Vapor-phase synthesis of cross-linked ionic polymer thin films and its applications

Abstract

In this thesis, a new synthetic pathway to form cross-linked ionic polymers (CIPs) in vapor phase via initiated chemical vapor deposition (iCVD) is proposed. In spite of its huge research interest, ionic polymers could not have been synthesized in vapor phase, because the monomers for the synthesis of ionic polymers contain non-volatile ionic salts, preventing the monomers from vaporization. Moreover, most of ionic polymers are highly soluble in polar solvents due to the polar, ionic functionalities in the polymer chain. In order to improve the chemical stability of the ionic polymers, it is desirable to cross-link the ionic polymer without decreasing the amount of ionic functionalities in the polymer. However, it is not an easy task to form a uniform, conformal CIP thin film especially on non-flat, highly tortuous surfaces, because the cross-linking significantly limits the polymer chain mobility and thus, the processability of the polymer. In this research, the Menshutkin reactivity for cross-linking of polymers in vapor phase is investigated, and it is applied to oil/water separation membrane, silver nanowire (AgNWs) embedding matrix, and nano-adhesive depending on their reactivity.