Molecular UHV-FTIR studies of adsorbate covered TiO2-microparticle surfaces

吸附物覆盖的 TiO2 微粒表面的分子 UHV-FTIR 研究

• 批准号: 169597163
• 负责人: Professor Dr.-Ing. Guido Grundmeier
• 金额: --
• 依托单位: Arbeitskreis Technische und Makromolekulare Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/169597163?language=en
• 关键词: Molecular; UHV; FTIR; studies; adsorbate

The project aims at the study of contact forces between particles and oxidic substrates based on the molecular control of the adsorbate structure concerning the orientation, thickness and mobility via AFM based and spectroscopic techniques. As model systems, SiO2 and TiO2 will be used as their surface modification is of high interest for the flow properties of particle powders.The methodology is based on the hypothesis that ultrahigh vacuum (UHV) and also clean liquid phases allow for the adjustment of the interfacial chemistry of particles without the influence of environmental contaminations. Furthermore the AFM colloidal probe technique as a force analytical method allows in both media the quantification of the influence of this interface structure on the interaction in the contact zone of the particles.As organic adsorbates organophosphonic acids will be used, as they are of large interest for the tailoring of surface properties of the considered particles and enable the preparation of monolayers of different ordering and chemical functionality. The adsorption of water on bare or chemically modified surfaces is done at the interface to ultrahigh vacuum or an organic liquid phase.The UHV analytical setup includes an X-ray photoelectron spectrometer (XPS) for the analysis of the adsorbate chemistry and an UHV-AFM which allows the measurement of contact forces on bare and adsorbate covered surfaces. A particular interest is the mobility and ordering of the adsorbate layers as a function of the chemical properties and temperature. By means of atmospheric AFM the formation of capillary bridges and their influence on contact forces as a function of surface chemistry and temperature is investigated. To avoid the influence of atmospheric adsorbates, the experiments will be performed in an apolar, organic phase with a controlled activity of water. Hence at hydrophilic interfaces different amounts of water will be available for the temperature dependent interaction involving ice-like water layers of capillary bridges. Via in-situ FTIR spectroscopy and in-situ surface plasmon resonance these water layers will be characterized concerning their thickness and structure.

该项目的目的是根据吸附物结构的分子控制粒子和氧化底物之间的接触力研究，该结构涉及通过基于AFM和光谱技术的方向，厚度和迁移率。作为模型系统，SIO2和TIO2将被使用，因为它们的表面修饰对颗粒粉的流量具有很高的兴趣。该方法基于以下假设：超高真空（UHV）及其清洁液相也可以调节颗粒的界面化学，没有环境污染的影响。此外，AFM胶体探针技术是一种力分析方法，在两种介质中都可以量化该界面结构对颗粒接触区中相互作用的影响。有机可吸附有机磷酸将使用，因为它们具有很大的兴趣为了定制所考虑颗粒的表面特性，并可以制备不同有序和化学功能的单层。水上在裸露或化学修饰的表面上的吸附是在界面上对超高真空或有机液相进行的。UHV分析设置包括X射线光电子光谱仪（XPS），用于分析通闻型化学和UHV-AFM AFM这允许测量裸露和吸附物覆盖的表面上的接触力。一个特别的兴趣是吸附物层的迁移率和顺序是化学性质和温度的函数。通过大气中，研究了毛细管桥的形成及其对接触力的影响，其影响是表面化学和温度的函数。为了避免大气吸附物的影响，实验将在具有控制水活性的极性，有机相中进行。因此，在亲水界面，不同量的水将用于涉及毛细管桥的冰状水层的相关相互作用。通过原位FTIR光谱和原位表面等离子体共振，这些水层将被表征有关其厚度和结构的特征。