Dresden 2017 – wissenschaftliches Programm
CPP 11.6: Vortrag
Montag, 20. März 2017, 16:15–16:30, ZEU 255
Depleted depletion drives polymer swelling in poor solvent mixtures — •Debashish Mukherji1, Carlos Marques2, Torsten Stuehn1, and Kurt Kremer1 — 1Max Planck Institute for Polymer Research, Mainz, Germany — 2Institut Charles Sadron, CNRS, Strasbourg, France
Macromolecular solubility in solvent mixtures often strike as paradoxical phenomena . In a system where all particle interactions are repulsive, chains can nevertheless collapse, due to increased repulsive monomer-solvent interactions that lead to an effective attraction between monomer units also known as depletion induced attraction. While it is well understood why a polymer can collapse in a purely repulsive solvent, polymer swelling at intermediate mixing ratios of two repulsive solvents still lacks a microscopic explanation. Here, for binary solvent mixtures, we combine computer simulations and theoretical arguments to unveil the microscopic, generic origin of this collapse-swelling-collapse scenario. We show that this phenomenon naturally emerges at constant pressure in mixtures of purely repulsive components when a delicate balance of the entropically driven depletion interactions is achieved .  D. Mukherji, C. M. Marques, and K. Kremer, Nature Communications 5, 4882 (2014).  D. Mukherji, C. M. Marques, T. Stuehn, and K. Kremer, arXiv:1609.09839 (2016).