XPS studies on surface modified poly[1-(trimethylsilyl)-1-propyne] membranes. II Surface modification by bromine vapor

Surface modificition of poly [1-(trimethylsilyl)-1-propyne] (PTMSP) membranes by bromine vapor has been studied It is shown that Br/C atomic ratio at the surfaces increased with the time of bromination until about 60 min; then it reached a plateau. The results of XPS and IR studies indicated that the addition of bromine to double bonds and the replacement of H on CH₃ by bromine had taken place so that a new peak at 286. 0 eV (C - Br) in C_1s spectra and some new bands, e. g. at 1220 and 580cm^-1, in IR spectra were formed. The fact, PO₂, permeability of oxygen, decreased and α_O(2)/_N(2), separation factor of oxygen relative to nitrogen, increased with bromination time, shows that surface modification of PTMSP by bromine may be an efficient approach to prepare PTMSP membranes used for practical gas separations.