Neelotpal Sen Sarma
Articles written in Bulletin of Materials Science
Volume 37 Issue 7 December 2014 pp 1613-1624
This work reports the achievement of higher proton conductivity of polystyrene based proton exchange membrane synthesized in a continuous RF plasma polymerization process using two precursors, styrene (C8H8) and trifluoromethane sulfonic acid (CF3SO3H). The chemical composition of the developed membranes is investigated using Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Scanning electron microscopy has been used for the study of surface morphology and thickness measurement of the membrane. The membranes deposited in the power range from 0.114 to 0.318 Wcm-2 exhibit a lot of variation in the properties like proton transport, water uptake, sulfonation rate, ion exchange capacity and thermal behaviour. The proton conductivity of the membranes is achieved up to 0.6 Scm-1, measured with the help of potentiostat/galvanostat. The thermogravimetric study of the plasma polymerized membrane shows the thermal stability up to 140 °C temperature.
Volume 38 Issue 3 June 2015 pp 797-803
The synthesis, characterization and improved ionic conductivities of the salts of poly-(2-vinylpyridine) with crotonic acid and vinyl acetic acid are reported here. In this study, the alternating current conductivity measurements were carried out within the temperature range of 30–90° C and the frequency range of 1 Hz–100 kHz in solid state. A two- to three-fold increase in conductivity was observed for vinyl acetic acid salt whereas one- to twofold increase was observed for crotonic acid salt. The ionic transport numbers of the salts were measured with the help of the Wagner polarization technique which reveals that the percentage of ionic character of the salts are significantly higher compared with the polymer. The percentage of water uptake by the polymer and its salts were also observed.
Volume 42 | Issue 1