Statistical mechanics of aggregation and crystallization for semiflexible polymersC. Junghans1, 2, M. Bachmann1, 3 and W. Janke1
1 Institut für Theoretische Physik and Centre for Theoretical Sciences (NTZ), Universität Leipzig Postfach 100 920, D-04009 Leipzig, Germany, EU
2 Max-Planck-Institut für Polymerforschung - Ackermannweg 10, D-55128 Mainz, Germany, EU
3 Institut für Festkörperforschung, Theorie II, Forschungszentrum Jülich - D-52425 Jülich, Germany, EU
received 27 March 2009; accepted in final form 3 August 2009; published August 2009
published online 2 September 2009
By means of multicanonical computer simulations, we investigate thermodynamic properties of the aggregation of interacting semiflexible polymers. We analyze a mesoscopic bead-stick model, where nonbonded monomers interact via Lennard-Jones forces. Aggregation turns out to be a process, in which the constituents experience strong structural fluctuations, similar to peptides in coupled folding-binding cluster formation processes. In contrast to a recently studied related proteinlike hydrophobic-polar heteropolymer model, aggregation and crystallization are separate processes for a homopolymer with the same small bending rigidity. Rather stiff semiflexible polymers form a liquid-crystal–like phase, as expected. In analogy to the heteropolymer study, we find that the first-order–like aggregation transition of the complexes is accompanied by strong system-size–dependent hierarchical surface effects. In consequence, the polymer aggregation is a phase-separation process with entropy reduction.
05.10.-a - Computational methods in statistical physics and nonlinear dynamics.
87.15.A- - Theory, modeling, and computer simulation.
87.15.Cc - Folding: thermodynamics, statistical mechanics, models, and pathways.
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