The studies of molecular structure of Poly(1-trimethylsilyl-1-propyne) stereoisomers by the flow birefringence method

Abstract

Optical properties of poly-1-trimethylsilyl-1-propyne (PTMSP) stereoisomers in solutions have been studied by means of flow birefringence method. Stereoisomers were chosen with various trans- and cis-configurations abundances of double C C bonds in monomeric units. The differences of main polarizabilities ( α 1 − α 2) or statistical segments have been determined. Significant growth of ( α 1 − α 2) values with increasing of the trans-isomer contents in chain molecule has been found. Optical anisotropy of monomeric segments, having cis- and trans-configurations, has been theoretically evaluated. It has been shown that observed significant increase of experimentally measured ( α 1 − α 2) values cannot be sufficiently explained by only specific chain polarizability growth due to higher trans-isomers contents. It has been demonstrated that high ( α 1 − α 2) value and it’s growth with increase of abundance of monomeric segments in trans-configuration has been caused by thermodynamical rigidity increase, i.e., higher number of monomeric units included into PTMSP statistical segment.