Sol–gel technology for functional finishing of PES fabric by stimuli-responsive microgel

The possibility of incorporating a stimuli-responsive microgel into a silica matrix by the sol–gel method was studied. This method allows the preparation of a novel class of functional finishes for textile material modification, which is aimed at the creation of simultaneous stimulus-responsive behaviour and functional protective properties. Using a pad-dry-cure method, a thermo- and pH-responsive microgel (PNCS) based on poly-(N-isopropylacrylamide) (poly-NiPAAm) and chitosan was embedded into a silica matrix on a previously activated polyester (PES) fabric. The matrix was composed of a model sol–gel precursor, vinyltrimethoxysilane (VTMS), in combination with hydrophilic fumed silica nanoparticles (SiO2). Functionalized PES fabric samples were characterised by determining the morphological and chemical properties using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The stimuli (temperature and pH) responsiveness of the functionalized PES fabric was established by measuring its porosity, wicking ability, moisture content, drying rate, water vapour transmission rate and water uptake. In order to assess the washing fastness of the surface modifying systems, the tests were done before and after five consecutive washings. The results showed that sol–gel technology is an appropriate method for the incorporation of PNCS microgel on PES fibre surface. Because of the elasticity of the sol–gel matrix, the VTMS/SiO2 polysiloxane film had no adverse influence on the swelling/deswelling effect of the PNCS microgel, thus retaining and even enhancing its stimulus response.