Coupling between adsorption and the helix-coil transition

Biological and synthetic polymer molecules exhibit both the diffuse conformational helix-coil transition and adsorption phase transition near surfaces. Using an exactly solvable model, we have studied the coupling between these phenomena. Competition among entropic stabilization of loops, energetic stabilization of helical segments, and preferential adsorption of helices to surfaces results in a previously unknown rich phase diagram. The coupling promotes the helix-coil transition into a critical phenomenon and the adsorption transition becomes first order.