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

Auteur(s): Genix A.-C.(Corresp.), Bocharova Vera, Carroll Bobby, Dieudonne-George P., Chauveau E., Sokolov Alexei p., Oberdisse J.

(Article) Publié: Acs Appl. Mater. Interfaces, vol. 15 p.7496–7510 (2023)

DOI: 10.1021/acsami.2c18083
WoS: WOS:000924061800001

Fundamental understanding of the 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 (NP) 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 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 spacings and segmental dynamics provides unprecedented insights into the effect of surface modification on the main characteristics of PNCs: particle interactions and polymer interfacial layers.