Fabrication of superhydrophobic silicone rubber by ArF-excimer-laser-induced microstructuring for repelling water in water

Abstract

Microswellings of 1 µm height, 1.5 µm diameter, and regular intervals of 2.5 µm on a silicone rubber surface were fabricated using a 193 nm ArF excimer laser. The laser was focused on silicone by each microsphere made of silica glass of 2.5 µm diameter; these microspheres covered the entire surface of the silicone. The surface underneath each microsphere selectively swelled owing to the photodissociation of the Si–O bonds of silicone. The contact angle of water was measured to be approximately 155°, indicating a clear superhydrophobicity. The samples successfully repelled water in water to form an air gap layer between silicone and water.

Formation of textured Al thin film on periodic microswelling structure fabricated on silicone rubber surface to realize superhydrophobicity

“…Moreover, this swelling phenomenon was shown to be induced even with an ArF excimer laser (wavelength: 193 nm), as distinct from modification into SiO 2 . Thus, we confirmed that silicone rubber surface can be provided with superhydrophobicity through local irradiation using an ArF excimer laser to perform depolymerization due to photodissociation of main chain structure, and to create a periodic microswelling structure, without modification into SiO 2 …”

“…19 Thus, we confirmed that silicone rubber surface can be provided with superhydrophobicity through local irradiation using an ArF excimer laser to perform depolymerization due to photodissociation of main chain structure, and to create a periodic microswelling structure, without modification into SiO 2 . [20][21][22] In this paper, we continue the previous research toward further improvement of superhydrophobicity of silicone rubber surface with a periodic microswelling structure; particularly, we show that when Al thin film is deposited, the surface does not become flat, but a fine texture appears. As a result, contact angle of the sample surface with water increases due to Al film deposition.…”

“…The irradiation was performed in Ar gas atmosphere. After the irradiation, the samples were immersed in 1 wt% HF aqueous solution for 90 s, and then the microspheres were removed by ultrasonic cleansing in ethanol for 10 min …”

“…After the irradiation, the samples were immersed in 1 wt% HF aqueous solution for 90 s, and then the microspheres were removed by ultrasonic cleansing in ethanol for 10 min. 20 The surface of silicone resin with thus produced periodic microswelling structure was put to vacuum deposition using aluminum wire (purity: 99.99%) to form Al thin film. The film thickness was made 70 nm and 100 nm.…”

Micro/nano-suction cup structure of silicone rubber fabricated by ArF excimer laser

“…Recently, when the ArF excimer laser irradiated a silicone rubber, instead of F 2 laser, the photochemical swelling phenomenon which is due to the photodissociation of Si-O bonds of silicone rubber was found on the surface [19,20]. Microspheres made of SiO 2 in micron size were used for fabricating the periodic microswelling structure of silicone rubber, resulting in high superhydrophobic properties [21,22].…”