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 a bove and below the Theta temperature was studied using the bond-fluctu ation model. Whereas above the Theta temperature only slight differenc es to the athermal (infinite temperature) limit occurred, the deformat ion behavior below the Theta temperature was found to be completely di fferent. The deformation is represented by a coil-strand coexistence a nd 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 b y the computation of several properties.