Dynamics at the Polymer/Nanoparticle Interface in Poly(2-vinylpyridine)/Silica Nanocomposites.

Journal Article · Wed Jan 01 00:00:00 EST 2014 · Macromolecules

DOI:https://doi.org/10.1021/ma5000317· OSTI ID:1128986

Holt, Adam P ^[1]; Griffin, Phillip ^[2]; Bocharova, Vera ^[1]; Agapov, Alexander L ^[1]; Imel, Adam E ^[1]; Dadmun, Mark D ^[1]; Sangoro, Joshua R ^[1]; Sokolov, Alexei P ^[1]

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1. ORNL
2. University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)

The static and dynamic properties of poly(2-vinylpyridine)/silica nanocomposites are investigated by temperature modulated differential scanning calorimetry, broadband dielectric spectroscopy (BDS), small-angle X-ray scattering (SAXS), and transmission electron microscopy. Both BDS and SAXS detect the existence of an interfacial polymer layer on the surface of nanoparticles. The results show that whereas the calorimetric glass transition temperature varies only weakly with nanoparticle loading, the segmental mobility of the polymer interfacial layer is slower than the bulk polymer by 2 orders of magnitude. Detailed analysis of BDS and SAXS data reveal that the interfacial layer has a thickness of 4 6 nm irrespective of the nanoparticle concentration. These results demonstrate that in contrast to some recent articles on polymer nanocomposites, the interfacial polymer layer is by no means a dead layer . However, its existence might provide some explanation for controversies surrounding the dynamics of polymer nanocomposites.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1128986
• Journal Information: Macromolecules, Vol. 47, Issue 5; ISSN 0024--9297
• Country of Publication: United States
• Language: English