Fabrication of antireflective coatings with self-cleaning function via in situ polymerization of Si-Ti modified hollow silica nanoparticle mixed sol

This study fabricated single-layer antireflective coatings (ARCs) employing a Si-Ti modified hollow silica nanoparticle (HSN) sol with self-cleaning function via in situ polymerization. Both shell-like and chain-like SiO₂–TiO₂ composites were directly synthesized in an alkali-catalyzed hollow SiO₂ sol through acid catalysis, which endowed the coating with suitable hardness while maintaining higher transmittance, thereby improving its overall performance. The influence of varying Si-Ti precursor doping ratios on the surface morphology, structure, optical performance, mechanical strength, and wettability of the coatings was investigated. The resulting coatings exhibited superhydrophilic properties, with a minimum water contact angle (WCA) below 5°. At an optimal doping concentration of 15 wt%, the coating achieved a hardness of 3 H and a solar-weighted transmittance (T_sw) exceeding 95.49 % across the wavelength range of 380–1100 nm, markedly surpassing that of the K9 glass (T_sw = 91.70 %). At this doping level, the self-cleaning capability, antifogging performance, and environmental durability of the coating were further analyzed. The coating reached a self-cleaning efficiency of 95.93 % and a slight decrease of 0.03 % in T_sw. After steam condensation experiment (sample placed above deionized water at 90 ℃ for 1 min), the haze value remained below 2 %. After 30 days of damp testing (80 % RH at 25 ℃), the reduction in T_sw was only 0.07 %. After 100 thermal cycles (−20 ℃/30 %RH ↔ 100 ℃/30 %RH, each condition held for 30 min), T_sw decreased by 0.3 %.