Title: Polymer Chain Diffusion in All-Polymer Nanocomposites: Confinement vs Chain Acceleration

Abstract

All-polymer nanocomposites, in which soft, polymer-based nanoparticles are dispersed in the polymer matrix, have received great interest lately due to their potential use in a range of applications, including drug delivery and self-healing materials. However, the impact of this new class of nanoparticles on the dynamics of a linear polymer matrix in an all-polymer nanocomposite is still largely unknown. In this work, we report that the addition of polystyrene soft nanoparticles accelerates the diffusion of high molecular weight linear PS chains over a range of nanoparticle loadings. Our results show that at nanoparticle loadings below 1%, the diffusion of the linear matrix increases, presumably via a constraint release mechanism. At loadings above 1%, the increase in diffusion is mitigated by confinement effects of the nanoparticles. Thus, the response of these all-polymer nanocomposites is dominated by the balance of entropic confinement of the chain, which slows diffusion and a constraint release mechanism that speeds up the diffusion. However, the diffusion of the linear chain in the all-polymer nanocomposite is faster than that of the same chain in the melt at all loadings, diverging from the behavior of most nanocomposites with hard, impenetrable nanoparticles. Thus, the mechanism that accelerates the chain diffusionmore » dominates in these systems. This behavior is unusual and fundamentally different than what has been reported for nanocomposites with hard inorganic nanoparticles, indicating that new perspectives are needed for these materials where the control of loading can either accelerate or decelerate the dynamics of the matrix in a distinctive manner.« less

Authors:

Rostom, Sahar ^[1]; White, B. Tyler  ^[2];

• Search DOE PAGES for author "White, B. Tyler"
• Search DOE PAGES for ORCID "0000-0002-0266-1238"

Yuan, Guangcui ^[3]; Saito, Tomonori  ^[2];

• Search DOE PAGES for author "Saito, Tomonori"
• Search DOE PAGES for ORCID "0000-0002-4536-7530"

Dadmun, Mark D.  ^[4]

• Search DOE PAGES for author "Dadmun, Mark D."
• Search DOE PAGES for ORCID "0000-0003-4304-6087"

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+ Show Author Affiliations

1. Univ. of Tennessee, Knoxville, TN (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research; Georgetown Univ., Washington, DC (United States)
4. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Publication Date:

Wed Jul 29 00:00:00 EDT 2020

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

OSTI Identifier:

1840214

Grant/Contract Number:  

AC05-00OR22725; DMR-0944772

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 124; Journal Issue: 34; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Diffusion; Polymer chains; Nanoparticles; Nanocomposites; Polymers