Phototunable Diarylethene Microcrystalline Surfaces: Lotus and Petal Effects upon Wetting

Uchida, Kôji; Nishikawa, Naoki; Izumi, Norikazu; Yamazoe, Seiji; Mayama, Hiroyuki; Kojima, Yoshitaka; Yokojima, Satoshi; Nakamura, Shinichiro; Tsujii, Kaoru; Irie, Masahiro

doi:10.1002/ange.201000793

Cited by 85 publications

(15 citation statements)

References 30 publications

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“…[18][19][20] The change in the surface topology by the crystal growth of a photochromic diarylethene has recently been reported. [21,22] In this case, the contact angle with water changed from 1208 to 1638 upon UV light irradiation because of the generation of the closed-ring isomer crystal of the fibrils on the crystal surface. The reversible changes in the contact angle were attributed to reversible changes in the surface roughness.…”

Section: Introductionmentioning

confidence: 95%

Control of Surface Wettability and Photomicropatterning with a Polymorphic Diarylethene Crystal upon Photoirradiation

Kitagawa

Yamashita

Kobatake

2011

Chemistry A European J

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A photochromic diarylethene crystal of 1,2-bis(2-methyl-6-nitro-1-benzothiophen-3-yl)perfluorocyclopentene (1 a) was found to undergo a thermodynamic phase transition at 180 °C to form a needle-like crystal, designated as 1 a-γ. The phase transition involves melting of the initial α-crystal and growth of the γ-crystal. The phase transition temperature decreased with the presence of the closed-ring isomer (1 b) in the crystal because of the decrease in the melting temperature. Upon irradiation with ultraviolet (UV) light, compound 1 a in the α-crystal was converted into 1 b to an extent of 20 %. Consequently, the α-crystal containing 20 % of 1 b underwent the phase transition accompanied by melting of the crystal and growth of the γ-crystal even at 170 °C. Photomicropatterning by the phase transition upon irradiation with UV light using a photomask, followed by heating at 170 °C, was successfully accomplished with a resolution in the microcrystalline pattern of about 20 μm. The contact angle with water on the γ-microcrystalline phase on a glass substrate was larger than that on the α-microcrystalline phase by 20°. This can be ascribed to a difference in the roughness of the surface. Furthermore, the γ-microcrystal was also found to be formed upon heating an amorphous film of 1 a in poly(methyl methacrylate) for 2 min at 130 °C. The crystallized area exhibited a higher water contact angle than the amorphous area. Upon irradiation of the amorphous film with UV light, such crystallization did not take place because of the impurity effect of 1 b in 1 a. Photomicropatterning by the crystallization in the polymer showed a pattern with a higher resolution of about 4 μm, which was much better than that of the neat crystal. This photopatterning process represents a useful tool for controlling the surface wettability in relevant applications.

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Section: Introductionmentioning

confidence: 95%

Control of Surface Wettability and Photomicropatterning with a Polymorphic Diarylethene Crystal upon Photoirradiation

Kitagawa

Yamashita

Kobatake

2011

Chemistry A European J

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“…Previously, we have reported photoinduced reversible wettability changes on the microcrystalline surface of a diarylethene, 1,2‐bis(2‐methoxy‐5‐trimethylsilylthien‐3‐yl)perfluorocyclopentene ( 1o in Scheme ), not by surface polarity changes but by topographical changes on the surface 16a. d Compound 1o is a photochromic molecule that is converted into the blue‐colored isomer 1c upon irradiation with UV light and reverts to the original 1o by irradiation with visible light. The crystal shapes of 1o and 1c are cubes and needles, respectively.…”

Section: Introductionmentioning

confidence: 99%

Photoinduced Reversible Topographical Changes on Diarylethene Microcrystalline Surfaces with Biomimetic Wetting Properties

Nishikawa

Uyama

Kamitanaka

et al. 2011

Chemistry An Asian Journal

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Reversible topographical changes were observed on a photochromic diarylethene microcrystalline film surface by alternate irradiation with UV and visible light. Two types of surfaces were prepared from this film: 1) Storage of the film at 30 °C for 24 hours in the dark after UV irradiation afforded a surface that was covered with needle-shaped crystals, whose diameter and length were approximately 1 μm and 10 μm, respectively, and showed a superhydrophobic lotus effect. 2) Storage of the film at 70 °C for 3 hours in the dark caused the needle-shaped crystals to be converted into larger rod-like crystals (5~8 μm wide and 20~30 μm long) by Ostwald ripening and a disappearance of the lotus effect. The obtained activation energy of the formation of the needle- and rod-shaped crystals was 143 and 162 kJ mol(-1), respectively. Subsequent UV irradiation to the surface, which was followed by storage at 50 °C for 1 hour in the dark, gave a doubly rough structure; small needle-shaped crystals were formed between the larger rod-shaped crystals. The surface showed both superhydrophobic properties and the pinned effect of the water droplet: the petal effect. Fractal analysis of both surfaces were carried out using a box-counting method, and the lotus effect was observed in the presence of smaller-sized crystals, whilst the petal effect was observed with larger sized crystals (ca. 100 μm). We demonstrated that the hydrophobic property was controlled by the distribution in crystal size of the closed-ring isomer of the diarylethene. Visible-light irradiation of both rough surfaces afforded surfaces with cubic-shaped micro-crystals of the open-ring isomer.

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“…To fabricate the rough surface with needle shaped crystals of 1 c , the storage temperature was elevated and CA increased rapidly. Consequently, a superhydrophobic surface with CA>150° was prepared within 30 min and 1 h for 70 °C and 50 °C, respectively . By continuous storage at the elevated temperatures, CA gradually decreased and superhydrophobicity was lost.…”

Section: Photoinduced Topographical Changes For Biomimetic Functionsmentioning

confidence: 99%

“…We prepared a composite surface mimicking rose petals by the following procedure as shown in Figure . After UV irradiation, heating at 30 °C for 24 h in the dark made the lotus surface (c) via the UV‐irradiated surface of the state in (b).…”

Section: Photoinduced Topographical Changes To Form Surfaces With Biomentioning

confidence: 99%

Photochromic Crystalline Systems Mimicking Bio‐Functions

Uchida

Nishimura

Hatano

et al. 2018

Chemistry A European J

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Photoresponsive crystalline systems mimicking bio-functions are prepared using photochromic diarylethenes. Upon UV irradiation of the diarylethene crystal, the photogenerated closed-ring isomers self-aggregate to form needle-shaped crystals on the surface. The rough surface shows the superhydrophobic lotus effect. In addition, the rose-petal effects of wetting, the anti-reflective moth-eye effect, and a double-roughness structure mimicking the surface of a lotus leaf are observed by controlling the heating procedures, UV irradiation processes, and molecular structural modification. By changing the molecular structure, a superhydrophilic surface mimicking a snail shell can be generated. We also find the crystal of a diarylethene derivative that shows a photosalient effect. The effect is observed partly due to the hollow structure of the crystal. It is demonstrated that a photo-response similar to the response of impatiens plant to stimulation is observed by packing small beads in the hollow. These photoresponsive functions are unique, and they demonstrate a macroscopic response by means of microscopic molecular movement induced by light. In the future, such a molecular assembly system will be a promising candidate for fabricating photoresponsive architectures and soft robots.

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Phototunable Diarylethene Microcrystalline Surfaces: Lotus and Petal Effects upon Wetting

Cited by 85 publications

References 30 publications

Control of Surface Wettability and Photomicropatterning with a Polymorphic Diarylethene Crystal upon Photoirradiation

Control of Surface Wettability and Photomicropatterning with a Polymorphic Diarylethene Crystal upon Photoirradiation

Photoinduced Reversible Topographical Changes on Diarylethene Microcrystalline Surfaces with Biomimetic Wetting Properties

Photochromic Crystalline Systems Mimicking Bio‐Functions

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