Neutron diffraction study of the pore surface layer of VYCOR glass.
Neutron diffraction study of the pore surface layer of VYCOR glass.
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VYCOR 玻璃孔表面层的中子衍射研究。
DOI：
10.1103/physreve.55.3021
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
J. Axe
中科院分区：
文献类型：
--
作者：
M. Agamalian;J. Drake;S. Sinha;J. Axe
结合宏观测量的小角散射和粉末衍射数据的分析揭示了在Vycor玻璃，由OH基团和化学吸附水的孔隙表面层的结构。化学吸附水以两种形式存在于孔隙表面：由{approximately}40{endash}60个分子组成的紧密水簇，通过氢键相互连接，以及更空间分布的单个分子（或多个分子的组）。加热至650 ℃重建孔表面：由于Si-OH和B-OH表面基团之间的脱水反应，OH基团的数量显著减少。然而，温度处理并不影响水分子团簇的形成过程，水分子团簇在缩合后仍然出现在孔表面。{版权} {美国物理学会}
Analysis of small-angle scattering and powder diffraction data combined with macroscopic measurements have revealed the structure of a pore surface layer in Vycor glass, consisting of OH groups and chemisorbed water. Chemisorbed water exists on the pore surface in two forms: compact water clusters of {approximately}40{endash}60 molecules, connected to each other by hydrogen bonds, and more spaciously distributed individual molecules (or groups of several molecules). Heating to 650{degree}C reconstructs the pore surface: the number of OH groups is significantly decreasing due to the reaction of dehydration between Si-OH and B-OH surface groups. However, the temperature treatment does not affect the process of H{sub 2}O clusters formation, which still appear on the pore surface after the condensation. {copyright} {ital 1997} {ital The American Physical Society}