Title: Polymer Conformations and Diffusion Through a Monolayer of Confining Nanoparticles

Abstract

We present coarse-grained molecular dynamics simulations to probe chain-scale polymer conformations and diffusion between confining nanoparticles (NPs). By constructing a monolayer of hexagonally-packed NPs in a polymer melt with athermal interactions, we observe the magnitude and length-scale over which homogeneously confining NPs impact the polymer behavior, which provides fundamental insights into more complex polymer nanocomposites. We show that polymer conformations are more perturbed under strong confinement (i.e. when the interparticle distance, ID, is less than twice the polymer radius of gyration, 2R_g) as compared to around an isolated NP, and the effect depends on the ratio of R_NP/R_g rather than either independently. In fact, these conformations can be quantitatively replicated by executing a simple random walk in a similarly confining environment. We also show that polymer diffusion is slowed by the presence of NPs and the slowing persists far beyond the length-scale over which polymer conformations are perturbed. Although the slowing is strongest ~R_g from the NPs, the diffusion coefficient is slower even beyond ~5R_g from the NPs. Furthermore, by analyzing the directional van Hove distributions, we show polymer diffusion away from the NP monolayer is bulk-like while diffusion through the monolayer is slower with increasing NP confinement. Furthermore, thesemore » molecular dynamics simulations provide fundamental insights into the temporal and spatial effect of confining, athermal NPs on chain-scale polymer conformations and diffusion.« less

Authors:

Bailey, Eric J.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-7194-9035"
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Riggleman, Robert A.  ^[1];

• Search DOE PAGES for author "Riggleman, Robert A."
• Search DOE PAGES for ORCID "0000-0002-5434-4787"
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Winey, Karen I.  ^[1]

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• Search DOE PAGES for ORCID "0000-0001-5856-3410"
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+ Show Author Affiliations

1. University of Pennsylvania, Philadelphia, PA (United States)

Publication Date:

2020-09-14

Research Org.:

Univ. of Pennsylvania, Philadelphia, PA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation Graduate Research Fellowship Program

OSTI Identifier:

1656863

Alternate Identifier(s):

OSTI ID: 1797288

Grant/Contract Number:  

SC0016421; DGE1321851

Resource Type:

Accepted Manuscript

Journal Name:

Macromolecules

Additional Journal Information:

Journal Volume: 53; Journal Issue: 19; Journal ID: ISSN 0024-9297

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Polymer; conformation; diffusion; nanoparticles; confinement