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Title : 大连理工大学（土木水力学院） 建筑材料研究所 所长 大连理工大学建筑能源技术研究中心 主任 辽宁省复合材料学会常务副理事长兼秘书长 政协辽宁省委员会委员 “建筑技术与应用”“混凝土”和“国外连建材科技“等杂志编委
Title of Paper:Influence of drying methods on fractal geometric characteristics of mesoporous silica aerogels
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Date of Publication:2013-06-01
Journal:JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
Included Journals:SCIE、EI、ISTIC
Volume:28
Issue:3
Page Number:476-482
ISSN No.:1000-2413
Key Words:silica aerogel; N-2 gas adsorption; surface fractal dimension; mesoporous structure
Abstract:Chemical modification/ambient drying method and freeze drying method were introduced to research the synthesis of mesoporous silica aerogels. By analyzing N-2 gas adsorption/desorption isotherms, the fractal geometric characteristics of gels were focused. The overall surface fractal dimensions were determined by analyzing N-2 gas adsorption branch and a Frenkel-Halsey-Hill (FHH) equation was empolyed to determine surface fractal dimension D (f). It is found that, during ambient drying process, V (TMCS)/V (Wetgel) ratio plays a crucial role in the changes of geometric feature, the key point is 50%, when the ratio is lower, and surface roughness increases with the ratio, when it exceeds 50%, the surface is almost unaffected by the modification. While freeze drying always tends to get larger D (f), freeze drying process could cause a rough surface of the gels. Compared with traditional porosity and specific surface area analyses, fractal geometry may be expected to be favorable for mesoporous structural analyses of materials.
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