Relative Size of the Polymer and Nanoparticle Controls Polymer Diffusion in All-Polymer Nanocomposites

Journal Article · Tue Mar 26 04:00:00 EDT 2019 · Macromolecules

DOI:https://doi.org/10.1021/acs.macromol.8b02596· OSTI ID:1505300

Martin, Halie J. ^[1]; White, B. Tyler ^[2]; Yuan, Guangcui ^[3]; Saito, Tomonori ^[2]; Dadmun, Mark D. ^[4]

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

The dynamics of polymers in an all-polymer nanocomposite that are composed of soft cross-linked polystyrene nanoparticles and linear polystyrene have been examined. In this article, we describe how the relative size of the nanoparticle to that of the polymer chain and its rigidity impact the linear polymer chain diffusion. The results of the in situ neutron reflectivity experiments show three distinct regimes in the linear polymer diffusion. The results indicate that the inclusion of soft nanoparticles increases the amount of topological constraints and confinement effects for low matrix molecular weight polymer. At modest molecular weights where the size of the nanoparticle and polymer chain are similar, the soft nanoparticles neither inhibit nor enhance the linear polymer diffusion, while at the highest polymer matrix molecular weight, the linear polymer diffusion increases due to an increase in the constraint release mechanism by the soft nanoparticles. Thermal analysis demonstrates that the nanoparticles do not increase the free volume of the system nor do they behave as a plasticizing agent. These results are interpreted to indicate that the competition between a topological barrier effect and enhancing constraint release defines the behavior of a given all-polymer nanocomposite.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1505300
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: 7 Vol. 52; ISSN 0024-9297
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
77 NANOSCIENCE AND NANOTECHNOLOGY