Hydrophobic and oleophobic anti-reflective polyacrylate coatings

•Fabrication of transparent pillar or pit grating covered acrylate coatings by UV-moulding.•Improved hydrophobic and oleophobic properties by modification with fluorosilane.•The submicron-structured coatings possessed anti-reflective and anti-wettable properties.•Both grating features demonstrated broadband antireflection over the visible spectrum.

This study focuses on design and fabrication of new UV-curable polyurethane acrylate submicron-structured coatings that have anti-reflective and anti-wettable surface properties. The coatings were replicated on PMMA substrates with use of a pair of nickel molds containing complementary surface patterns of submicron-sized pillars or pits in a cubic grid. The period of the square-shaped mold features was 270 nm and the height/depth of the grating features was 110 nm. The influence of the chemical composition and the replication accuracy on optical properties was examined by UV–Vis spectroscopy and variable angle spectroscopic ellipsometry. The UV-cured coatings showed a 1.5% reflectance between 400 and 700 nm of the visible spectral region. Transmittance was increased from 91% to 94% when the submicron-structure was copied onto the surface. Furthermore, the investigation of static and dynamic wetting of the coatings with water or oleic acid demonstrated that the sub-micron structure and chemical modification with fluoroalkylsilane significantly improved the water and oil resistance of the prepared coatings. Especially for pit-covered coatings, the static water contact angle increased to 146° and the highest advancing/receding contact angles for water were 150°/119°.

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