SummaryA rapid and cost-effective lithographic method, polymer blend lithography (PBL), is reported to produce patterned self-assembled monolayers (SAM) on solid substrates featuring two or three different chemical functionalities. For the pattern generation we use the phase separation of two immiscible polymers in a blend solution during a spin-coating process. By controlling the spin-coating parameters and conditions, including the ambient atmosphere (humidity), the molar mass of the polystyrene (PS) and poly(methyl methacrylate) (PMMA), and the mass ratio between the two polymers in the blend solution, the formation of a purely lateral morphology (PS islands standing on the substrate while isolated in the PMMA matrix) can be reproducibly induced. Either of the formed phases (PS or PMMA) can be selectively dissolved afterwards, and the remaining phase can be used as a lift-off mask for the formation of a nanopatterned functional silane monolayer. This “monolayer copy” of the polymer phase morphology has a topographic contrast of about 1.3 nm. A demonstration of tuning of the PS island diameter is given by changing the molar mass of PS. Moreover, polymer blend lithography can provide the possibility of fabricating a surface with three different chemical components: This is demonstrated by inducing breath figures (evaporated condensed entity) at higher humidity during the spin-coating process. Here we demonstrate the formation of a lateral pattern consisting of regions covered with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) and (3-aminopropyl)triethoxysilane (APTES), and at the same time featuring regions of bare SiOx. The patterning process could be applied even on meter-sized substrates with various functional SAM molecules, making this process suitable for the rapid preparation of quasi two-dimensional nanopatterned functional substrates, e.g., for the template-controlled growth of ZnO nanostructures [1].

SE analyses were performed for HKUST-1 and ITO thin films on a Woollam M-44 ellipsometer at a fixed incidence angle of 75° on silicon wafers as substrates, in the range 400-750 nm, see Figure S1a. Modeling, fitting, and regression of the ellipsometric data were performed using the VASE software provided by the manufacturer. For the numerical calculations and PBG simulations the program WINCPC was used based on the experimental nk.-files from the Woollam M-44 ellipsometer.

Superhydrophobicity is a physical feature of surfaces occurring in many organisms and has been applied (e.g. lotus effect) in bionic technical applications. Some aquatic species are able to maintain persistent air layers under water ( Salvinia effect) and thus become increasingly interesting for drag reduction and other ‘bioinspired’ applications. However, another feature of superhydrophobic surfaces, i.e. the adsorption (not absorption) and subsequent superficial transportation and desorption capability for oil, has been neglected. Intense research is currently being carried out on oil-absorbing bulk materials like sponges, focusing on oleophilic surfaces and meshes to build membranes for oil–water separation. This requires an active pumping of oil–water mixtures onto or through the surface. Here, we present a novel passive, self-driven technology to remove oil from water surfaces. The oil is adsorbed onto a superhydrophobic material (e.g. textiles) and transported on its surface. Vertical and horizontal transportation is possible above or below the oil-contaminated water surface. The transfer in a bioinspired novel bionic oil adsorber is described. The oil is transported into a container and thus removed from the surface. Prototypes have proven to be an efficient and environmentally friendly technology to clean oil spills from water without chemicals or external energy supply. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 3)’.