A simple model for the mechanical stretching of (bio)polymers

It is proposed that the mechanical stretching of (bio)polymers with volume interactions can be modelled by the Gross–Pitaiievski equation when the density can be treated in the continuum approximation. The model is used in conjunction with a Monte-Carlo simulation to demonstrate one of the simplest examples of temperature-induced coil-globule phase transitions in a polymer chain. In addition, it is shown that the model can be easily implemented in a lattice and contains the essential aspects of the mechanical response of folded polypeptides when the enthalpic contributions to the elasticity dominate over the entropy. The model can provide an alternative simplified description for the mechanical properties of single (bio)polymers, with the possibility of including dynamical effects and/or external potentials, without resorting to more sophisticated but time-consuming molecular dynamics simulations.