Novel anion-exchange organic-inorganic hybrid membranes prepared through sol-gel reaction of multi-alkoxy precursors

A series of anion-exchange organic-inorganic hybrid membranes were prepared through sol-gel process from different precursors such as the copolymer of glycidylmethacrylate (GMA) and gamma-methacryloxypropy trimethoxy silane (gamma-MPS) (multi-silicon), N-triethoxysilylpropyl-N,N,N-trimethylammonium iodine (A-1100(+), mono-silicon) and monophenyltriethoxysilane (EPh) (mono-silicon). Influence of the copolymer's molecular weight on the sol-gel process and membrane formation is primarily investigated. It is demonstrated that copolymer with lower molecular weight (number average molecular weight, M-n, 8248) is more desirable to obtain homogenous and flexible hybrid membranes. Results also show that increasing the content of A-1100(+) could increase the membrane water uptake (W-R). ion exchange capacity (IEC) and membrane potential (E-m), while decrease in EPh content can result in an increase in W-R, E-m, and elongation at break (E-b). Generally speaking, the membranes have relatively strong hydrophobicity and high mechanical strength. The tensile strength (TS) can reach up to 88 MPa, and the E-b is in the range of 34-41%. Morphology studies show all the hybrid membranes are compact and homogenous even though they have high silica content (27.0-29.8%). (C) 2008 Elsevier B.V. All rights reserved.