原子力显微镜在纤维素研究中的应用

Application of Atomic Force Microscope in Cellulosic Ivestigation

原子力显微镜(AFM)作为一种重要的表面成像技术,可在不同工作模式(接触式、非接触式和敲击式等)下通过对探针与样品表面作用力的监测表征纤维素及其衍生物的大分子结构特征和纤维素材料的表面形态特征。通过AFM观测发现:在结构上天然纤维素以纤维二糖为重复单元,结晶区内单斜晶系和三斜晶系紧密相关并以1/4重复单元的错位排列;在细胞壁中,微纤丝之间通过半纤维素相连形成网状结构,且分子微细结构随植物种类、细胞壁区域的不同而变化。在纤维素的应用研究中,AFM对纤维素基材料的研究起到了有效的推动作用,为纸浆性能的提高、纸张保存、材料制备中反应历程和机理的探索提供了理论依据。

Atomic force microscope （AFM） plays an important role in the surface imaging technologies. The basic principle of AFM is the measurement of the force between a sharp tip and sample surface. In order to profile the structure characteristics of biopolymers, AFM can work under contact mode, non-contact mode and tapping mode, respectively. High-resolution images of cellulose from AFM show that cellobiose is the repeat unit of cellulose, and triclinic and monoclinic crystal systems naturally exist in the same microfibril of cellulose with a displacement of adjacent chains by a quarter of cellobiose units. In cell wall, fibers contact with each other by hemicelluloses to form a network. However, the structure of fiber ranges with variety of plants and cell wall region. Furthermore, AFM promotes the application research on cellulose. The results from AFM images are important for improving of pulp properties, paper conservation, and exploration of reaction mechanism.