基于二维SEM图像的介孔碳表面分形特征分析

Study on Surface Fractal Character of Mesoporous Carbon Based on Two-dimensional SEM Image

将分形理论引入到介孔碳孔结构表征,基于SEM图像计算二维分形维数(D2)及三维分形维数(D3),并分析了分形维数与孔结构参数之间的规律。结果表明,D2及D3能有效地量化介孔碳形貌的差异,两者随形貌的变化一致,即D2越大D3也越大。当介孔碳的显气孔率相近时,平均孔径越小D2和D3越大,反映出介孔碳具有越多的细部特征和越粗糙的表面。

Mesoporous carbon was prepared from mixture ot phenol resin, the pore microstructures were cnaracterized by mercury porosimetry and FESEM. Based on FESEM image, the surface fractal dimensions, D2 and D3 were estimated by using box-counting method and Sarkar-Chaudhuri method, respectively,which denoted two-dimen sional（2D） and three-dimensional（3D） characteristics of surface morphology of mcsoporous carbons. The result shows that the average pore sizes of mesoporous carbons are controlled between 22.9nm and 39. 9nm. Surface fractal dimensions of D2 can give a quantitative evaluation of surface irregularity of mesoporous carbons while surface fractal dimensions of D3 can give a quantitative evaluation of surface coarseness of mesoporous carbons. Consistent relationship he tween D2 and D3 is revealed when they denote characteristics of surface morphology of mesoporous carbons. The mesoporous carbons with less average pore size have bigger fractal dimension, which is the origin of geometrical irregularity and coarseness.