水分子凝胶中有机凝胶因子聚集体的分形结构研究

Fractal structure of water molecular gels formed by the aggregation of organogelators

水分子凝胶是一种新型软凝聚体系 .是凝胶因子在很低的浓度下在水中聚集、自组装 ,使水凝胶化形成的凝聚体系 .透射电镜 (TEM)表明凝胶因子在水中聚集、自组装成细纤维状结构 .通过对TEM照片进行数字化处理 ,采用Sandbox法和密度 密度相关函数法计算的结果表明凝胶因子在聚集组装过程中具有典型的分形特征 .根据C ++程序计算出分形维数D =1 814— 1 977.以分形理论对凝胶因子的聚集过程以及由此形成的水分子凝聚体系的分形特征进行了讨论 .利用小角x射线散射 (SAXS)研究进一步表明 ,凝聚体系的分形结构存在于尺度α =1nm与ε=4 0nm之间 ,且在较大的范围内具有分形特征 ,分形维数D =1 9.两种方法的研究结果是一致的 .

Water molecular gel is a kind of soft condensed systems. It was formed by the aggregation and self-assembly of gelator 4,4′-bisstearylamide diphenyl ether (BSADE) which makes water into gelation at very low concentration in water. Its microcosmic morphology, thin fibre-like aggregate, was observed by transmission electron microscope(TEM) of the gels. By digitalized treatment of TEM photos, the structure of three-dimensional networks of gels shows a typical fractal characteristic. The fractal dimension D of the gels was calculated by the methods of Sandbox and density-density correlation function under the C++ program. The fractal dimension D calculated by the two methods is in the range of 1 814—1 977. Through the fractal theory, the aggregation process of gelator and the fractal characteristic of the gels was discussed. Further investigation by small angle x-ray scattering indicated that the fractal scale of the gels is between α =1nm and ε =40nm. and fractal characteristic was shown in a larger area. Its fractal dimension is 1 9, which is in agreement with the results from TEM method.