Surface-engineered biphasic nanocomposites with interlocking friction for ultraefficient shear thickening

Efficient biphasic nanostructures enable interlocking friction in shear thickening fluids. • Surface-engineered ZnO–SiO 2 hybrids achieve 192% viscosity enhancement under shear. • Kevlar/STFs/PU composites exhibit 284% higher impact resistance via interface design. • Provides a meaningful application scenario for smart, lightweight protection under dynamic loading. Shear thickening fluids (STFs) hold significant promise for advanced impact-resistant applications; however, their performance is fundamentally constrained by limited particle–particle interactions within conventional colloidal systems. Herein, we propose an efficient materials design strategy based on surface-engineered biphasic nanocomposites, which synergistically integrate anisotropic ZnO nanorods with isotropic spherical nanoparticles to construct an interlocking frictional network. This engineered hybrid architecture enhances stress-induced particle coupling by promoting directional interfacial friction and geometric confinement, thereby fundamentally modulating the shear thickening mechanism. Rheological analyses reveal that the STFs formulated with these composite nanoparticles (CNP-based STFs) exhibit a remarkable 192% enhancement in maximum viscosity compared to conventional silica-based STFs. This is attributed to the emergence of a geometrically confined domain effect, wherein anisotropic–isotropic particle interlocking facilitates efficient stress transfer and energy dissipation under dynamic shear. Furthermore, when integrated into Kevlar/polyurethane (PU) composite fabrics, the CNP-based STFs deliver a significant 284% improvement in impact resistance relative to pristine Kevlar, and a 43% enhancement compared to Kevlar/PU composites without STFs infusion. This study not only elucidates the critical role of surface roughness, interfacial adhesion, and particle anisotropy in governing shear thickening behavior but also demonstrates a robust and scalable strategy for designing high-performance STFs. The insights gained herein open new avenues for the development of next-generation adaptive, high-efficiency protective materials for applications in personal armor, aerospace, and soft robotics. Download: Download high-res image (130KB) Download: Download full-size image