Well-defined metal-polymer nanocomposites: The interplay of structure, thermoplasmonics, and elastic mechanical properties

Abstract

In this paper, Brillouin light scattering (BLS) characterization revealed an unusual decrease in the speed of sound in an Ag-polystyrene nanohybrid material with increasing filler content. The hybrid material possesses an isotropic and well-defined nanoparticle distribution based on its particle-brush architecture. Temperature-dependent BLS measurements reveal the unique contribution of local thermoplasmonic heating caused by the Ag nanoparticles exposed to laser irradiation. This reversible thermoplasmonic effect implies a lower apparent glass transition temperature (Tg) measured by means of BLS. Furthermore, irreversible aggregation and redispersion of the Ag nanoparticles were observed at temperatures much higher than Tg. This aggregation-redispersion effect is also reflected in a change of the mechanical properties, demonstrating its intimate interplay with the hybrid composite structure.