Atul Kapil - Academia.edu (original) (raw)

Papers by Atul Kapil

Colloid and Polymer Science, 2012

Poly(N-isopropylacrylamide)-grafted polystyrene/ poly(styrene-co-4-vinylbenzyl N, N-diethyldithio... more Poly(N-isopropylacrylamide)-grafted polystyrene/ poly(styrene-co-4-vinylbenzyl N, N-diethyldithiocarbamate) [PNIPAM-grafted PS/P(St-co-VBDC)] hairy particles were synthesized by photo-polymerizing N-isopropylacrylamide monomer in the presence of PS/P(St-co-VBDC) core particles. Here, the VBDC unit, which was incorporated into the surface of core particles by seeded soap-free emulsion copolymerization, acted as a photo-iniferter. By varying the polymerization conditions, a series of hairy particles having different grafting heights and grafting densities was successfully obtained. The hairy particles exhibited well-defined core/ shell morphology. PS/P(St-co-VBDC) formed the core which was surrounded by PNIPAM shell. The determination of critical coagulation concentration (CCC) indicated that the hairy particles were stabilized via both electrostatic and steric mechanisms (i.e., electrosteric mechanism) at a temperature lower than LCST of PNIPAM. However, these particles gave much lower CCCs when heated to the temperature higher than LCST, exhibiting temperature-dependent colloidal stability.

International Journal of Recent Technology and Engineering, 2019

Para-toluenesulphonic acid doped Poly(2-methylaniline) (PmANI) was synthesized by chemical method... more Para-toluenesulphonic acid doped Poly(2-methylaniline) (PmANI) was synthesized by chemical method using ammoniumpersulphate (APS) as an oxidant. It was synthesized along with optimization studies w.r.t. varied dopant-monomer ratios for better DC conductivity. Various spectroscopies like XRD, UV-Vis and FT-IR were used to characterize the polymer. The behavior of DC conductivity with variation in temperature was studied with in the temperature range of 300 - 425 K and it was observed that conductivity rised to ~four orders with the surge in temperature. The experimental conductivity data was fitted with various conduction models to find the proper charge transport mechanism in this polymer.

Polyaniline doped with p-toluenesulfonic acid was synthesized with chemical oxidation method by v... more Polyaniline doped with p-toluenesulfonic acid was synthesized with chemical oxidation method by varying synthesis parameters. We report the electrical conductivity study of polyaniline doped with p- toluenesulfonic acid in the temperature range of 10 K to 300 K. The conductivity of the samples has been observed to show an increasing trend with increase in temperature. The Arrhenius model, variable range hopping (VRH), and Kivelson model were used to investigate the charge transfer in polyaniline. It has been shown that no one mechanism can completely describe the charge transport in polyaniline over entire temperature range 10 K- 300 K.

Solid State Communications, 2010

Polypyrrole was synthesized by the chemical oxidation method in the presence of phosphoric acid b... more Polypyrrole was synthesized by the chemical oxidation method in the presence of phosphoric acid by varying oxidant to monomer molar ratio for the optimization of electrical conductivity. The conductivity in doped polypyrrole reached up to a maximum value of 9.18 S/cm. Granular morphology was observed in chemically synthesized polypyrrole. Neutralization of doped polypyrrole was done with aqueous ammonium hydroxide and three orders of reduced conductivity were obtained in neutral polypyrrole. Doped and undoped samples of polypyrrole were then electrically characterized over a wide temperature range of 10-300 K. The measured electrical conductivity rises with the increase in temperature and shows the semiconducting nature of the material. Strong and weak temperature dependence of conductivity was revealed by undoped and doped polypyrrole samples respectively. An effort has been made to explore the electrical transport in doped and undoped polypyrrole by charge transport models. The experimental data obeys Kivelson's hopping model in temperature range of 60-300 K and fluctuation assisted tunneling was the dominant conduction mechanism below 60 K.

Journal of Materials Science: Materials in Electronics, 2010

Polypyrrole (PPy) is polymerized by chemical oxidative polymerization in presence of anionic surf... more Polypyrrole (PPy) is polymerized by chemical oxidative polymerization in presence of anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (DEHS) as the dopant. The electrical conductivity was optimized in terms of oxidant to monomer molar ratio and polymerization yield was measured for these reactions. We have used ammonium persulphate (APS) as the oxidant for polymerization in this series of experiments. The effect of concentration of oxidant on the electrical conductivity is examined. Chemical synthesis of polypyrrole is supported by FTIR spectrum. The electrical conductivity of doped and undoped polypyrrole has been measured in the temperature range of 10-300 K and is found to increase with rise in temperature. Electrical conductivity of PPy was analyzed in the light of various charge transport models. Analysis of the electrical conductivity data reveals that in the temperature range 60-300 K electrical transport is predominantly governed by power law behaviour given by Kivelson model. However in the low temperature range 10-60 K electrical transport is dominated by the fluctuation assisted mechanism.

Journal of Electronic Materials, 2011

Abstract Poly (N-methylaniline)(PNMA) doped with p-toluenesulfonic acid (PTSA) was prepared chemi... more Abstract Poly (N-methylaniline)(PNMA) doped with p-toluenesulfonic acid (PTSA) was prepared chemically. Polymer synthesis was optimized for different dopant-to-monomer and oxidant-to-monomer ratios. The polymer was characterized by Fourier-transform infrared ( ...