Colloidal Fluids Wetting Solid Surfaces

CTS-0100854 Darsh Wasan，Illinois Institute of Technology以前已经表明，在胶体颗粒存在的情况下，润湿区域由具有弯月面的主体流体和过渡区域组成，过渡区域导致结构化胶体颗粒的薄膜。 具有类似电荷的单分散乳胶颗粒的实验显示有序-无序颗粒结构的共存，这取决于相对于颗粒直径的膜厚度。 由于粒子的电荷相似，因此必须有某种形式的长程吸引力来产生有序结构。 提出了用显微干涉法测量薄膜厚度分布和计算接触线附近的毛细压力的方法。 将通过直接观察接触线附近薄膜内的有序微观结构来研究体积分数、颗粒尺寸、形状和多分散性对薄膜结构和稳定性的影响。 结构分离压力将从粒子径向分布函数和粒子相互作用的平均势计算。 接触角由毛细管压力的实验测量值和计算的分离压力计算。

CTS-0100854Darsh Wasan, Illinois Institute of TechnologyIt has been shown previously that in the presence of colloidal particles, the wetting region is comprised of the bulk fluid with the meniscus and the transition region leading to a thin film of structured colloidal particles. Experiments with similarly charged monodispersed latex particles show co-existence of ordered-disordered particle structures, depending on the film thickness relative to the particle diameter. Since the particles are similarly charged, there must be some form of long-range attractive force responsible for creating the ordered structure. Microintereferometric methods are proposed to be used to measure the film thickness profile and to calculate the capillary pressure near the contact line. The effect of volume fraction, particle size, shape and polydispersity on the film structure and stability will be investigated by direct observation of the ordered microstructure within the thin film near the contact line. The structural disjoining pressure will be calculated from the particle radial distribution function and the mean potential of particle interactions. The contact angle is calculated from experimentally measured values of the capillary pressure and the calculated disjoining pressure.