取代聚苯胺的聚集态结构

Studies on the Structure of the Aggregated State of Ring-substituted Polyaniline

环取代基及掺杂对聚苯胺分子链结构产生影响的同时也对大分子聚集态结构产生影响.通过对聚合物膜的XRD、SEM研究,表明在所合成的环取代聚苯胺衍生物中,聚合物的结晶性依POT(聚邻甲苯胺)、PDMAn(聚-2,5-二甲氧基苯胺)、PmClAn(聚间氯苯胺)顺序增加;与本征态的比较,质子酸掺杂后聚合物的结晶性有所提高.POT基本上表现出了非晶聚合物的性质;PDMAn具有同质多晶的结构特征,但结晶度较低;PmClAn表现出了典型高分子晶体性质,符合单斜晶系的特征(晶胞参数为a=0.679nm,b=2.304nm,c=0.5734nm,α=90°,β=100.9°,γ=90°).采用HyperChem程序包中的MM+分子力学方法对1H-NMR和XRD实验结果进行结构优化,确定了苯式结构/醌式结构为3/2的PmClAn大分子链的构象.

Ring-substituted groups and doping not only have a great effect on the chain structure of polyanilines, but also on their aggregated state due to its electronic and steric effect. When steric hindrance increases, the crystallinity declines. Within the same molecular chain or between different molecular chains, the forming of hydrogen bond contributes to increasing crystallinity. From SEM and XRD experiments of polymer films it was found that the crystallinity of the ring-substituted polyanilines synthesized increases in the order of poly-o-toluidide (POT), poly-2, 5-dimethoxyaniline (PDMAn) and poly-m-chloroaniline (PmClAn). In comparison to their corresponding undoping polymers, it was concluded that proton doping of polyanilines renders their crystallinity increased. POT basically showed amorphous, while PDMAn allomorphous with low crystallinity. On the other hand, PmClAn is characterized by its molecular crystalline, being monoclinic with crystall-cell parameters of a = 0.679 nm, b = 2.304 nm, c = 0.5734 nm, alpha = 90degrees, beta = 100.9degrees, and gamma = 90degrees. By using MM+ molecular mechanics methode in HyperChem program, (HNMR)-H-1 and X-ray diffraction data were analyzed, thereby the configuration of PmClAn chain was determined and optimized, the results show that in the macromolecular chain of PmClAn the ratio of benzoid to quinoid units is 3:2..