Confinement Effects on Host Chain Dynamics in Polymer Nanocomposite Thin Films

Journal Article · Wed Sep 06 04:00:00 EDT 2017 · Macromolecules

DOI:https://doi.org/10.1021/acs.macromol.7b01066· OSTI ID:1421677

Johnson, Kyle J. ^[1]; Glynos, Emmanouil ^[1]; Maroulas, Serafeim-Dionysios ^[2]; Narayanan, Suresh ^[3]; Sakellariou, Georgios ^[2]; Green, Peter F. ^[4]

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1. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
2. Department of Chemistry, University of Athens, Panepistimiopolis, Zografou, Athens 15771, Greece
3. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
4. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States; National Renewable Energy Laboratory, Golden, Colorado 80401, United States

Incorporating nanoparticles (NPs) within a polymer host to create polymer nanocomposites (PNCs) while having the effect of increasing the functionality (e.g.: sensing, energy conversion) of these materials, introduces additional complications with regard to the processing-morphology-function behavior. A primary challenge is to understand and control the viscosity of a PNC with decreasing film thickness confinement for nanoscale applications. Using a combination of X-ray photon correlation spectroscopy (XPCS) and X-ray standing wave based resonance enhanced XPCS to study the dynamics of neat poly-2-vinyl pyridine (P2VP) chains and the nanoparticle dynamics, respectively, we identified a new mechanism that dictates the viscosity of PNC films in the nanoscale regime. We show that while the viscosities of neat P2VP films as thin as 50 nm remained the same as the bulk, PNC films containing P2VP brush-coated gold NPs, spaced 50 nm apart, exhibited unprecedented increases in viscosities of over an order of magnitude. For thicker films or more widely separated NPs, the chain dynamics and viscosities were equal to the bulk values. These results -NP proximities and suppression of their dynamics -suggest a new mechanism by which the viscosities of polymeric liquids could be controlled for 2D and 3D nanoscale applications.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences; National Science Foundation (NSF)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1421677
• Journal Information: Macromolecules, Journal Name: Macromolecules Journal Issue: 18 Vol. 50; ISSN 0024-9297
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English