title: A theoretical study of dispersion-to-aggregation of nanoparticles in adsorbing polymers using molecular dynamics simulations.
abstract: The properties of polymer-nanoparticle (NP) mixtures significantly depend on the dispersion of the NPs. Using molecular dynamics simulations, we demonstrate that, in the presence of polymer-NP attraction, the dispersion of NPs in semidilute and concentrated polymers can be stabilized by increasing the polymer concentration. A lower polymer concentration facilitates the aggregation of NPs bridged by polymer chains, as well as a further increase of the polymer-NP attraction. Evaluating the binding of NPs through shared polymer segments in an adsorption blob, we derive a linear relationship between the polymer concentration and the polymer-NP attraction at the phase boundary between dispersed and aggregated NPs. Our theoretical findings are directly relevant for understanding and controlling many self-assembly processes that use either dispersion or aggregation of NPs to yield the desired materials.
authors.affiliation: Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, P.R. China. xzcao@zstu.edu.cn.
authors.forename: Xue-Zheng
authors.initials: XZ
authors.lastname: Cao
authors.affiliation: Department of Physics and ITPA, Xiamen University, Xiamen 361005, P.R. China and Leibniz-Institut für Polymerforschung Dresden, 01069 Dresden, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Merlitz
authors.affiliation: Department of Physics and ITPA, Xiamen University, Xiamen 361005, P.R. China.
authors.forename: Chen-Xu
authors.initials: CX
authors.lastname: Wu
authors.affiliation: Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, P.R. China. xzcao@zstu.edu.cn and Department of Engineering Materials University of Sheffield Mappin Street, Sheffield S1 3JD, UK.
authors.forename: Goran
authors.initials: G
authors.lastname: Ungar
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden, 01069 Dresden, Germany and Technische Universität Dresden, Institute of Theoretical Physics, D-01069 Dresden, Germany.
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Sommer