Issue
EPL
Volume 87, Number 4, August 2009
Article Number 40002
Number of page(s) 5
Section General
DOI http://dx.doi.org/10.1209/0295-5075/87/40002
Published online 02 September 2009
EPL, 87 (2009) 40002
DOI: 10.1209/0295-5075/87/40002

Statistical mechanics of aggregation and crystallization for semiflexible polymers

C. 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

junghans@mpip-mainz.mpg.de
m.bachmann@fz-juelich.de
Wolfhard.Janke@itp.uni-leipzig.de

received 27 March 2009; accepted in final form 3 August 2009; published August 2009
published online 2 September 2009

Abstract
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.

PACS
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.

© EPLA 2009