Spiky-Surfaced Mesoporous Silica Nanoparticles for Reinforced Elastomer Composites with Improved Interfacial Stability

Abstract

Inspired by the enhanced attachment of spiky structures in nature, a toughening strategy for polymer nanocomposites has been developed, which operates by improving the interfacial stability between polymer chains and nanoparticles with a hierarchical architecture combining accessible mesoporosity with spiky surfaces. However, engineering nanoparticles with such architectures remains difficult because epitaxial growth blocks pores and etching damages the mesostructures. Here, we report a condensation-induced anisotropic contraction strategy for constructing silica nanoparticles with a hierarchical architecture of an internal, center-radial mesoporous structure and conical-spiky surface. The incorporation of these nanoparticles into Sylgard 184 resulted in an increase of 2.1-fold tensile strength and 8.5-fold toughness compared to the pristine control. The fracture surfaces exhibited tortuous crack propagation, branching, and larger pull-out cavities than the nonspiky counterpart. It is proposed as a reinforcing mechanism involving interfacial entanglement between the spiky surface and polymer chains, which may enable dynamic chain sliding and facilitate energy dissipation during stretching.