Statistical approach to the unfolding of mechanically stressed biopolymers

The mechanical properties of structural biomaterials are determined by features at many length scales. One example is the presence of an organic adhesive in nacre. The organic material contains biopolymers with discrete domains that may unfold as the polymer is extended. A statistical model for the mechanical response of a single biopolymer with these characteristics is introduced and studied. The response to tensile strain under displacement-controlled and load-controlled conditions is examined. Under the assumption of irreversible unfolding, analytical expressions for the load at first unfolding were derived, and a transition in behavior was observed for fast and slow loading. For titin, under displacement controlled extension, this transition occurs at about 5.25 pm/s.