COLLAPSE OF POLYMER BRUSHES INDUCED BY N-CLUSTERS

Certain water soluble polymers may have a repulsive two-body interaction, but afl attractive n-body interaction induced by certain ''clustering'' effects. In the bulk this may lead to a ''thetaBAR point'' in the phase diagram. Here, with polymer brushes, we construct the theoretical density profiles, using a local mean-field approximation. The brush often shows two layers (one dense near the wall, and one dilute), but the concentrations in both layers depend on the distance to the wall. The location of the interlayer boundary can be derived from a Maxwell construction.