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

非技术描述：虽然多组分硅酸盐玻璃在各种先进的技术应用，很少有人知道它在潮湿环境中的表面化学。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理解复杂的玻璃，即使多组分硅酸盐的表面化学与二氧化硅明显不同。这是本研究的论文，硅酸盐玻璃上的水膜的结构和反应是玻璃表面组合物的函数，以及通过该表面创建的过程和施加的或残余的表面应力的存在。这项研究包括一系列精心设计的实验来验证这一假设。这项研究的成果不仅有利于玻璃科学领域，而且有利于其他工程技术，制造业和生命科学研究。考虑到与玻璃相关的工程和科学技术的广泛范围，它是一种理想的媒介，通过它来教育更广泛的社区关于材料。这项研究是通过参加夏季研究经验的本科生（REU）计划，提供短期课程，在历史上黑人大学，指导本科生以及代表性不足的少数民族学生的研究项目，并介绍年轻女性从高中到研究教育相结合。非技术描述：这项研究的过度假设是：（1）局部应力的存在，无论是固有的、施加的、残余的还是由于局部原子/分子结构，都是决定水层结构、其粘附性和其反应性的因素，以及（2）多组分硅酸盐玻璃上的水分子形成高度结构化的界面层，包括金属离子的水合，其作为玻璃表面的组成部分。非线性激光光谱和先进的热力学测量被用来直接测量厚度，结构和能量的化学吸附以及物理吸附的水层的多组分玻璃表面上的碱金属离子的浓度不同。 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附和摩擦引起的溶解有关。

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.