Moving interfaces in rod-like macromolecules

摘要

We present a model that describes mechanical unfolding behavior in rod-like macromolecules. We propose that the unfolding occurs via the motion of a folded/unfolded interface along the molecule. We predict the speed of this interface as a function of the pulling velocity such that the resulting force-extension curve replicates the overstretching transition typical of coiled coils and DNA. We model the molecules as one-dimensional continua capable of existing in two metastable states under an applied tension. The interface separates these two metastable states and represents a jump in stretch, which is related to the applied force by the worm-like chain relation. The Abeyaratne-Knowles theory of phase transitions in continua governs the mechanics of the interface.