Thermally stable oxadiazole-containing polyacetylenes: Relationship between molecular structure and nonlinear optical properties
作者:Xin Wang、Shanyi Guang、Hongyao Xu、Xinyan Su、Junyi Yang、Yinglin Song、Naibo Lin、Xiangyang Liu
DOI:10.1039/b807004k
日期:——
Two novel high molecular weight functional polyacetylenes bearing oxadiazole groups as pendants, poly(2-(4-decyloxyphenyl)-5-(4-ethynylphenyl)-1, 3, 4-oxadiazole) (P1) and poly(2-(4-butyloxyphenyl)-5-(4-ethynylphenyl)-1, 3, 4-oxadiazole) (P2) were designed and synthesized by a multistep reaction route. The structures and properties were characterized and evaluated with FTIR, NMR, UV, TGA, GPC, optical-limiting (OL) and nonlinear optical (NLO) analyses. The incorporation of oxadiazole into polyacetylene significantly endows polyacetylenes with higher thermal stability and optical limiting property. The solubility, stereoregularity and optical properties of resultant polyacetylenes are obviously affected by flexible terminal alkoxy chain length. The cis olefinic structure content in polyacetylene backbone increases with increasing terminal alkoxy group length. The functional polyacetylene with the higher cis olefinic structure content shows higher thermal stability, better optical limiting property and larger third-order nonlinear optical performance. The optical limiting mechanism of resulting polymers was investigated, which is mainly originated from larger excitation state absorption cross-section of molecules to result in reverse saturable absorption.
两种带有恶二唑基团作为侧链的新型高分子量官能化聚乙炔,聚(2-(4-癸氧基苯基)-5-(4-乙炔基苯基)-1,3,4-恶二唑)(P1)和聚(2-(4-通过多步反应路线设计并合成了丁氧基苯基)-5-(4-乙炔基苯基)-1,3,4-恶二唑)(P2)。通过 FTIR、NMR、UV、TGA、GPC、光学限制 (OL) 和非线性光学 (NLO) 分析对结构和性能进行了表征和评估。将恶二唑引入聚乙炔中显着赋予聚乙炔更高的热稳定性和光限幅性能。柔性末端烷氧基链长度明显影响所得聚乙炔的溶解度、立构规整性和光学性质。聚乙炔主链中的顺式烯属结构含量随着端烷氧基长度的增加而增加。顺烯结构含量较高的功能聚乙炔表现出较高的热稳定性、较好的光限幅性能和较大的三阶非线性光学性能。研究了所得聚合物的光限幅机制,其主要源于分子较大的激发态吸收截面,导致反向饱和吸收。