Monte Carlo simulations of a single polymer chain under extension above and below the Theta temperature

The deformation behavior of a single three-dimensional polymer chain above and below the Theta temperature was studied using the bond-fluctuation model. Whereas above the Theta temperature only slight differences to the athermal (infinite temperature) limit occurred, the deformation behavior below the Theta temperature was found to be completely different. The deformation is represented by a coil-strand coexistence and is therefore inhomogeneous. During the coil-strand coexistence the retractive force is independent of the extension. At large strains the coil-strand system becomes unstable; this instability was monitored by the computation of several properties.