Columnar mesophase behaviour of poly(di-n-butylsiloxane) and related copolymers containing polar substituents

The columnar mesophase formation of poly(dibutylsiloxane) (PDBS) was studied with respect to the influence of molecular weight. Additionally, the synthesis of random copolymers containing dibutylsiloxane and butyl(3-cyanopropyl)siloxane units was performed in order to examine the influence of side group polarity on the columnar mesophase behaviour without disturbing the overall molecular geometry. Introduction of 6% 3-cyanopropyl groups appeared to hinder crystallization while copolymers containing 17% 3-cyanopropyl groups did not show crystallization at all. All copolymers formed a columnar mesophase which seemed to gain stability from the presence of the polar substituents