Fabrication of pH Responsive Thin Film Using a One-Step Environmentally Friendly Plasma Enhanced Chemical Vapor Deposition

Abstract

Abstract In recent years, there has been growing interest in pH responsive polymers. Polymers with ionizable tertiary amine groups, which have the potential to be used in many critical application areas due to their pKa values, have an important place in pH responsive polymers. In this study, poly(2-Diisopropyl aminoethyl methacrylate) (PDPAEMA) thin films were coated on various substrates such as glass, fabric and silicon substrate using a one-step environmentally friendly plasma enhanced chemical vapor deposition (PECVD) method. The effects of typical PECVD plasma processing parameters such as substrate temperature, plasma power, reactor pressure on the deposition rate were studied. The highest deposition rate was obtained at a substrate temperature of 40 °C, a reactor pressure of 300 mtorr, and a plasma power of 60 W. The apparent activation energy was found to be 17.56 kJ/mol. Based on the results of this study, uniform film thickness and surface roughness were observed at large area. The PDPAEMA thin film was exposed to successive acid/base cycles. The results showed that the pH sensitivity of the thin film produced by the PECVD method is permanent and reversible.