Measurement of interaction forces between colloids using AFM,and Clustering and ordering behavior.

首先，利用原子力显微镜(Nano Scope II；Digital Instruments)研究了在空气和水溶液中不同条件下云母表面与胶体颗粒(二氧化硅、乳胶和泡囊颗粒)的相互作用。通过将分散体滴在衬底上，将颗粒单层填充浇铸到肉质解理的云母表面。每一种分散体都形成了排列清晰的六角形薄膜，但二氧化硅粒子的轮廓比乳胶粒子的轮廓更清晰。乳胶膜的峰间距离小于单粒子的直径。如果云母表面不平整，则云母表面存在空隙，且与云母壁平行排列。其次，利用原子力显微镜测量了不同盐溶液中云母表面与球形胶体之间的作用力。该颗粒是一个半径为20微米的二氧化硅球体，被附着在显微镜下的力传感器上，力-距离曲线被确定为样品位移的函数。根据D.L.V.O.理论预测，在大分离度下，所测力呈指数衰减，衰减长度和静电势均随KCl浓度的增加而减小。此外，通过测量界面张力和块体中的粒度分布，考察了油/水或空气/水界面与某种胶体粒子(胶乳和泡囊粒子)的相互作用。此外，通过测量这些球形微粒的层化过程和表面压力-面积(pi-A)或膜厚-面积(d-A)曲线，研究了这些球形微粒在变薄的水膜内和清洁的汞表面上的相互作用。

Firstly, interaction between the mica surface and the some colloid particles (silica, latex and vesicle particles) were studied by the Atomic Force Microscope (Nano Scope II ; Digital Instruments) under the different conditions in air or aqueous solution. Particle monolayr fillms were cast onto fleshly cleaved mica surface by placing a drop of the dispersion onto the substrate. Every dispersions formed a clearly packed hexagonal film, but the contours of silica particles were clearer than those of latex particles. The peak-to peak distances of latex films were shorter than the diameter of the single particle. If the mica surface was uneven, there was a vacant space and an ordering array pararell to the mica-wall.Secondary, the forces between a mica surface and a spherical colloids were measured in the different salt solutions by use of the Atomic Force Microscope. The particle, a silica sphere of radius 20 mum, was attached to the force senser in the microscopy and force-distance curves were determined as a function of sample displacement. As predicted by D.L.V.O.theory, the measured forces decay exponentially at large separation, and both the decay length and electrostatic potential decrease with increasing KCl concentration.In addition, examination was made on the interaction between an oil/water or air/water interface and some kind of colloid particles (latex and vesicle particles) by measuring interfacial tensition and particle size distribution in the bulk. Furthermore, interactions between these spherical particlcs were studied inside the thinning aqueous film and on a clean mercury surface by measurfing the stratification process of these film and the surface pressure-area (pi-A) or film thickness-area (d-A) curves.