POLYMER STATISTICS .5. SIMULATION OF POLYELECTROLYTES ADSORBED ON NEGATIVE SURFACE

We study the geometrical properties of negative-charged linear polyele ctrolytes adsorbed on a negative surface (NONS) by using the recently developed simulation method based on the cluster variation method (CVM ). This new method has the advantage of the analytical calculation whi ch is based on the equilibrium conditions. At the same time, we can ge t geometrical information that pure analytical calculations cannot giv e. Using our simulation method, we find that short chains are preferen tially adsorbed, and that the average length of the adsorbed chain is smaller than the average in the solution. The NONS has long tails exte nding into the solution and a very small area touching the surface. We report the molecular weight (i.e. the length) dependence of the end-t o-end distance, the distribution of those which are adsorbed, the laye r thickness, the fractions of train, tail and loop, and the average nu mber of tails. The results of this simulation show good qualitative ag reement with recent experiments on the adsorption of polyelectrolytes on negative-charged mica surfaces.