Preparation of telechelic polysilylenes: A general methodology for the synthesis of polysilylene-based triblock copolymers

Telechelic polysilylenes have been developed involving the chemical degrada tion of poly(di-n-hexylsilylene) with bromine. The molecular weight of the newly formed telechelic PDHS depends on the ratio of bromine to the startin g PDHS. The percentage of end groups increases as the molecular weight of t he telechelic PDHS is lowered, reaching a maximum of 99% difunctionality. P olystyrene-PDHS-polystyrene triblock copolymers have been prepared by coupl ing polystyryllithium to the telechelic PDHS in the presence of cryptand [2 .1.1]. The effect of molecular weight on the disordering transition of PDHS into a columnar mesophase has been studied, and temperature and enthalpy h ave been shown to decrease by the presence of the PS end groups and eventua lly became unobservable at high fractions of PS. The morphologies of the tr iblock copolymers were studied by atomic force microscopy.