二维凝胶体系中碳酸钙分形结构的形成与机理研究

Preparation and Formation Mechanisms of Calcium Carbonate Fractal Aggregates in Agar Gel

本文研究了二维琼脂凝胶圆盘体系中碳酸钙分形结构的形成过程,发现随着反应时间的增加,碳酸钙的形态经过了细小颗粒-枝晶结构-分形结构的转变过程,该分形结构实际上是由纳微米级碳酸钙晶粒聚集而成的。增加琼脂和反应物的浓度,碳酸钙微晶的形貌和尺寸发生了变化,呈现立方体与球形,由其构成的分形结构的尺寸也随着改变,但碳酸钙的晶型均为方解石型,无明显变化。二维凝胶体系中碳酸钙分形结构的形成主要与琼脂极性基团提供成核位点、多糖的网络结构、沉淀剂离子扩散受限有关。

Fractal growth of calcium carbonate was found in 2D agar gels. Remarkable morphological evolution of calcite from crystalline to ramified aggregates to tree-like fractal aggregates as induction time increased has been observed. Marked morphological and dimension changes of crystals were observed to be dependent on the concentration of agar and precipitator. Although,the sizes of tree-like fractal aggregates consisting of global blocks and cubical crystals also changed,all the crystals were identified to be orthorhombic CaCO3 crystals. The experimental results reveal that fractal growth could occur successfully in agar gels,which was influenced by the polar groups of agar,network-like structure of amylase and pervasion of precipitators,and so on.