Synthesis and physicochemical characterization of silica aerogels by rapid seed growth method
Synthesis and physicochemical characterization of silica aerogels by rapid seed growth method
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DOI：
10.1016/j.ceramint.2018.12.209
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发表时间：
2018
影响因子：
5.2
通讯作者：
Yue Zhang
中科院分区：
文献类型：
--
作者：
Tao Xia;Hailong Yang;Junning Li;Chencheng Sun;Chaoshuai Lei;Zijun Hu;Yue Zhang
Thankstothehighopticaltransparencyandultra-lowthermalconductivity,silicaaerogelsareidealmaterials for energy-saving windows. However, their preparation is commonly based on either one-step base-catalyzed method,ortwo-stepacid-basecatalyzedmethod,whichisdifficulttoinhibittheaggregationofclusterswhile keepingthesizeofclustersassmallaspossibleandthusdegradingsilicaaerogel'sproperties.Here,anewidea for synthesizing silica aerogels is presented from the viewpoint of controlling the growth and aggregation of silicaclusters.AcertainamountofTetramethoxysilane(TMOS)usedasseedprecursorisfirstlyaddedintothe mixtureofmethanolanddistilledwaterforhydrolysis.Acertaintimelater,theadditionalTMOSandadefined amount of ammonia are added to the obtained sol for promoting the rapid formation of the gel in several minutes. The silica aerogels prepared by this method have higher optical transparency and lower thermal conductivitythanthosepreparedbytheothertwomethods.Thisapproachmayalsoshedsubstantiallighton ontrollingthemicrostructureofothermaterialspreparedbysol-gelprocess.
