Direct estimation of dynamic characteristics and interaction potential of latex particles interacting with a glass surface by evanescent wave light-scattering microscope method

Abstract

The dynamic and static characteristics of a polystyrene latex particle in dispersion interacting with a glass surface were studied by the evanescent wave light-scattering microscope (EVLSM) technique originally proposed by Prieve et al. for static studies. The dynamic behavior of the thermal vibration of the particle in a potential well created by electrostatic interaction between the particle and glass and gravity was clearly and quantitatively estimated, in addition to the estimation of the potential profile itself. The potential minimum became shallower with increasing added salt concentration. It was also clearly observed that the vibrational motion of the particle in the well became large in amplitude and the probability of the occurrence of the large vibration became large with increasing salt concentration. Such information on the dynamics is essential for the correct under-standing of the interaction potential. The EVLSM method is shown to be a very powerful technique for the estimation of not only the potential profile but also dynamic characteristics.