Polymer statistics. V. Simulation of polyelectrolytes adsorbed on negative surface

We study the geometrical properties of negative-charged linear polyelectrolytes 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 which is based on the equilibrium conditions. At the same time, we can get geometrical information that pure analytical calculations cannot give. Using our simulation method, we find that short chains are preferentially adsorbed, and that the average length of the adsorbed chain is smaller than the average in the solution. The NONS has long tails extending into the solution and a very small area touching the surface. We report the molecular weight (i.e. the length) dependence of the end-to-end distance, the distribution of those which are adsorbed, the layer thickness, the fractions of train, tail and loop, and the average number of tails. The results of this simulation show good qualitative agreement with recent experiments on the adsorption of polyelectrolytes on negative-charged mica surfaces. © 1993.

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