具多重氢键寡聚芳酰胺的合成及自组装

Synthesis and Self-Assembly of an Oligoaramide Containing Multiple Hydrogen Bonds

含六重氢键寡聚芳酰胺双分子链在没有相应互补链的情况下,其中一条链发生自组装.通过紫外-可见(UV-Vis)光谱、动态光散射(DLS)、扫描电镜(SEM)和透射电镜(TEM)等实验手段,对其自组装行为进行了研究.实验结果表明,在1,2-二氯乙烷中随温度升高在紫外区吸收发生蓝移,说明酰胺自组装体部分解聚.该分子链在不同极性的溶剂中都能发生自组装,并随极性不同表现为不同的形貌.如在甲苯中呈网状结构,在极性相对较弱的二氯甲烷和环己烷的混合溶剂中为不规则的蜂窝状结构,而在三氯甲烷和甲醇组成的极性混合溶剂中则组装成稳定的实心微球,其直径随着浓度升高而增大,通过在乙腈中的降温过程,观察到组装体形貌由管状纤维向实心球的转变.

An oligoaramide duplex containing multiple hydrogen bonds was found to undergo self-assembly in the absence of its corresponding complementary strand. The self-assembly behavior of the molecular oligoaramide was examined using multiple techniques including ultraviolet-visible （UV-Vis） spectrum, dynamic light scattering （DLS）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The result from the UV-Vis experiment indicated a hypsochromic shift within the ultraviolet region in 1,2-dichloroethane with increasing temperature, suggesting partial disintegration of supramolecular aggregates. The oligoaramide was found to self-assemble in solvents of different polarity presenting different types of morphologies. For example, reticulation-like morphology was observed when using toluene as a solvent; an irregular honeycomb appeared in the mixed, relatively less polar dichloromethane and cyclohexane. In addition, stable solid balls formed instead of vesicles upon self-assembling in a mixed polar solvent of chloroform and methanol. The diameters of these spherical aggregates increased with concentration. Furthermore, the transformation of assemblies from tubular fibers in hot acetonitrile to solid spherical aggregates was observed upon cooling.