Determination of surface energies and acidity-basicity numbers of protonated and deprotonated forms of poly(sulfonic acid diphenyl aniline) by inverse gas chromatography

Abstract

Protonated form of poly(sulfonic acid diphenyl aniline) (p-PSDA) was synthesized through oxidative chemical polymerization of sodium salt of diphenylamino-4-sulfonic acid in hydrochloric acid and then, its deprotonated form (PSDA) was obtained by neutralization with aqueous ammonium hydroxide solution. The samples were characterized by thermal analysis and Fourier Transform Infrared, Ultraviolet-visible, H-1-NMR spectroscopy techniques. Their dispersive surface energies as well as surface acidity and basicity were determined by inverse gas chromatography at temperatures between 313 and 353 K. The dispersive surface energy of p-PSDA was found to be considerably lower but it increased with temperature while that of PSDA was close to those of conventional polymers and decreased slightly with temperature. According to the Schreiber's procedure, the surfaces of p-PSDA and PSDA were found to be acidic and amphoteric, respectively. It was observed from the electron microscope images p-PSDA chains can form self-organized circular polydisperse micro-sized aggregates in aqueous solutions while PSDA cannot self-organize to form individual aggregates. POLYM. ENG. SCI., 55:1246-1254, 2015. (c) 2015 Society of Plastics Engineers