Entropic Repulsion and Local Order in Doubly Tethered Polymers on a Surface

Abstract

The behavior of (athermal) mobile doubly tethered polymers (ring-like in 3D) is investigated, on a 2D substrate using the bond fluctuation model. The end-monomers can move laterally within a constrained distance range. Conformational properties of loop polymers are analyzed and specifically the ordering of the 2D system of end-monomers. For this, the director is considered between the end-monomers for local ordering. As tethering density increases, a transition from mushroom-like conformations to nearly upright structures is observed, as is the case for linear grafted polymers. The effects of loop repulsion are explored, i.e., entropic repulsion, and tethering density on the order parameter and orientational correlations of the directors in 2D. Despite the lack of a global phase transition, local orientational order emerges in 2D due to loop interactions in 3D.