Hydrophilic hybrid SiO2:polyethylene glycol–3-isocyanato-propyltrietoxysilane nanocomposite films

SiO2:polyethylene glycol (PEG)–3-isocyanato-propyltrietoxysilane (IPTES) hydrophilic films were prepared from PEG having various average molecular weights, namely 200, 400 and 600; SiO2 nanoparticles, and tetraethyl orthosilicate (TEOS) through sol–gel method. SiO2 nanoparticles were utilized in various amounts to enhance the mechanical properties and hydrophilic character of the films. Films were characterized by Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, atomic force microscopy, adhesion test, humidity test and water contact angle (WCA) measurements. Thicknesses of the obtained films were about 800nm. Incorporation of TEOS enhanced adhesion of film to substrate as well as improving stability of the film against water. WCA was seen to decrease, and porosity and surface roughness was seen to increase with increase in SiO2 nanoparticle content of the films. Increase in PEG molecular weight also resulted in a decrease in the WCA, thus WCA as low as 15° was obtained. ► SiO2:polyethylene glycol (PEG)–3-isocyanato-propyltrietoxysilane (IPTES) films formed. ► PEG molecular weight (MW) and SiO2 particles content influence the hydrophilicity. ► Increased PEG MW and SiO2 content in the films decrease the water contact angle (WCA). ► Addition of tetraethoxysilane in the films resulted in well-adhered films. ► WCA of the SiO2:PEG–IPTES films increased following 6-week humidity tests.