基于偏苯三甲酸与对羟基吡啶复合物的超分子水凝胶

基于偏苯三甲酸和对羟基吡啶合成了一种具有支化结构的凝胶因子,采用氢核磁、红外光谱及元素分析确认其结构.该凝胶因子熔体在冷却时可拉出数厘米的长丝,表明分子间形成了强相互作用.将凝胶因子的水溶液分别在25℃和0℃下自然冷却、以及在25℃的超声作用下冷却,凝胶因子自组装成纤维状网络结构并使水凝胶化,纤维网络的密度及凝胶的稳定性均按上述凝胶形成条件顺序增加.通过干凝胶能谱面扫描分析发现氮元素主要处于纤维内部,表明两亲性凝胶因子对分子自组装的影响.通过分析邻苯二甲酸与对羟基吡啶复合物、偏苯三甲酸的单晶结构表明,凝胶因子基于多种氢键识别作用组装成纤维结构.干凝胶的粉末X射线衍射分析表明在凝胶化过程中凝胶因子沿着特定方向进行组装.

SUPRAMOLECULAR HYDROGELS BASED ON 1,2,4-BENZENETRICARBOXYLIC ACID AND 4-HYDROXY PYRIDINE

A branched gelator synthesized from 1,2,4-benzene tricarboxylic acid and 4-hydroxy pyridine was characterized by 1H-NMR,IR and elemental analysis. Supramolecular fiber with length of several centimeters was formed by pulling up the melting sample of the gelator,indicating a strong interaction of the molecules. Three supramolecular hydrogels were obtained via cooling the gelator aqueous solutions at 25℃ ,0℃ and at 25℃ under ultrasonic treatment,respectively. The results indicated that the gelator molecules assembled into fibrillar networks during forming the gels with the network density and gel stability increased by the order of the above formation methods. The electron spectroscopic spectrum of the xerogel surface reveals that the nitrogen atom locates mainly within the fiber,indicating the molecular assembling in water is affected by the amphiphilic gelator molecule. The assembling fashion of the gelator was further investigated by analyzing the single crystal structures of the complex formed from 4-hydroxypyridine and o-phthalic acid,and 1,2,4-benzene tricarboxylic acid,which shows that the molecules assembled into branched fiber via different hydrogen bonding. Moreover, the powder X-ray diffraction diagram of the xerogel indicates that the gelator molecules assembled in a preferred direction during forming the gel.