Dual-wavelength reflection interference contrast microscopy (DW-RICM) is established as a microinterferometric technique to measure absolute optical distances between transparent planar substrates and hard or soft surfaces such as colloidal beads or artificial and biological membranes, which hover over the substrate. In combination with a fast image processing algorithm the technique was applied to analyze the trajectories of colloidal beads sedimenting under gravity. As the beads approach the surface of the substrate, they slow down because of hydrodynamic coupling of the bead motion to the substrate. The effective surface friction coefficients were measured as a function of the absolute distance of the beads from the surface. The height dependence of the friction coefficient was found to be in quantitative agreement with previous theoretical predictions. Furthermore, we demonstrate that the DW-RICM technique allows the determination of the height of membranes above substrates and the amplitude and direction of height fluctuations. Without any further need to label the membrane the unambiguous reconstruction of the surface profile of soft surfaces is possible.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据