Estimation of free volume in poly(trimethylsilyl propyne) by positron annihilation and electrochromism methods

Lifetime analysis of positron annihilation spectra of poly(trimethylsilyl) propyne) (PTMSP) revealed an additional long-lived component that is not typical for most of previously studied polymers. A model that has been developed earlier predicts that this lifetime corresponds to the larger size of free-volume elements having an intrinsic radius of about 6 A. Therefore, PTMSP should be similar to porous inorganic sorbents. A comparison with the literature for zeolites and silica gel confirms this. According to the eelectrochromism method, the temperature dependence of the sisze of free-volume elements for PTMSP is much weaker than that for regular glassy polymers like polystyrene