Effects of solvent in the casting of poly(1-trimethylsilyl-1-propyne) membranes

Poly(1-trimethylsilyl-1-propyne) (PTMSP) membranes were fabricated by solve nt casting from solutions of toluene, cyclohexane and tetrahydrofuran. The effects of the casting solvent on the physical structure of PTMSP were inve stigated using wide angle X-ray diffraction and positron annihilation lifet ime spectroscopy. The permeability of oxygen, nitrogen and carbon dioxide t hrough the cast membranes was also measured. It was found that the nature o f the casting solvent markedly influenced the conformation and the free Vol ume of PTMSP, which in turn affected the gas permeability of the cast membr anes. (C) 2000 Elsevier Science Ltd. All rights reserved.