Two types of superhydrophobic surfaces which show lotus and petal effects were induced on photochromic diarylethene microcrystalline surfaces by UV and visible light irradiation and temperature control. On the surfaces showing the lotus effect, a low-adhesion superhydrophobic property is attributed to the surface structure being covered with densely standing needle-shaped crystals of the closed-ring isomer. On surfaces showing the petal effect, a high-adhesion superhydrophobic surface consists of fine needle-shaped crystals with high density together with a few rod-shaped crystals, where an invasion phenomenon occurs between these rod-shaped crystals. Furthermore, the different superhydrophobic properties of the surfaces are theoretically explained using multipillar surface models.

We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light.

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DSC curves measured for a mixture of 4o and 4c, absorption spectral changes of 4o, thermal stability of 4c, force curves obtained by SPM on single crystalline surfaces and relation between temperatures and slope of force curves By alternate irradiation with UV and visible lights, reversible topographical changes were observed on the microcrystalline surfaces of diarylethene derivatives above the glass transition temperatures (T g ) of their open-ring isomers. For the photogenerated closed-ring isomers, the crystal growth proceeded at the surface softened by molecular movement. This is self-aggregation of the closed-ring isomers. The photogenerated surface topographies appear depending on their crystal habits of the closed-ring isomers. Reflecting the properties (crystal habits) of diarylethene derivatives, we obtained cubic, needle, and plate-shaped crystals of the closed-ring isomers on the microcrystalline surfaces of the open-ring isomers by the irradiation with UV light. Even a derivative having one isopropyl group at a reactive carbon atom, whose closed-ring isomer is thermally unstable, showed the photoinduced topographical changes, because the T g of open-ring isomer is around ambient temperatures. Scheme 1. Molecular structures of open-(o) and closed-ring (c) isomers of the diarylethenes 1, 2, 3, and 4.

A diarylethene with a malachite green moiety was synthesized, and it showed multicolor states by photochromic and halochromic reactions.