Surface Functionalisation of Nano- and Microparticles for Photocurable Composites

Surface functionalisation can alter how a nano- or microparticle is wetted by a photocurable resin, how it aggregates, how the formulation flows, how light and reactive species reach the interface, and how the cured network transfers stress across that interface. These outcomes are related but not interchangeable. A supplier treatment label, an infrared band or a stable suspension does not by itself prove covalent grafting, complete surface coverage, network coupling or retained composite performance. This review defines a qualification architecture that follows the particle from incoming surface state through treatment verification, wetting and dispersion, photopolymerisation, cured morphology and interface-sensitive properties. Primary studies on modified silica, alumina, zirconia, hydroxyapatite and glass fillers show the value of complementary chemical, thermal, colloidal, rheological, kinetic, microscopic and mechanical measurements. They also show that different endpoints can reach different extrema within the same formulation series. The evidence therefore supports matched untreated and treated controls, state-resolved measurements and formulation-specific acceptance boundaries. It does not support a universal coupling agent, treatment concentration, hydrolysis condition, mixing history, filler loading or process recipe.