Abstract
We have developed an algorithm for predicting the structure of monolayer films generated through the random sequential adsorption (RSA) by modifying a set of Ornstein-Zernike equations (OZ). This type of integral-equation theory has long been used to estimate the structures of equilibrium three-dimensional and two-dimensional fluids. It was then modified to compute the structures built in a non-equilibrium situation, which are that of fluids adsorbing within disordered quenched matrix. This finally leads to the successful algorithm for RSA. In this model, fluid particles are added at random onto a surface one at a time. Once it reaches the surface, if it does not overlap with previously adsorbed particles, it will irreversibly adsorbed at that position. If it overlaps, a new insertion attempt is provoked. A new cycle of adsorption continues in this fashion. Our previous work on RSA assumed that particles were spheres of the same size. However, colloidal particles and bioparticles are of various sizes by nature. In this work, we, therefore, study the effect of size polydispersity on the structures of the monolayer films by incorporating the size distribution of spherical particles along with their corresponding interaction potentials to the set of our OZ equations. The distribution could be totally at random in certain diameter range. Together with appropriate closures such as Percus-Yevick approximation, we compute for the radial distribution functions from the integral equations. The results are in good agreements with ones obtained from Monte Carlo simulation.
