8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Fri 911:10-14:00P4.39Influence of topology on effective potentials:coarse-graining ring polymersArturo Narros, 1 Angel J. Moreno, 2 and Christos N. Likos 11 Fakultät für Physik, der Universität Wien, Boltzmanngasse 5 A-1090, Wien,Austria2 Centro de Fisica de Materiales (CSIC-UPV/EHU), San Sebastian, SpainWe employ computer simulations and integral equation theory techniques to perform coarse- grainingof self-avoiding ring polymers with different knotedness and to derive effective inter- actionpotentials [1] between the centers of mass (CM) of these macromolecular entities. Different microscopicmodels for the monomer-monomer interactions and bonding are employed, bringing aboutan insensitivity of the effective interactions on the microscopic details and a convergence to a universalform for sufficiently long molecules. The pair effective interactions are shown to be accurateup to within the semidilute regime with additional, many-body forces becoming increasingly importantas the polymer concentration grows. The dramatic effects of topological constraints in theform of interaction potentials are going to bring forward and critically discussed [2]. We proposean explanation on these effective potentials considering the overlapping volume of two spheres.This explanation is able to reproduce the effective potential in the cases that we have considered.We further perform topology-preserving Monte-Carlo simulations of many ring polymers using theblob representation. Effective interaction potentials between CM of linear chains are used betweenblobs. These allow us to simulate more and bigger molecules, reaching higher concentrations andsaving computational time. We compare results from the blob picture and monomer resolution,so we can establish the rage of validity for blob technique, and also study the effect of topologyfor big ring polymers at moderate densities. [1] C. N. Likos, Physics Reports 348(4-5): 267-439(2001) [2] A. Narros, A. J. Moreno, and C. N. Likos, Soft Matter 6(11):2435 - 2441, (2010)39