Force Spectroscopy of Self-Associating Homopolymers

Abstract

This paper presents a theoretical and simulation investigation into the force–extension behavior of self-associating homopolymers. In particular, we show how long-lasting associations induce a transition in the stretching response of a single polymer from a freely jointed chain behavior (fast kinetics) to a highly dissipative unfolding pathway (slow kinetics). We identify the “shortest chain” through the associating network as the critical coordinate, and use a master equation approach to develop theory that describes the force–extension behavior of any chain. We elaborate on the properties of this theory, and consider two contrasting cases in which it applies, a random self-associating homopolymer and a self-associating helix. The theoretical predictions for both cases are in excellent agreement with the simulation results, demonstrating that the theory captures the essential physics governing the force spectroscopy of self-associating polymers. The disparate behaviors between the two topologies consider...