Determination of pore fractal dimensions and porosity of silica glasses from the dielectric response at percolation
Determination of pore fractal dimensions and porosity of silica glasses from the dielectric response at percolation
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DOI：
10.1103/physrevb.60.14348
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发表时间：
1999-11
影响因子：
3.7
通讯作者：
A. Puzenko;Nick Kozlovich;A. Gutina;Y. Feldman
中科院分区：
文献类型：
--
作者：
A. Puzenko;Nick Kozlovich;A. Gutina;Y. Feldman
渗流介电弛豫谱分析用于测定二氧化硅玻璃的孔隙分形维数和孔隙率。多孔玻璃中的渗流现象与由于质子和离子沿着连通孔的孔表面迁移而在发达的开放孔网络内的电激发转移有关。介电谱技术使我们能够识别与渗流相关的弛豫过程，并提取与多孔介质内电荷载流子迁移相关的激发转移路径的分形维数。随机分形模型描述了多孔基体的几何无序性。在该模型的框架下，得到了多孔空间分形维数与介质孔隙率之间的关系。结构模型和松弛模型的并置使我们能够推导出孔隙率值与多孔介质内激发传递路径的分形维数之间的关系。介绍了通过开发的理论方法和介电谱测量获得的几种多孔二氧化硅玻璃的实验孔隙率值。发现从介电谱方法获得的孔隙率值与从相对质量减少的测量获得的数据非常一致。 @S0163-1829~99!11743-0#
The analysis of the dielectric relaxation spectrum at percolation was used for the determination of the dimensions of pore fractals and porosity of silica glasses. The percolation phenomenon in the porous glasses is related to the transfer of the electric excitation within the developed network of open pores due to migration of protons and ions along the pore surface of connected pores. The dielectric spectroscopy technique allows us to identify the relaxation process related to percolation, and to extract the fractal dimensions of the paths of excitation transfer associated with migration of charge carriers within the porous medium. The random fractal model describes the geometrical disorder of the porous matrix. In the framework of this model, the relationship between the porous space fractal dimension and the porosity of the medium has been obtained. The juxtaposition of the structural and the relaxation models enables us to derive the relationship between the value of porosity and the fractal dimensions of the paths of excitation transfer within the porous medium. The experimental porosity values for several porous silica glasses obtained by means of the developed theoretical approach and dielectric spectroscopy measurements are presented. The porosity values obtained from the dielectric spectroscopy method are found to be in good agreement with the data obtained from the measurements of the relative mass decrements. @S0163-1829~99!11743-0#