How Tuning Interfaces Impacts the Dynamics and Structure of Polymer Nanocomposites Simultaneously

Anne-Caroline Genix (1) , Vera Bocharova , Bobby Carroll , Philippe Dieudonné-George (1) , Edouard Chauveau (1) , Alexei Sokolov , Julian Oberdisse (2)

1 L2C - Laboratoire Charles Coulomb
2 L2C - Laboratoire Charles Coulomb

Fundamental understanding of macroscopic properties of polymer nanocomposites (PNCs) remains difficult due to the complex interplay of microscopic dynamics and structure, namely interfacial layer relaxations and three-dimensional nanoparticle arrangements. The effect of surface modification by alkyl methoxysilanes at different grafting densities has been studied in PNCs made of poly(2-vinylpyridine) and spherical 20 nm silica nanoparticles (NPs). The segmental dynamics has been probed by broadband dielectric spectroscopy, and the filler structure by small-angle X-ray scattering and reverse Monte Carlo simulations. By combining the particle configurations with the interfacial layer properties, it is shown how surface modification tunes the attractive polymer-particle interactions: bare NPs slow down the polymer interfacial layer dynamics over a thickness of ca. 5 nm, while grafting screens these interactions. Our analysis of interparticle spacing and segmental dynamics provides unprecedented insight into the effect of surface modification on the main characteristics of PNCs: particle interactions and polymer interfacial layers.

Mots clés: Surface modification; interfacial gradient; interparticle spacing distribution; segmental dynamics; interfacial layer thickness; colloidal silica; silane; poly(2-vinylpyridine)

Domaines: Matière Molle [cond-mat.soft]

Anne-Caroline Genix, Vera Bocharova, Bobby Carroll, Philippe Dieudonné-George, Edouard Chauveau, et al.. How Tuning Interfaces Impacts the Dynamics and Structure of Polymer Nanocomposites Simultaneously. ACS Applied Materials & Interfaces, 2023, 15 (5), pp.7496-7510. ⟨10.1021/acsami.2c18083⟩. ⟨hal-04244949⟩