Deformation of a single polymer chain in two dimensions above and below the Theta temperature - A Monte Carlo study

The deformation behavior of a single two-dimensional polymer chain above and below the Theta-temperature was studied using the bond-fluctuation model, Above the Theta-temperature, the deformation behavior was found to be similar to that in the athermal (infinite temperature) limit. The entropy is the dominating part of the deformation. Below the Theta-temperature, the deformation is completely different, After a short linear force regime the total force becomes independent of the extension. In this regime the deformation is represented by a coil-strand coexistence, and therefore, inhomogeneous. At low temperatures, the energy dominates the deformation pattern. At large strains, the coil-strand system becomes unstable. Several properties were evaluated to monitor this behavior.