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arXiv · 2011.10976

Theory of polymer diffusion in polymer-nanoparticle mixtures: effect of nanoparticle concentration and polymer length

Bokai Zhang·Jian Li·Juan-mei Hu·Lei Liu
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Abstract

The dynamics of polymer-nanoparticle (NP) mixtures, which involves multiple scales and system-specific variables, has posed a long-standing challenge on its theoretical description. In this paper, we construct a microscopic theory for polymer diffusion in the mixtures based on a combination of generalized Langevin equation, mode-coupling approach, and polymer physics ideas. The parameter-free theory has an explicit expression and remains tractable on pair correlation level with system-specific equilibrium structures as input. Taking a minimal polymer-NP mixture as an example, our theory correctly captures the dependence of polymer diffusion on NP concentration and average interparticle distance. Importantly, the polymer diffusion exhibits a power law decay as the polymer length increases at dense NPs and/or long chain, which marks the emergence of entanglement-like motion. The work provides a first-principle theoretical foundation to investigate dynamic problems in diverse polymer nanocomposites.

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Bokai Zhang, Jian Li, Juan-mei Hu, Lei Liu. 2020-11-22. Theory of polymer diffusion in polymer-nanoparticle mixtures: effect of nanoparticle concentration and polymer length. https://doi.org/10.1039/d1sm00226k

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