Fluorine-free, liquid-repellent surfaces made from ionic liquid-infused nanostructured silicon

ABSTRACT: Liquid-repellent surfaces based on slippery liquid-infused porous substrates (SLIPS) were prepared from porous, nanostructured silicon surfaces with different surface functionalization, infused with the polar ionic liquid 1-ethyl-3-methylimidazolium methylsulfate ([C(2)mim]MeSO(4)). Contrary to nonpolar SLIPS based on perfluorinated substrates and infusion liquids, [C(2)mim]MeSO(4) forms stable SLIPS with high energy surfaces like native silicon (Si–SiO(2)) or ionic liquid-functionalized silicon (Si-[C(3)mim]Cl), whose liquid-repellent properties against low surface tension liquids (toluene, cyclohexane) were demonstrated by very low sliding angles (α < 3°) and low contact angle hysteresis (Δθ < 10°). These polar, ionic liquid-based SLIPS present a promising, environmentally benign extension of liquid-infused substrates to natural, high-energy oxide surfaces. GRAPHICAL ABSTRACT: [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00706-016-1888-2) contains supplementary material, which is available to authorized users.