Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.64: Poster

Tuesday, March 8, 2005, 16:30–18:30, Poster TU D

Phase transitions of a single homopolymer chain from Monte Carlo simulations — •Federica Rampf, Wolfgang Paul, and Kurt Binder — Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany

The coil-globule transition of homopolymer chains has been studied since a long time. It is connected with the vanishing of the second virial coefficient for the effective interactions between the monomers of the chain and typically described theoretically using a truncated virial expansion. A more recent finding was that even simple, flexible homopolymer models can exhibit a first-order phase transition of the globular structure into an ordered phase.

Using an adaption of the Wang-Landau sampling method we determine the density of states for flexible polymer chains of the bond-fluctuation lattice model including attractive neighbour interactions. Analysis of the specific heat obtained from the density of states clearly reveals two distinct phase transitions. The one at the lower temperature develops into a δ-like singularity with increasing chain length exhibiting the first-order nature of this transition. A finite size scaling of the transition temperatures reveals that they agree in the thermodynamic limit. The effects of anchoring the chain on a neutral surface and confining it with another neutral surface are also discussed.