Surface methylation-regulated colloidal assembly of silica for scalable fabrication of anti-reflective superhydrophobic coatings

Surface methylation: Improves silica dispersion and uniform particle distribution during blade coating. • Colloidal assembly: Forms a homogeneous porous network for antireflection and superhydrophobicity. • Multifunctional coatings: Combine high transmittance, durability, superhydrophobicity, and enhanced PV efficiency. Controlling colloidal assembly for uniform film formation remains a key challenge in shear-driven coating processes for scalable fabrication of high performance silica coatings. Herein, a surface methylation strategy was proposed to modify the interfacial properties of silica nanoparticles, enabling controlled colloidal assembly and uniform film formation during blade coating. Surface methylation of fumed SiO 2 with dimethyldimethoxysilane (DMDMS) effectively reduces the surface energy and suppresses particle aggregation, resulting in enhanced dispersion stability and a more uniform particle distribution. Combined with solvent engineering using an EtOH/DMSO mixed solvent system, we promote uniform colloidal assembly during doctor blading, leading to the formation of a homogeneous porous network. This well-defined microstructure simultaneously provides refractive index matching for anti-reflection and surface roughness construction for superhydrophobicity. Consequently, the optimized coating exhibits high optical transparency in the visible region, with an average transmittance of 92.5% when referenced to air, a water contact angle exceeding 150°, and an increase in normalized photovoltaic conversion efficiency from 91% to 93.7%, In addition, the coating demonstrates reasonable durability under mild mechanical impact and abrasion. Importantly, the shear-assisted blade coating process provides a scalable approach for uniform film fabrication. This work establishes a direct correlation between surface methylation, colloidal assembly, and film formation, providing new physicochemical insight and a scalable strategy for multifunctional coating design. Download: Download high-res image (167KB) Download: Download full-size image