Effect of Heat Treatment on the Optical Properties of Plasma‐Polymerized Vinylene Carbonate Thin Films

Abstract

This paper describes the effect of heat treatment on the optical properties of plasma-polymerized vinylene carbonate (PPVC) thin films deposited on to glass substrates by low-pressure glow discharge plasma. Surface morphology and chemical structure of heat-treated PPVC were analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The surfaces of the PPVC thin films are observed to be smooth and pinhole free, and no significant change is observed due to heat treatment up to 573 K. The structural analyses of PPVC indicate that structural rearrangements may be due to the breaking of bonds, and this process enhances due to heat treatment. Ultraviolet-visible spectroscopic studies have been carried out on the as-grown and heat-treated PPVC thin films of different thicknesses. It is seen that the absorbance increases with the increase in the thickness and heat treatment temperature. The direct band gap energies were found to be in the range of 3.96-4.15 eV for as deposited, and those were in the range of 3.15-4.00 eV for the PPVC thin films heat treated at 473 and 573 K. The band gap of the PPVC thin film decreases gradually with increasing heat treatment temperature. C 2014 Wiley Periodicals, Inc. Adv Polym Technol 2015, 34, 21468; View this article online at wileyonlinelibrary.com.