Preparation of amphiphobically modified poly(vinyl alcohol) film by fluoroalkyl end-capped vinyltrimethoxysilane oligomer

Abstract

Hydrophilic poly(vinyl alcohol) (PVA) was chemically modified by using fluoroalkyl end-capped vinyltrimethoxysilane oligomer [RF-(VM)n-RF] to lead the PVA/RF-(VM)n-RF composite films. The PVA/RF-(VM)n-RF composite film obtained under non-catalytic conditions was found to provide the water-soluble property; however, the acidic conditions enabled the composite film to afford no solubility toward water, giving an amphiphobic property on both the surface and reverse sides just after the deposit of an oil or water droplet. RF-(VM)n-RF oligomer was also applied to the fabrication of the PVA/RF-(VM)n-RF/B(OH)3 composite film by using the RF-(VM)n-RF/B(OH)3 nanocomposites, which were prepared by the composite reaction of RF-(VM)n-RF oligomer with boric acid. It was demonstrated that the PVA/RF-(VM)n-RF/B(OH)3 composite film obtained by the interaction of the corresponding nanocomposites with PVA under acidic conditions can afford the perfect water-resistance ability even after immersion of this film into water for 30 min to give the amphiphobic property on both the surface and reverse sides, although the corresponding PVA/RF-(VM)n-RF composite film and the pristine PVA film provided the swelling behavior toward water, respectively. Thermal gravimetric analyses (TGA) and differential thermal analyses (DTA) measurements showed that the PVA/RF-(VM)n-RF/B(OH)3 composite film can give a higher thermal stability than that of the RF-(VM)n-RF/PVA composite film and the pristine PVA film.