Molecular mechanism of the expansion of silica glass upon exposure to moisture
Molecular mechanism of the expansion of silica glass upon exposure to moisture
复制标题
石英玻璃遇湿膨胀的分子机制
DOI：
10.1111/jace.16923
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发表时间：
2020
影响因子：
3.9
通讯作者：
M. Homann
中科院分区：
文献类型：
--
作者：
S. Garofalini;J. Lentz;M. Homann
几十年来，水与无定形二氧化硅(a-二氧化硅)表面接触并渗透到次表面的行为引起了人们极大的兴趣。1-24总的来说，水被证明在低于正常断裂应力的应力下通过应力腐蚀开裂削弱了二氧化硅的拉伸。这种行为是由通常已知的水分子通过Michalske-Freiman模型断裂裂尖上的应变硅氧烷键的反应引起的，从而使裂纹能够扩展。4，5 MichalskeFreiman模型假设具有小的二元和三元硅氧烷环，具有小的硅氧烷(Si-O-Si)键角，这表明在暴露于水中时显著增加了键断裂。3然而，Tomozawa将二氧化硅强度的下降归因于分子水的存在和表面结构松弛。25基于他们的高频Si-O不对称变化的IR数据收到：2019年9月9日|修订：2019年10月25日|接受：2019年11月17日DOI：10.1111/jace.16923
The behavior of water in contact with amorphous silica (a-silica) surfaces and penetration into the subsurface has garnered significant interest over many decades.1‒24 In general, water has been shown to weaken silica in tension via stress corrosion cracking at a stress less than the normal fracture stress. Such behavior is caused by the commonly known reaction of a water molecule rupturing the strained siloxane bonds at a crack tip via the Michalske-Freiman model, enabling propagation of the crack.4,5 The MichalskeFreiman model assumes small twoand three-membered siloxane rings that have small siloxane (Si–O–Si) bond angles that show significantly increased bond rupture upon exposure to water.3 However, Tomozawa attributed degradation in strength of silica to the presence of molecular water and surface structural relaxation.25 Based on their IR data of changes in the high-frequency Si–O asymmetric Received: 9 September 2019 | Revised: 25 October 2019 | Accepted: 17 November 2019 DOI: 10.1111/jace.16923