Bistable adhesion behavior of an anisotropic particle on a sliding polymer brush.

Bistable adhesion behavior of an anisotropic particle adsorbed on a sliding polymer brush was found by a single chain in mean field theory (SCMFT) study. Adjacent to the normal adhesion state at which the entropy is depressed, an additional abnormal adhesion state appears. The numerical results demonstrate that the physical mechanism of the bistable adhesion behavior is from the cooperation of the reptation motion of the sliding polymers and the rotating motion of the anisotropic particle. In the abnormal adhesion state, the orientational entropy of the anisotropic particle dominates the adhesion behavior, although the translational entropy is depressed. This bistable adhesion behavior works like a lasso rope in that the abnormal state provides a wide, sensitive, and responsive range, and the normal state furnishes stable adhesion depending on the particle anisotropy.