@article { ISI:000235860500014, title = {Electron beam induced surface cross-linking of functional monomers coated on silicon substrate}, journal = {Materials Letters}, volume = {60}, number = {11}, year = {2006}, month = {MAY}, pages = {1360-1365}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A 3: 1 composition of functional monomer: multifunctional acrylate was spin coated and later cross-linked under the influence of keV electron irradiation on the surface of silicon to generate a surface-anchored cross-linked network bearing functional moieties. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) as well as wetting angle measurements were used for the analysis of functional monomer cross-linked surfaces. Results of the surface reconstruction of surfaces and electron irradiated on coated silicon wafers reveal that long-term hydrophilic surfaces can be achieved. Thus, the surface architecture can be favorably manipulated by using this remarkable technique with a Suitable combination of functional monomers and cross-linkers. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {electron beam irradiation, FTIR, Polymers, surface modification, XPS}, issn = {0167-577X}, doi = {10.1016/j.matlet.2005.11.029}, author = {Mahapatra, S. K. and Bodas, Dhananjay S. and Mandale, A. B. and Gangal, S. A. and Bhoraskar, Vasant N.} } @article { ISI:000248062700019, title = {Exhaustive analysis of frontal copolymerization of functionalized monovinyl and divinyl monomers}, journal = {Chemistry-A European Journal}, volume = {13}, number = {20}, year = {2007}, month = {APR}, pages = {5862-5872}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A series of copolymers of 2-hydroxyethyl methacrylate (HEMA)/ glycidyl methacrylate (GMA) and ethylene dimethacrylate (EGDM) were synthesized by frontal polymerization (FP). This study was conducted to investigate the effect of crosslink density, type and concentration of initiator, the use of a complex initiator system, porogen, and diluent on the most relevant parameters of FP, such as sustainability of the front, temperature profile, front velocity, and yield. The products were also characterized for intruded pore volume, pore-size distribution, epoxy-functionality number, and surface morphology. Higher crosslink densities (CLDs) and initiator concentration produced higher front velocities, whereas no trend in front temperature was noted. A complex initiation system was effective in stabilizing and increasing the polymerization yield. Relative to suspension polymerization (SP), FP products synthesized without a solvent were microporous, whereas micro-to-macroporous products were obtained in the presence of a solvent (for HEMA-EGDM polymers). We also present, explain, and discuss the exotic patterns observed under a microscope. We observed two basic types of spatial patterns, namely, planar and nonplanar patterns. The type of planar pattern observed under scanning electron microscopy (SEM) has a spatial impulse that appears as a loop followed by regular periodic motion in the radial and axial directions. This behavior gives rise to a repeating pattern that is a few microns thick. Also, nonplanar patterns, namely, layered concentric rings and winding staircase patterns, were observed under SEM.

}, keywords = {copolymerization, patterns, Polymers, porosity}, issn = {0947-6539}, doi = {10.1002/chem.200601428}, author = {Pujari, Narahari S. and Inamdar, Satish R. and Ambekar, Jalindar D. and Kulkarni, B. D. and Ponrathnam, Surendra} } @article { ISI:000254869800024, title = {Polymer electrolyte fuel cells using nafion-based composite membranes with functionalized carbon nanotubes}, journal = {Angewandte Chemie-International Edition}, volume = {47}, number = {14}, year = {2008}, month = {FEB}, pages = {2653-2656}, publisher = {WILEY-V C H VERLAG GMBH}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, keywords = {fuel cells, membranes, nanotubes, Polymers, proton transport}, issn = {1433-7851}, doi = {10.1002/anie.200704343}, author = {Kannan, Ramaiyan and Kakade, Bhalchandra A. and Pillai, Vijayamohanan K.} } @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 { ISI:000283759400011, title = {Polyethersulfone-expanded graphite nanocomposites: charge transport and impedance characteristics}, journal = {Composites Science and Technology}, volume = {70}, number = {14}, year = {2010}, month = {NOV0}, pages = {2111-2116}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Polyethersulfone (PES)-expanded graphite nanocomposites have been prepared by solution blending route after sonicating expanded graphite in dichloromethane. It has been observed that ultrasonication results in nanosheets formation leading to a low percolation threshold of 3 wt.\%. At 5 wt.\% filler loading the conductivity is of the order of 10(-2) S/cm. Hopping type of charge transport occurs at 3.2 wt.\% expanded graphite in PES below which capacitive effects couple. The effective dielectric constant at low frequency increases with filler concentration. Impedance measurement has been carried out to evaluate interfacial capacitance which, for 3.2 wt.\% expanded graphite addition in PES, increases to 110 pF from 32 pF for 1 wt.\% expanded graphite in the polymer. DSC analysis shows an increment of 12 C in the T(g) of PES with 3 wt.\% expanded graphite suggesting interaction between the polymer and filler. (C) 2010 Elsevier Ltd. All rights reserved.

}, keywords = {Differential scanning calorimetry (DSC), Electrical properties, Modeling, Polymers, Scanning/transmission electron microscopy (STEM)}, issn = {0266-3538}, doi = {10.1016/j.compscitech.2010.08.008}, author = {Ramanujam, B. T. S. and Mahale, Rajashree Y. and Radhakrishnan, S.} } @article { ISI:000292118800013, title = {Morphological changes in nanoparticulate silver films due to electron beam irradiation of polystyrene substrates}, journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions With Materials and Atoms}, volume = {269}, number = {13}, year = {2011}, month = {JUL}, pages = {1534-1539}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Results of the studies on the effect of 8 MeV electron beam irradiation of polystyrene substrates on the morphology of silver particulate films deposited at 455 K in a vacuum of 8 x 10(-6) Torr are reported. Optical absorption studies show the presence of transverse and longitudinal plasmon resonance for films deposited on irradiated polystyrene. Scanning electron microscopy reveals a decrease in particle size with smaller inter-particle separation for irradiated films. Larger clusters are formed in the case of films deposited on polystyrene after 300 h of irradiation. In this paper, we show that the morphology of silver nanoparticulate films can be modified by electron irradiation of inert polymer substrates like polystyrene. The change observed due to irradiation is attributed to the formation of free radicals, thereby altering the polymer-metal interaction. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Electron bombardment, Optical properties, Particulate films, Polymers, Silver, surface morphology}, issn = {0168-583X}, doi = {10.1016/j.nimb.2011.04.109}, author = {Pattabi, Manjunatha and Gurumurthy, S. C. and Sanjeev, Ganesh and Gaikwad, A. B.} } @article { ISI:000340330500055, title = {Modeling chain-end scission using the fixed pivot technique}, journal = {Chemical Engineering Science}, volume = {116}, year = {2014}, month = {SEP}, pages = {601-610}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Chain-end scission of polymer molecules is the breakage of a fixed-size oligomer or monomer from either end of the macromolecule. A common example is the generation of the glucose monomer from the hydrolysis of starch by glucoamylase. Modeling the dynamics of chain-end scission from first principles by considering each molecular size is challenging due to the large number of differential equations to be solved. The Population Balance Modeling (PBM) is a helpful framework as it could be formulated to lump a few molecular sizes together. However, it is then not obvious how to accurately account for the temporal evolution of the low molecular weight species, which is often of the greatest industrial interest. Here, the Fixed Pivot (FP) technique - one of the methods to solve PBM equations was appropriately modified to address this difficulty. By treating the lower molecular size range as a discrete domain in conjunction with a continuous domain in the upper ranges, the modified FP technique not only retains its original strengths, but also captures accurately the distribution of oligomers including the monomer. The results, which were obtained at a fraction of computational expense, benchmarked very well against the exact solutions for a polymer with a broad size distribution at different Degrees of Polymerization up to similar to O(10(5)). To facilitate wider adoption, guidelines on choice of pivots and observations of the performance of the modified FP technique are also deliberated. (C) 2014 Elsevier Ltd. All rights reserved.

}, keywords = {Chain-end scission, Fixed Pivot, Polymers, Population balance}, issn = {0009-2509}, doi = {10.1016/j.ces.2014.05.035}, author = {Ho, Yong Kuen and Doshi, Pankaj and Yeoh, Hak Koon and Ngoh, Gek Cheng} } @article { ISI:000343819200016, title = {Nature of the active site in ziegler-natta olefin polymerization catalysis systems - a computational investigation}, journal = {European Journal of Inorganic Chemistry}, number = {29}, year = {2014}, month = {OCT}, pages = {5063-5076}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Pull quantum chemical calculations with density functional theory (DET) show that a principal role of donors in Ziegler-Nana (ZN) oh-din polymerization catalysts is to coordinate to the metal center at the active sites on the MgCl2 surface. Thereby, the behavior of the catalyst is modulated to favor insertion over termination and, thus, polymerization occurs. This is shown to be true for a range of different donors. The calculations indicate that active sites that feature anionic chloride ligands at the titanium center (the conventional model for the active site) would lead to lower-molecular-weight riolymers. If an -OC2H5 group were present instead of a chloride ligand, the active site would much more effectively produce long chain polymers. Therefore, the current work provides important new insights into the nature of the ZN polymerization process.

}, keywords = {Alkene polymerization, Density functional calculations, heterogeneous catalysis, Insertion, Polymers}, issn = {1434-1948}, doi = {10.1002/ejic.201402180}, author = {Kumawat, Jugal and Gupta, Virendra Kumar and Vanka, Kumar} } @article {43792, title = {Synthesis, characterization and electrochemical investigations of mixed-ligand copper(II)-organic supramolecular frameworks}, journal = {Journal of Molecular Structure}, volume = {1147}, year = {2017}, month = {NOV}, pages = {549-557}, type = {Article}, abstract = {

Two mixed-ligand copper(II)-organic coordination compounds with 5,5{\textquoteright}-dimethyl-2,2{\textquoteright}-bipyridine (5,5{\textquoteright}-Me(2)bpy) as a primary ligand while aliphatic malonate (Hmal) and aromatic 2-hydroxynicotinate (2-OHNA) as secondary ligands, were synthesized. These complexes are formulated as: [Cu(Hmal)(5,5{\textquoteright}-Me(2)bPY)(H2O)](ClO4) 1 and [Cu-2(2-OHNA)(2)(5,5{\textquoteright}-Me(2)bpy)(2)(NO3)KNO3) 2. These two complexes were structurally characterized by single crystal X-ray diffraction analysis. Characterization was further supported by powder X-ray diffraction analysis, elemental analyses, FT-IR, FAB-MASS and TGA, DSC studies. Cyclic voltammetric and UV-visible spectral studies of these two complexes have also been done. The electrochemical studies of complex 1 in DMSO and DMF have shown that this complex undergoes quasi reversible diffusion-controlled one-electron transfer reaction without any chemical complication while complex 2 in DMSO undergoes quasi-reversible diffusion-controlled one electron transfer reaction, following EC mechanism. The electrochemical behaviour of complex 2 in DMF is complicated probably due to presence of more than one species in solution phase. (C) 2017 Elsevier B.V. All rights reserved.

}, keywords = {2 {\textquoteright}-bipyridine, 3, 5, 5 {\textquoteright}-dimethyl-2, 5-Tricarboxylic acid, Benzene-1, classification, Co-ordination-Compounds, Crystal-structures, cyclic voltammetry, magnetic properties, metal organic framework, Mixed-ligand complex, pi-pi stacking interaction, Polymers, Secondery Building Unit, Structural data, Supramolecular framework, Ternare Komplexe, X-ray diffraction}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2017.06.128}, author = {Singh, Sandeep K. and Srivastava, Ashish Kumar and Srivastava, Krishna and Banerjee, Rahul and Prasad, Jagdish} } @article {43901, title = {Thermotropic liquid crystalline polyesters derived from 2-chloro hydroquinone}, journal = {Journal of Chemical Sciences}, volume = {129}, year = {2017}, month = {SEP}, chapter = {1461-1468}, abstract = {

Synthesis of thermotropic liquid crystalline polyesters derived from bis[4-hydroxy benzoyloxy]-2-chloro-1,4-benzene (BHBOCB) and aliphatic dicarboxylic acid chlorides by interfacial polycondensation methodology is presented. Synthesised polyesters consist of bis[4-hydroxy benzoyloxy]-2-chloro-1,4-benzene as a mesogen and aliphatic diacid chloride as flexible spacer. The length of oligomethylene units in the polymer was varied from the trimethylene to the dodecamethylene groups. Synthesized polyesters were characterized by differential scanning calorimetry and optical microscopy. The transition temperatures and thermodynamic properties were studied for all these polymers. These polyesters exhibited thermotropic liquid crystalline behavior and showed nematic texture except decamethylene spacer. Decamethylene spacer based polyester showed marble texture of smectic C. Mesophase stability of these polyesters was higher than (except first heating cycle of PE-1).\ 

SYNOPSIS The present study deals with the synthesis of thermotropic liquid crystalline polyesters derived from bis[4-hydroxy benzoyloxy]-2-chloro-1,4-benzene (BHBOCB) and aliphatic dicarboxylic acid chlorides by interfacial polycondensation methodology.

}, keywords = {acid, Aliphatic Flexible Spacers Main-chain, Aromatic Mesogen, Elastomer, Morphology, Polydomain, Polymers, Thermotropic Liquid Crystalline Polyesters, Units}, doi = {10.1007/s12039-017-1342-y}, author = {Manurkar, Nagesh and More, Sayaji and Mulani, Khudbudin and Ganjave, Nitin and Chavan, Nayaku} } @article {44519, title = {Surface modification of polymers for tissue engineering applications: arginine acts as a sticky protein equivalent for viable cell accommodation}, journal = {ACS Omega}, volume = {3}, year = {2018}, month = {APR }, pages = {4242{\textendash}4251}, type = {Journal Article}, abstract = {

Hydrophobic polymers, for their favorable mechanical properties, are a popular choice as permanent bioimplants. These materials remain absolutely bioinert for years, but throw up challenges when it comes to fast integration with healthy tissue. Addressing this, herein, we present a surface-modification technique of converting the hydrophobic surface of a polymeric film into a hydrophilic one using a layer-by-layer assembly process involving gold nanoparticles and small molecules like amino acids. These films showed much improved animal cell (murine fibroblast) adherence properties compared to commercially available tissue culture plates. Moreover, arginine-modified films exhibited a nearly equivalent cell viability compared to the films modified with the natural extracellular matrix component fibronectin. The surface hydrophilicity and roughness of our novel film were characterized by contact angle measurement and atomic force microscopy. Cell counting, fluorescence microscopy, cell viability, and collagen estimation assay were employed to demonstrate that our film favored a much improved cell adherence, and accommodation in comparison to the commercially available tissue culture plates.

}, keywords = {Cell and Molecular biology, Extracellular matrix proteins, Nanoparticles, Physical and chemical properties, Polymers, Proteins, Surface structure, Surface treatment, Thin films, tissue engineering}, issn = {24701343}, doi = { 10.1021/acsomega.8b00215}, author = {Sengupta, Poulomi}, editor = {Prasad, Bhagavatula L. V.} } @article {46924, title = {Glass transition temperature of polybutadiene and polyisoprene from high temperature segmental relaxation correlation using molecular dynamics}, journal = {Soft Materials}, volume = {18}, year = {2020}, month = {JUL }, pages = {290-296}, type = {Article}, abstract = {

Predicting glass transition temperature for rubber and rubber composites is immensely important for tire industry for the development of products and fine-tune process conditions. Molecular dynamics simulation is been used to predict glass transition temperature as a function of molecular-level structural changes, e.g., composition (functional groups), topology, and polymerization. However, prediction of glass transition temperature within experimental error bar from molecular dynamics simulation is only possible from all atomistic description (model) of the system as united atom and coarse-grained models under-predict the values. Conventional way of calculation of glass transition temperature from density (or any other properties which show sharp transition)-temperature plots are computationally very demanding because of atomistic simulations and simulations below the glass transition point, i.e., in glassy state. Here we report a novel method for calculation of glass transition temperature using only segmental relaxation correlation functions calculated at higher temperatures, i.e., above glass transition temperature. We have presented a protocol here and shown for two polymeric systems polybutadiene and polyisoprene. We believe this method cuts the computational cost of predicting glass transition temperature by one-third and will be applicable for industrial applications for structure-property validations.

}, keywords = {Glass transition temperature, molecular dynamics simulation, Polymers, rubber}, issn = {1539-445X}, doi = {10.1080/1539445X.2020.1739709, Early Access Date = MAR 2020}, author = {Sharma, Pragati and Roy, Sudip} }