Glass Surface Chemistry - Understanding Effects of Alkali Ions on Water Activity on Glass

非技术描述：尽管多组分硅酸盐玻璃涉及各种先进的技术应用，但人们对其在潮湿环境中的表面化学知之甚少。因此，研究人员、工程师和制造商必须依靠与无定形二氧化硅相关的文献和分析方法来了解复杂玻璃，尽管多组分硅酸盐的表面化学显然与二氧化硅有很大不同。本研究的主题是硅酸盐玻璃表面水膜的结构和反应是玻璃表面组成、表面形成过程和存在外加或残余表面应力的函数。这项研究由一系列精心设计的实验组成，以检验这一假设。这一研究成果不仅将惠及玻璃科学领域，也将惠及其他工程技术、制造和生命科学研究。考虑到与玻璃有关的广泛的工程和科学技术，它是一个理想的媒介，通过它来教育更广泛的社区有关材料的一般知识。这项研究正在与教育相结合，参与了本科生暑期研究体验(REU)项目，在一所历史悠久的黑人大学开设了短期课程，指导本科生和少数族裔学生的研究项目，并引入高中的年轻女性参与研究。非技术描述：本研究的总体假设是：(1)局部应力的存在，无论是内在的、外加的、残留的还是由局部原子/分子结构引起的，是决定水层结构、其粘附性和反应性的一个因素，(2)多组分硅酸盐玻璃上的水分子形成了高度结构化的界面层，包括金属离子的水合作用，这是玻璃表面不可分割的一部分。非线性激光光谱和先进的热力学测量被用来直接测量不同浓度碱性离子的多组分玻璃表面的化学吸附水层和物理吸附水层的厚度、结构和能量。这些关于吸附水层的信息与多组分玻璃表面在潮湿环境中的粘合和摩擦诱导的溶解有关。

NON-TECHNICAL DESCRIPTION: Although multicomponent silicate glasses are involved in a variety of advanced technical applications, little is known about its surface chemistry in humid ambience. Thus, researchers, engineers and manufacturers must rely on literature and analytical methods relevant to amorphous silica to understand complex glasses even though it is clear that the surface chemistry of multicomponent silicate is quite different than silica. It is the thesis of this study that the structure and reaction of water films on silicate glasses are a function of the glass surface composition as well as the process through which the surface is created and the presence of applied or residual surface stress. This study consists of a series of carefully-designed experiments to test this hypothesis. The outcome of this research will benefit not only the glass science field, but also other engineering technologies, manufacturing, and life science research. Considering the broad range of engineering and science technologies that work with glass, it is an ideal medium through which to educate the broader community about materials, in general. This research is being integrated with education by participating in a summer Research Experiences for Undergraduates (REU) program, delivering short courses at a historically black university, mentoring undergraduate students as well as underrepresented minority students on research projects, and introducing young women from high school into research.NON-TECHNICAL DESCRIPTION: The over-arching hypotheses of this study are: (1) the presence of local stress, whether intrinsic, applied, residual or due to local atomic/molecular structure, is a factor in determining the water layer structure, its adhesion and its reactivity, and (2) water molecules on multicomponent silicate glasses form a highly-structured interfacial layer, including hydration of metal ions, which acts as an integral part of the glass surface. Non-linear laser spectroscopy and advanced thermodynamic measurements are being used to directly measure the thickness, structure and energy of the chemisorbed as well as physisorbed water layer on multicomponent glass surfaces with varying concentrations of alkali ions. This information about the adsorbed water layer is being related to the adhesion and friction-induced dissolution of multicomponent glass surfaces in humid ambience.