Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 1: Nanoparticles and Composite Materials I

CPP 1.10: Vortrag

Montag, 11. März 2013, 12:30–12:45, H34

effective interactions in polymer-nanoparticle composites and their resulted phase structures — •xuezheng cao¹, holger merlitz^1,2, and jens uwe sommer^1,3 — ¹Leibniz Institute für Polymerforschung Dresden, D-01069 Dresden, Germany — ²Department of Physics and ITPA, Xiamen University, Xiamen361005, P.R.China — ³Technische Universität Dresden, Institute of Theoretical Physics, D-01069 Dresden

We have studied polymer induced effective interactions between nanoparticle-nanoparticle and nanoparticle-substrate using molecular dynamics simulations. To analyze the entropic depletion potential, the polymer matrix above overlap concentration is regarded as a melt of concentration blobs. Convincing numerical evidence for the universal validity of scaling theory to describe the depletion potentials over a broad concentration range was found, and the directly measured depletion forces were well described with a scaling model in which the attraction between particles is caused by the depletion of concentration blobs. Adding enthalpic attraction between polymer-nanoparticle or polymer-nanoparticle can prevent the depletion effect. A thermodynamically stable dispersion of nanoparticles within polymer solution is verified to be possible by tuning the attraction strength between polymer and nanoparticle. We show that nanoparticles have a higher degree of order close to the substrate by increasing system temperature. This can be understood by scaling arguments showing the interplay between correlation blob and adsorption blob of polymers.