Thermochromic behavior of unsymmetrical poly(alkylsilanes)

A description is given of the thermochromic behavior of a number of unsymmetrically substituted alkyl polysilanes. Of the polymers studied two groups are particularly interesting. The first group consists of polymers with n-alkyl side chains which are nearly the same length as the n-hexyl substituent. These materials have solution transition temperature and ranges which are essentially identical to that observed for poly(di-n-hexylsilane). The second group of polymers which are particularly interesting are those which have branched side chains. For these polymers (e.g. poly(di-4-methylpentylsilane) and poly(n-hexyl-4-methylpentylsilane)) the authors have observed that chain branching of the alkyl substituents dramatically alters the thermochromic behavior even when the branching sites are relatively remote from the silicon backbone.