REG: Acquisition of an Atomic Force Microscope for the Study of Adsorbed Layers on Solids

摘要CTS-9809053 Somasundaran，P.哥伦比亚U. 固体的表面改性在许多传统和新兴的工业过程中起着至关重要的作用，这些过程依赖于界面现象，例如粘附、润湿、润滑、电沉积、催化和聚集/分散。 通过吸附进行化学改性是控制胶体体系界面行为的一种很好的手段。 过去对表面活性剂和聚合物在固体矿物上吸附的研究表明，这些物质之间的相互作用导致聚集，对界面行为有显着影响。 使用多管齐下的方法相结合的传统技术的吸附，润湿性和润滑与先进的光谱技术的荧光，电子自旋共振和共振拉曼，我们已经提出了离子表面活性剂吸附单独在低浓度和集群在高浓度（半胶束，admicelles，solloids）2，3。 重要的是，吸附物种的重新取向已被提出发生在高浓度下。 这样的重新取向和重构可以具有剧烈的影响，例如，在润湿性和粘附性方面，无机物被引入到系统中。 当添加剂（表面活性剂、聚合物和自旋共振技术）已经产生了关于固体上的团簇的极性、粘度和聚集数等微观性质的信息时，也可以发生荧光和电子重构，但是在表面聚集体演变的浓度范围内的分子尺度上的直接调查尚未完成。 过去进行的研究是在高于临界胶束浓度的较高浓度范围内进行的4，5。 一个有希望的创新允许这样的调查是扫描的发展 探针显微镜（SPM）。 SPM是一个通用名称，目前它包括扫描 隧道显微镜和原子力显微镜。 其他SPM技术 发展的仪器有扫描离子、磁力、光子扫描和热剖面仪 显微镜6. SPM的三维地形图绘制能力 真空、空气或液体中极高分辨率（原子级）的技术 环境无与伦比。 胶体体系中相互作用力的测量 从理论和实践的角度来看都很重要。 相互作用力 在SPM尖端和样品之间可以产生到目前为止还没有的信息。 可用于分散系统。 原子力显微镜的拟议收购将使我们能够直接探测吸附层原位及其结构的变化，由于化学和流体动力学因素。 这将显着提高我们的研究能力，因为同时使用原子力显微镜和其他技术将使我们能够深入了解纳米尺度上的界面过程。 这些信息还导致工程能力，以操纵和控制表面的吸附改性，以达到最佳效果。

ABSTRACT CTS-9809053 Somasundaran, P. Columbia U. Surface modification of solids plays a vital role in many traditional and emerging industrial processes dependent upon interfacial phenomena such as adhesion, wetting, lubrication, electrodeposition, catalysis and aggregation/dispersion. Chemical modification by adsorption offers an excellent means to control interfacial behavior of colloidal systems. Past work on adsorption of surfactants and polymers on solid minerals has shown that interactions among these species leading to aggregation can have marked effects on interfacial behavior1. Using a multipronged approach combining traditional techniques of adsorption, wettability and lubrication with advanced spectroscopic techniques of fluorescence, electron spin resonance and resonance Raman, we have proposed ionic surfactants to adsorb individually at low concentrations and in clusters at high concentrations (hemimicelles, admicelles, solloids)2,3. Importantly, reorientation of adsorbed species has been proposed to occur under high concentrations. Such reorientation and reconformation can have drastic effects, for example, in wettability and adhesion inorganics) are introduced into the system. While fluorescence and electron. Reconformation can also occur when additives (surfactants, polymers and spin resonance techniques have yielded information on such microproperties as polarity, viscosity and aggregation number of the clusters on solids, direct investigation on a molecular scale in the concentration range where surface aggregates evolve has not yet been done. Studies conducted in the past have been carried out in the higher concentration ranges above critical micelle concentration4,5. A promising innovation allowing such investigation is the development of scanning probe microscopy (SPM). SPM is a generic name and at present it includes scanning tunneling microscopy and atomic force microscopy. Other SPM techniques under development are scanning ion, magnetic f orce, photon scanning and thermal profiler microscopy6. The three dimensional topography-mapping capabilities of SPM techniques at extremely high resolution (atomic scale) in vacuum, air, or liquid environments are unparalleled. The interaction force measurements in colloidal systems are important both from a theoretical and practical point of view. The interaction force between the SPM tip and the sample can yield information which so far has not been obtainable for dispersed systems. The proposed acquisition of the atomic force microscope will enable us to directly probe the adsorbed layer in-situ and changes in its structure due to chemical and hydrodynamic factors. This will markedly increase our investigative capability since the use of atomic force microscope concurrently with other techniques will enable us to develop an understanding of interfacial processes on a nanoscale. Such information also leads to engineering capability to manipulate and control modification of surfaces by adsorption for optimum effect.