RANDOM SEQUENTIAL ADSORPTION OF SPHEROIDAL PARTICLES - KINETICS AND JAMMING LIMIT

Localized adsorption of hard (noninteracting) spheroidal particles on homogeneous interfaces was analyzed theoretically. In contrast to prev ious studies concentrated on flat (side on) adsorption in the present approach an unoriented (quasi-three-dimensional) adsorption of prolate and oblate spheroids was considered. By applying the random sequentia l adsorption (RSA) approach asymptotic analytic expressions were deriv ed for the available surface function (surface blocking parameter) and adsorption kinetics in the limit of low and moderate surface concentr ations. The range of validity of the approximate analytical results wa s determined by numerical simulations of adsorption kinetics performed using the Monte Carlo RSA technique. It was revealed by this comparis on that the analytical approximation can be used with a good accuracy for the dimensionless adsorption time tau smaller than two. The numeri cal calculations also enabled us to determine the maximum (jamming) su rface concentrations for unoriented adsorption of spheroids as a funct ion of the elongation or flattening parameter A. It was demonstrated t hat these jamming concentrations theta(infinity) are approached for lo ng adsorption times as tau(-1/4), therefore deviating considerably fro m the Langmuir model used often in the literature. (C) 1996 American I nstitute of Physics.