Abstract
A new class of conductive composite materials, solvent-free ionically grafted nanoparticles, were modeled by coarse-grained molecular dynamics methods. The grafted oligomeric counterions were observed to migrate between different cores, contributing to the unique properties of the materials. We investigated the dynamics by analyzing the dependence on temperature and structural parameters of the transport properties (self-diffusion coefficients, viscosities and conductivities) and counterion migration kinetics. Temperature dependence of all properties follows the Arrhenius equation, but chain length and grafting density have distinct effects on different properties. In particular, structural effects on the diffusion coefficients are described by the Rouse model and the theory of nanoparticles diffusing in polymer solutions, viscosities are strongly influenced by clustering of cores, and conductivities are dominated by the motions of oligomeric counterions. We analyzed the migration kinetics of oligomeric counterions in a manner analogous to unimer exchange between micellar aggregates. The counterion migrations follow the "double-core" mechanism and are kinetically controlled by neighboring-core collisions. © 2013 The Royal Society of Chemistry.
Original language | English (US) |
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Pages (from-to) | 6091 |
Journal | Soft Matter |
Volume | 9 |
Issue number | 26 |
DOIs | |
State | Published - 2013 |
Externally published | Yes |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledged KAUST grant number(s): KUSC1-018-02
Acknowledgements: This publication is based on work supported by Award no. KUSC1-018-02, made by King Abdullah University of Science and Technology (KAUST). Simulations were performed primarily on the Della cluster of the TIGRESS High Performance Computing Center at Princeton University. The authors would like to thank Profs. Emmanuel Giannelis, Lynden Archer, Donald Koch, Fernando Escobedo and Alissa Park for helpful discussions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.