AFM对壳聚糖富集银离子的分形学研究

利用原子力显微镜(AFM)对壳聚糖吸附银离子进行研究，从形貌学的角度探测壳聚糖络合银离子的机理特性．主要方法是将溶液滴加在新解离的云母片上，应用原子力显微镜对自然风干后的样品在非接触模式下成像．AFM图像显示：壳聚糖分子和加过金属银离子的壳聚糖分子在聚集生长过程呈现为传统的具有分形特征的正态分布和奇异分布；由单一的壳聚糖分子形成的分形结构为“星”形结构，而加过银离子的壳聚糖分子形成的结构为“圆”形．产生这些图形差别的根本原因是由于生长界面的表面张力及其各向异性起了重要作用．这两种结构都具有典型的自相似性，且实验结果与计算机模拟的分形模式拟合得很好．

AFM Study of the Fractal Structures of Chitosan after Enriching Ag+

The mechanism of the process that Ag~+ was absorbed by chitosan was studied in this paper based on AFM images. Prepared solution was deposited onto new freshly cleaved sheets of mica, dried in air and scanned by noncontact mode AFM. AFM images show that chitosan aggregates and those absorbs Ag~+ with fractal characteristics of traditional normal distribution and singular distribution. Chitosan aggregates in star-like structure, while those which absorb Ag~+ grow disc-like structure. These significant differences may be explained by the surface tension of the interface and the anisotropic characteristic. Both structures demonstrate good self-similarities and are well consistent with the fractal model simulated by computer.