Poly(di-n-pentylsilylene) copolymers containing diethyleneglycol-diethylether side chains

Poly(dipentylsilylene) copolymers containing 4,7,10-trioxadodecylmethylsilylene units as comonomer were synthesized via a Wurtz-type coupling reaction from the corresponding dichlorosilanes. The copolymers were characterized by GPC and NMR spectroscopy. Solvent- and temperature-dependent UV absorption was observed. The bulk polymers underwent broad endothermic transitions below room temperature, whose temperature and heat effect depended on the incorporation of comonomer. This suggested that the high-temperature state can be described as a columnar mesophase corresponding to the well established case of the poly(dipentylsilylene). Correlated to this transition, the copolymers also showed thermochromic behavior at low temperatures. The materials could be oriented by shearing in the mesophase, which was demonstrated by polarized optical microscopy, polarized IR spectroscopy and UV spectroscopy.