Micropatterned thin films have received increased interest in the past few years. Besides preparation by conventional lithography, self-assembly of materials around a template can be used for patterning. Recently a method that utilizes the condensation of micrometer-size water droplets on solutions of block copolymers was reported for the preparation of ordered micrometer-size honeycomb structures. Here we show that the formation of honeycomb-like porous films is a general method that can be used for patterning many materials, e.g., block copolymers, amphiphilic polyion complexes, organic/inorganic hybrids, and homopolymers, such as polystyrene. Stabilization of water droplets is indispensable for regular pattern formation.

This report describes the simple preparation of superhydrophobic and lipophobic surfaces by self-organization. Microporous polymer films of a fluorinated polymer with hexagonally arranged pores were prepared by casting from solution under humid conditions. Hexagonally packed water microdroplets were formed by evaporative cooling on the surface of the casting solution. After solvent evaporation, a honeycomb-patterned polymer film was formed with the water droplet array acting as a template; the water droplets themselves evaporated soon after the solvent. Two porous polymer layers were stacked vertically, separated by pillars at the hexagon vertexes. After peeling off the top layer using adhesive tape, a pincushion-like structure was obtained. Here, we show that superhydrophobic behavior was achieved, with the maximum contact angle, 170 degrees, observed using these pincushion structures. Theoretical calculations fit the experimental results well. The lipophobic properties of the films are also discussed.

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The sub-wavelength honeycomb-patterned films, which have optical transparency and superhydrophobicity, were fabricated by using condensed water droplets on the surface of a fluorinated polymer solution casting under humid conditions as the template.

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Regular polymer patterns are formed from casting a dilute polymer solution on a solid substrate. Dissipative structures, e.g., convection patterns, fingering instabilities, and so on, are formed in the evaporation process of casting polymer films. Controlled production and manufacturing of patterned polymer films can be achieved when the evaporating solution edge, especially the meniscus region on the casting substrate, is formed under controlled casting conditions. In this report, we describe a computer‐controlled apparatus which has two precisely manipulated sliding glass plates. A narrow, thin liquid film of polymer solution with a receding meniscus is continuously supplied from a small gap between two glass plates (one sliding and the other stationary), and a patterned polymer film is subsequently formed on the stationary substrate from the evaporating solution edge. Several types of polymer patterns from various polymers are reproducibly prepared by changing preparation conditions such as sliding speed and polymer concentration.

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Absorptionsspektren, sichtbar und ultraviolett / Biophysikalische Chemie / Doppelschicht-Membranen / Phasenum wandlungen / Zwischenmolekulare Wechselwirkungen Azobenzene-containing, single-chain ammonium amphiphiles in which the alkyl chain length in the tail and spacer portions was systematically varied were prepared, and their aggregation behavior in water was studied by electron microscopy, differential scanning calorimetry and absorption spectroscopy. These amphiphiles exist as molecular dispersions, hydrated microcrystals, micelles, or bilayers. The formation of stable bilayers was deduced on the basis of three criteria which include the spectral agreement between aqueous dispersions and the corresponding cast films. Stable bilayers were obtainable when the sum of tail and spacer is not smaller than C,4 to C16, and the tail is at least C,. Double-chain ammonium amphiphiles which possess an octadecyl chain in addition to the azobenzene-containing chain were prepared and shown to form stable bilayers. The absorption spectrum reflected the aggregate structure. In particular, the bilayer spectra were classified into four types: type A (,Imax ca. 300 nm) for the parallel chromophore orientation (H aggregate), type B (330-340 nm) for the dimeric chromophore, type C (ca. 355 nm) for the isolated chromophore, and type D (360 -390 nm) for the head-to-tail chromophore orientation (J-like aggregate). Liquid-crystalline bilayers gave type B spectra, while crystalline bilayers gave either of types A, B, and D, depending on the alkyl chain length. Finally, various examples of spectral control were discussed in relation to the Dresent results.