A new method to prepare organic-inorganic hybrid membranes

In this paper we present a new method to prepare organic-inorganic hybrid PVDF/Si membranes by adding tetraethyl orthosilicate (TEOS) into the polyvinylidene fluoride (PVDF) casting solution. During the membrane coagulation in acid bath (pH = 1), the TEOS was hydrolyzed and polymerized, and silicon-oxygen polymers were formed. The silicon-oxygen polymers may entangle or interpenetrate with PVDF chains, which is beneficial to the mechanical performances of hybrid membranes. Element analysis showed Si existed on the surface and bottom of hybrid membrane when TEOS was added to the casting solution. The effects of TEOS on the performances of hybrid membranes were investigated. The results showed that the pure water flux increased firstly and then decreased and the BSA retention decreased with TEOS content increasing. When TEOS content was about 12 wt.%, the pure water flux of hybrid membrane was similar to that of PVDF membrane without TEOS addition, but the tensile strength and elastic modulus of hybrid membrane was almost twice.