具有不同长度间隔基的含联苯基团的侧链液晶聚炔的荧光行为(英文)

Fluorescence Behavior of Biphenyl Containing Side-Chain Liquid Crystalline Polyacetylene with Various Lengths of Spacers

对一系列具有不同长度间隔基的含联苯基团的侧链液晶聚炔的稳态荧光和荧光衰减行为进行了研究.为便于比较,选取其中一个单体作为模型化合物.稳态荧光光谱结果表明,聚合物和单体均显示一个荧光发射,该荧光发射来源于聚合物侧链的联苯基团.随着间隔基长度的减小,聚合物的荧光强度降低.荧光衰减结果表明单体的荧光衰减可以拟合为一个单指数衰减,而聚合物的荧光衰减拟合为三指数衰减.这种三指数衰减可能由溶液局部高浓度引起的猝灭和侧链联苯基团的旋转受阻所引起.溶剂效应表明,溶剂与联苯基团之间的相互作用随溶剂极性增加而增大.

Steady state fluorescence and fluorescence decay of a series of monosubstituted biphenyl containing sidechain liquid crystalline polyacetylenes with different lengths of spacers were investigated. For comparison, a monomer was selected as a model compound. Steady state fluorescence spectra elucidated that the polymers and the monomer showed single fluorescence emission arising from the biphenyl group on the side chain. With decreasing the length of the spacer, the fluorescence intensity of the polymer decreased accordingly. The fluorescence decay showed that the decay of the monomer could be fitted to be a single-exponential decay, while that of the polymers should be fitted to be a triple-exponential decay, which may be originated from the local high concentration induced quenching and the rotational restriction of the side-chain biphenyl groups. Solvent effects illustrated that the interaction between the solvents and the biphenyl groups strengthened with increasing the polarity of the solvents.