = {6}, year = {2009}, month = {JUN}, pages = {479-515}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The field of nanoscience and nanotechnology is extending the applications of physics, chemistry, biology, engineering and technology into previously unapproached infinitesimal length scales. The polymer-nanoparticles/nanocomposites have been the exponentially growing field of research for developing the materials in last few decades and have been mainly focusing on the structure-property relationships and their development. Since the polymer-nanocomposites have been the staple of modern polymer industry, their durability under various environmental conditions and degradability after their service life are also essential fields of research. Thus, this article is intended to review the status of worldwide research in this aspect. Among various nanoparticulates, clay minerals and carbon nanotubes are more often used in enhancing physical, mechanical and thermal properties of polymers. In very few systems, the nano particulates have been incorporated into polymer as {\textquoteleft}nano-additives{\textquoteright} for both purposes: degradation and stabilization of polymers. The degradation and durability of polymers is reviewed in the presence of nanoparticles/nanocomposites under different environmental conditions. Nanoparticle-induced biodegradation of polymers is also discussed. (c) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {Carbon nanotubes, clay, Degradation and stabilization, Nanocomposites, Nanoparticles, Polymer}, issn = {0079-6700}, doi = {10.1016/j.progpolymsci.2009.01.002}, author = {Kumar, Annamalai Pratheep and Depan, Dilip and Tomer, Namrata Singh and Singh, Raj Pal} } @article { ISI:000266520400034, title = {Polymer-embedded stannic oxide nanoparticles as humidity sensors}, journal = {Materials Science \& Engineering C-Biomimetic and Supramolecular Systems}, volume = {29}, number = {3}, year = {2009}, month = {APR}, pages = {847-850}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Stannic oxide (SnO(2)) nanoparticles have been suspended in polyvinyl alcohol (PVA) matrix in different PVA: SnO(2) molar ratios ranging from 1:1 to 1:5 using simple chemical route. This suspension was deposited on ceramic substrate and upon drying was carefully detached from the substrate. SnO(2)-embedded self-standing, transparent and flexible thin films were hence synthesized. Transmission electron microscopy (TEM) and Xray diffraction (XRD) techniques show the rutile tetragonal structure of SnO(2) with particle size similar to 5 nm. UV-Visible spectroscopy demonstrates the band gap of 3.9 eV, which does not alter when embedded in polymer. Fourier transform infrared spectroscopy (FTIR) reveals that the properties of SnO(2) do not modify due to incorporation in the PVA matrix. The structures work as excellent humidity sensors at room temperature. For a critical PVA:SnO(2) molar ratio of 1:3, the resistance changes to five times of magnitude in 92\% humidity within fraction of second when compared with resistance at 11\% humidity. The sample regains its original resistance almost instantaneously after being removed from humid chamber. Nanodimensions of SnO(2) particles and percolation mechanism related to transport through polymer matrix and water molecule as a carrier has been used to understand the mechanism. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {humidity sensor, Nanoparticles, Polymer, Stannic oxide}, issn = {0928-4931}, doi = {10.1016/j.msec.2008.07.039}, author = {Hatamie, Shadie and Dhas, Vivek V. and Kale, B. B. and Mulla, Imtiaz S. and Kale, Sangeeta N.} } @article { ISI:000312233600006, title = {Carbon nanoscrolls by pyrolysis of a polymer}, journal = {Solid State Communications}, volume = {152}, number = {23}, year = {2012}, month = {DEC}, pages = {2092-2095}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

3D network of carbon nanoscrolls was synthesized starting from pyrolysis of poly(acrylic acid-co-maleic acid) sodium salt. It is a catalyst-free process where pyrolysis of polymer leads to formation of carbon form and sodium carbonate. Upon water soaking of pyrolysis product, the carbon form undergoes self-assembly to form carbon nanoscrolls. The interlayer distance between the walls of carbon nanoscroll was found to be 0.34 nm and the carbon nanoscrolls exhibited a surface area of 188 m(2)/g as measured by the BET method. (c) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Carbon nanoscrolls, Polymer, Pyrolysis, supercapacitor}, issn = {0038-1098}, doi = {10.1016/j.ssc.2012.08.029}, author = {Yadav, Prasad and Warule, Sambhaji and Jog, Jyoti Prakash and Ogale, Satishchandra B.} } @article { ISI:000315306200009, title = {Effect of clay and of electrospinning on the polymorphism, structure and morphology of poly(vinylidene fluoride)}, journal = {European Polymer Journal}, volume = {49}, number = {1}, year = {2013}, month = {JAN}, pages = {90-99}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Electrospun poly(vinylidene fluoride) (PVDF) fibers, containing different amounts of montmorillonite clay were produced, in order to study the effect of clay and of the electrospinning process on the polymorphism, structure and morphology of the PVDF matrix, Clay acted as a processing aid agent, avoiding the formation of beads and improving the quality of the fibers. Clay and the electrospinning process acted synergically on the chain mobility, favoring the formation of beta phase of PVDF, the most valuable for its piezoelectric properties, and shaping its semicrystalline morphology. Electrospinning did not significantly aid the dispersion of clay within the matrix. The interplay of formulation and processing in these composites allowed to obtain PVDF-based materials with varying polymorphism, structure and morphology, offering the possibility to ultimately control their functional properties. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Composite, electrospinning, Poly(vinylidene fluoride), Polymer, polymorphism, SAXS}, issn = {0014-3057}, doi = {10.1016/j.eurpolymj.2012.09.023}, author = {Neppalli, Ramesh and Wanjale, Santosh and Birajdar, Mallinath S. and Causin, Valerio} } @article { ISI:000335706100026, title = {Comparison of polymer induced and solvent induced trypsin denaturation: the role of hydrophobicity}, journal = {Colloids and Surfaces B-Biointerfaces}, volume = {116}, year = {2014}, month = {APR}, pages = {201-205}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Trypsin adsorption from aqueous buffer by various copolymers of allyl glycidyl ether-ethylene glycol dimethacrylate (AGE-EGDM) copolymer with varying crosslink density increases with increasing crosslink density and the effect slowly wears off after reaching a plateau at 50\% crosslink density. The copolymer with 25\% crosslink density was reacted with different amines with alkyl/aryl side chains to obtain a series of copolymers with 1,2-amino alcohol functional groups and varying hydrophobicity. Trypsin binding capacity again increases with hydrophobicity of the reacting amine and a good correlation between logP(octanol) of the amine and protein binding is observed. The bound trypsin is denatured to the extent of 90\% in spite of the presence of hydrophilic hydroxyl and amino groups. The behavior was comparable to that in mixtures of aqueous buffer and water-miscible organic co-solvents where the solvent concentration required to deactivate 50\% of the enzyme (C-50) is dependent on logP(octanol) of the co-solvent. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Adsorption, Denaturation, Hydrophobicity, Polymer, Trypsin}, issn = {0927-7765}, doi = {10.1016/j.colsurfb.2014.01.002}, author = {Jasti, Lakshmi Swarnalatha and Fadnavis, Nitin W. and Addepally, Uma and Daniels, Siona and Deokar, Sarika Babasaheb and Ponrathnam, Surendra} } @article { ISI:000340975900071, title = {Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene)-few walled carbon nanotube (PEDOT-FWCNT) nanocomposite based thin films for Schottky diode application}, journal = {Materials Chemistry and Physics}, volume = {147}, number = {3}, year = {2014}, month = {OCT}, pages = {867-877}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Transparent, conductive films of poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene)-few walled carbon nanotube (PEDOT-FWCNT) nanocomposite were synthesized by in-situ oxidative polymerization and investigated for their Schottky diode property. The prepared films were characterized by UV-Vis spectroscopy, thermal gravimetric analysis (TGA), surface resistivity, cyclic voltametery, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). SEM reveals the formation of homogeneous and adhesive polymer films while HRTEM confirms the uniform wrapping of polymer chains around the nanotube walls for PEDOT-FWCNT film. Improved thermal stability, conductivity and charge storage property of PEDOT in the presence of FWCNT is observed. Among different compositions, 5 wt. \% of FWCNT is found to be optimum with sheet resistance and transmittance of 500 Omega sq(-1) and 77\%, respectively. Moreover, the electronic and junction properties of polymer films were studied and compared by fabricating sandwich type devices with a configuration of Al/PEDOT or PEDOT-FWCNT nanocomposite/indium tin oxide (ITO) coated glass. The measured current density-voltage characteristics show typical rectifying behavior for both configurations. However, enhanced rectification ratio and higher forward current density is observed in case of PEDOT-FWCNT based Schottky diode. Furthermore, reliability test depicts smaller hysteresis effect and better performance of PEDOT-FWCNT based diodes. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Composite materials, Electrical properties, Polymer, Thin films}, issn = {0254-0584}, doi = {10.1016/j.matchemphys.2014.06.032}, author = {Gupta, Bhavana and Mehta, Minisha and Melvin, Ambrose A. and Kamalakannan, R. and Dash, Sitaram and Kamruddin, M. and Tyagi, A. K.} } @article { ISI:000380625200002, title = {Immobilization of pectinase on reusable polymer support for clarification of apple juice}, journal = {Food and Bioproducts Processing}, volume = {99}, year = {2016}, month = {JUL}, pages = {12-19}, publisher = {INST CHEMICAL ENGINEERS}, address = {165-189 RAILWAY TERRACE, DAVIS BLDG, RUGBY CV21 3HQ, ENGLAND}, abstract = {

Pectinase (E.C.3.2.1.15) was successfully immobilized on recyclable polymer matrix. The immobilization matrix was prepared by reaction of polyethyleneimine (mol. wt. 70,000) with epoxy-activated acrylate copolymer DILBEAD-VWR. The enzyme pectinase was first adsorbed on the polymer at pH 7.0 via ion exchange and then stabilized by crosslinking with dextran aldehyde. While the free enzyme shows a pH-optimum of 5.0, the immobilized enzyme exhibited high level of activity in a broad pH range of pH 3.0-7.0. Although the thermal stability of free and immobilized enzymes was similar, at room temperature, the immobilized enzyme could be recycled more than 10 times with loss of less than 5\% of its activity during clarification of apple juice. On the eventual loss of enzyme activity, the immobilized enzyme and dextran aldehyde can be easily removed from the polymer by a simple treatment with 1N HCl and the polymer can be reused for immobilization of a fresh batch of enzyme. This support also can be reused several times, making the process economically attractive. The properties of apple juice treated with immobilized enzyme were similar to those of that treated with free pectinase. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

}, keywords = {Apple juice, Dextran aldehyde, Immobilization, Pectinase, Polyethyleneimine, Polymer}, issn = {0960-3085}, doi = {10.1016/j.fbp.2016.03.004}, author = {Rajdeo, Kishor and Harini, Tirunagari and Lavanya, Kuna and Fadnavis, Nitin W.} } @article {44240, title = {Interaction of polymers with amyloidogenic peptides}, journal = {Polymer International}, volume = {67}, year = {2018}, month = {JAN}, pages = {15-24}, type = {Article}, abstract = {

With this review, the aim was to gather recent representative publications which describe the interaction of polymers with amyloidogenic peptides/proteins. When functional, these take part in for instance bacterial adhesion and biofilm formation. However, several of the peptides/proteins have been identified in various diseases. One of the current approaches to discover a cure against these relies on therapeutics which either prevent or accelerate peptide/protein aggregation and/or clear readily formed aggregates. Owing to the common interest of scientists from all disciplines to identify a cure against the diseases of public health concern, there are overwhelming numbers of publications dealing with these two approaches. Since amyloid aggregation could be regarded as a nucleated polymerization, which is an established mechanism of polymer self-assembly, we recently tackled the issue of amyloid aggregation using the theories and methods established in polymer science. In this review, we hence focus on gathering relevant and recent publications which describe the role of polymers in modulating the aggregation of amyloidogenic peptides/proteins. (c) 2017 Society of Chemical Industry

}, keywords = {amyloid, neurodegenerative diseases, Polymer, protein, Self-assembly}, issn = {0959-8103}, doi = {10.1002/pi.5483}, author = {Abraham, Jancy Nixon and Nardin, Corinne} } @article {47173, title = {Comparative study of a class of mean field theories of the glass transition}, journal = {Journal of Statistical Mechanics-Theory and Experiment}, volume = {2019}, year = {2019}, month = {AUG}, pages = {084008}, type = {Article}, abstract = {

In a recently developed microscopic mean field theory, we have shown that the dynamics of a system, when described only in terms of its pair structure, can predict the correct dynamical transition temperature. Further, the theory predicted the difference in dynamics of two systems (the Lennard-Jones and the Weeks-Chandler-Andersen) despite them having quite similar structures. This is in contrast to the Schweizer-Saltzman (SS) formalism which predicted the dynamics of these two systems to be similar. The two theories although similar in spirit have certain differences. Here we present a comparative study of these two formalism to find the origin of the difference in their predictive power. We show that not only the dynamics in the potential energy surface, as described by our earlier study, but also that in the free energy surface, like in the SS theory, can predict the correct dynamical transition temperature. Even an approximate one component version of our theory, similar to the system used in the SS theory, can predict the transition temperature reasonably well. Interestingly, we show here that despite the above mentioned shortcomings the SS theory can actually predict the correct transition temperatures. Thus microscopic mean field theories of this class which express dynamics in terms of the pair structure of the liquid while being unable to predict the actual dynamics of the system are successful in predicting the correct dynamical transition temperature.

}, keywords = {aging, etc), glasses (colloidal, glassy dynamics, mode coupling theory, Polymer, slow relaxation}, issn = {1742-5468}, doi = {10.1088/1742-5468/ab3115}, author = {Saha, Indranil and Nandi, Manoj Kumar and Dasgupta, Chandan and Bhattacharyya, Sarika Maitra} } @article {46013, title = {Effect of electrostatic interactions on structure and mechanical properties of ice templated colloid-polymer composites}, journal = {Journal of Physics D-Applied Physics}, volume = {52}, year = {2019}, month = {MAY }, pages = {214002}, type = {Article}, abstract = {

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{\textquoteright}s isoelectric point. Correspondingly, we observe reduction in Young{\textquoteright}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.

}, keywords = {colloid, electrostatic interaction, ice templating, mechanical properties, Polymer}, issn = {0022-3727}, doi = {10.1088/1361-6463/ab0b7b}, author = {Suresh, Karthika and Kumaraswamy, Guruswamy} } @article {46938, title = {Study of interfacial adhesion between nickel-titanium shape memory alloy and a polymer matrix by laser surface pattern}, journal = {Applied Sciences-Basel}, volume = {10}, year = {2020}, month = {MAR}, pages = {2172}, type = {Article}, abstract = {

The aim of this article is to investigate the interfacial adhesion of Ni-Ti shape memory alloy with a polymer matrix of Poly (methyl methacrylate) (PMMA). The surface pattern on Ni-Ti plates was channeled by a solid state laser machine. The laser machine allows for creating channels on the Ni-Ti surface for infiltration of the PMMA matrix, which could be attached as an intra-surface locking pattern to the Ni-Ti surface. The influence of the PMMA matrix on the surface of the NiTi plate was evaluated by thermomechanical analysis (TMA) and dynamic mechanical analysis (DMA). The surface characterization was carried out by an optical microscope on the PMMA/NiTi composite after mechanical testing. During mechanical testing, the polymer displays the multiple cracks in the longitudinal direction that result in slipping and fracture. TMA and DMA analyses were performed on the Ni-Ti- and PMMA-coated Ni-Ti ribbon to observe elasticity and the storage modulus for both samples. Better adhesion than 80 \% was observed in the Ni-Ti surface, in the laser surface pattern, in comparison to the free plain surface. However, the polymer acts as mechanical backing that caused a reduction in the shape-memory properties of the composite material.

}, keywords = {adhesion, mechanical properties, NiTi composites, NiTi plate, PMMA, Polymer, surface features}, doi = {10.3390/app10062172}, author = {Samal, Sneha and Tyc, Ondrej and Heller, Ludek and Sittner, Petr and Malik, Monika and Poddar, Pankaj and Catauro, Michelina and Blanco, Ignazio} } @article {47087, title = {Design and synthesis of a new topical agent for halting blood loss rapidly: a multimodal chitosan-gelatin xerogel composite loaded with silica nanoparticles and calcium}, journal = {Colloids and Surfaces B-Biointerfaces}, volume = {198}, year = {2021}, month = {FEB}, pages = {111454}, type = {Article}, abstract = {

Uncontrolled hemorrhage often causes death during traumatic injuries and halting exsanguination topically is a challenge. Here, an efficient multimodal topical hemostat was developed by (i) ionically crosslinking chitosan and gelatin with sodium tripolyphosphate for (ii) fabricating a robust, highly porous xerogel by lyophilization having 86.7 \% porosity, by micro-CT and large pores similar to 30 mu m by SEM (iii) incorporating 0.5 mg synthesized silica nanoparticles (SiNPs, 120 nm size, -22 mV charge) and 2.5 mM calcium in xemgel composite that was confirmed by FTIR analysis with peaks at 3372, 986 and 788 cm(-1), respectively. XPS analysis displayed the presence of SiNPs (Si2p peak for silicon) and calcium (Ca2p1, Ca2p3 transition peaks) in the composite. Interestingly, in silico percolation simulation for composite revealed interlinked 800 mu m long-conduits predicting excellent absorption capacity and validated experimentally (640 \% of composite dry weight). The composite achieved \>16-fold improved blood clotting in vitro than commercial Celox and Gauze through multimodal interaction of its components with RBCs and platelets. The composite displayed good platelet activation and thrombin generation activities. It displayed high compressive strength (2.45 MPa) and withstood pressure during application. Moreover, xerogel composite showed high biocompatibility. In vivo application of xerogel composite to lethal femoral artery injury in rats achieved hemostasis (2.5 min) significantly faster than commercial Celox (3.3 min) and Gauze (4.6 min) and was easily removed from the wound. The gamma irradiated composite was stable till 1.5 yr. Therefore, the xerogel composite has potential for application as a rapid topical hemostatic agent.

}, keywords = {Hemostatic, Polymer, silica nanoparticles, Xerogel}, issn = {0927-7765}, doi = {10.1016/j.colsurfb.2020.111454}, author = {Patil, Gokul and Torris, Arun and Suresha, P. R. and Jadhav, Sachin and Badiger, V. Manohar and Ghormade, Vandana} } @article {48115, title = {Composition and surface morphology invariant high on-off ratio from an organic memristor}, journal = {ACS Applied Electronic Materials}, volume = {4}, year = {2022}, month = {MAR }, pages = {1109-1116}, type = {Article}, abstract = {

Material composition plays a crucial role in the device performance; thus, nonvolatile memory devices from a small molecule named 5-mercapto-1-methyl tetrazole (MMT) in an insulating polymer matrix of poly(4-vinyl pyridine) (PVP) were fabricated. The composition of the active material in the device was varied to observe its influence on the device{\textquoteright}s electronic properties. The device with a more or less weight ratio of MMT has a much smoother surface morphology, whereas when the contributions of MMT and PVP were equal, the average surface roughness increased. However, the maximum on-off current ratio for all the devices is 10(5), suggesting that the MMT molecule does not show any change in its characteristic properties when surrounded by an insulating material. When the device was fabricated without the polymer matrix, the surface morphology of the device completely changed as it was filled with large holes. These holes provide short-circuited pathways for the current by forming the direct metal contact between the top and bottom electrodes. The carrier transport through these devices follows various conduction mechanisms. Some of the dominating conduction mechanisms are direct tunneling and trap-free and trap-assisted space-charge-limited conduction.

}, keywords = {Nonvolatile memory, Polymer, small molecule, space-charge, tunneling}, doi = {10.1021/acsaelm.1c01234}, author = {Betal, Atanu and Bera, Jayanta and Sharma, Ashish and Rath, Arup K. and Sahu, Satyajit} }