Studies of chain conformational kinetics in poly(di-n-alkylsilanes) by spectroscopic methods. III. Fourier transform Raman studies of unsymmetric side chain substitution

Abstract

Fourier transform Raman (FT‐Raman) spectroscopy has been used to acquire spectra of polysilane derivatives in the absence of resonance effects arising from electronic absorptions of these materials between 320 and 370 nm. The nonresonant FT‐Raman spectra allow detailed analysis of the conformation of and lateral interactions between alkyl side groups. Comparison of spectra for the series of unsymmetrically substituted compounds poly(n‐pentyl,n‐hexylsilane), poly(n‐heptyl,n‐hexylsilane), and poly(n‐octyl,n‐hexylsilane) with the symmetrically substituted analog poly(di‐n‐hexylsilane) reveals various degrees of intra‐ and intermolecular disorder due to mismatch of side chain length. The induced disorder is well correlated with transition temperatures and UV‐vis absorption maxima.