KINETIC CROSSOVER OF ROUGH-SURFACE GROWTH IN A COLLOIDAL SYSTEM

The scaling behavior of the surface of polystyrene colloidal particles depositing on the contact line between the colloidal latex film and t he glass substrate is studied. We analyzed the morphology of the forme d surface and the scaling exponents alpha and beta, defining the surfa ce width w(L,t)similar to L(alpha)f(t/L(alpha/beta)). The value of rou ghness exponent alpha changes fro 0.5 in a time regime to 0.71 at late r times of the depositing process. To our knowledge, this is the first experimental evidence of a crossover phenomenon of rough surface grow th in a colloidal system. The underlying physical reason for this phen omenon is suggested.