反应型凝胶剂2,4-二烷脲基甲苯衍生物及有机溶剂的室温凝胶化研究

Reaction-type Gelators of 2,4-Bis(N'-alkylureido)toluene Derivatives and the Organogel Formation at Room Temperature

通常制备有机分子凝胶是在高温下溶解凝胶剂,凝胶剂分子在冷却过程中进行自组装并使有机溶剂凝胶化.该方法限制了某些低沸点溶剂的凝胶化.利用甲苯二异氰酸酯与烷基胺的高反应活性,制备了3种反应型凝胶剂.这种反应型凝胶剂能以较低的浓度在室温下使某些芳香族和卤代烃溶剂形成热可逆的有机分子凝胶.场发射扫描电镜表明这种反应型凝胶剂在有机溶剂中自组装形成纤维状三维网络结构.随着烷基胺中的烷基链长度不同,形成的纤维状聚集体的形态也不同.FT-IR和1HNMR研究表明分子间氢键作用是反应型凝胶剂自组装的驱动力.通过XRD和分子模拟推测了其聚集体的结构形态.

Three kinds of reactable gelators with different alkyl chains were synthesized by using the high activity of isocyanate and alkylamine, and molecular gels could be obtained at room temperature. The gels were formed from 2,4-bis（N＇-alkylureido）toluene （BAUT-n, n is the number of carbon atoms in the alkyl） that can aggregate and self-assembly, forming thermal reversible gels with several organic solvents at very low concentrations. The self-assembly properties of such gelators in organic solvents were investigated. FE-SEM revealed a three-dimensional （3D） network consisting of fiber-like aggregates, which inhibited the fluidity of organic solvents, thus forming gels. Moreover, various lengths of alkyls led to different morphology of fiber-like aggregates. FT-IR and 1H NMR demonstrated that intermolecular hydrogen bonding was main driving force for the self-assembly and formation of the gels. Finally, a self-assembly mode was proposed through the results of XRD and molecular stimulation.