Superhydrophobicity-memory surfaces prepared by a femtosecond laser

Fabrication of Chalcogenide Glass Based Hexagonal Gapless Microlens Arrays via Combining Femtosecond Laser Assist Chemical Etching and Precision Glass Molding Processes

“…The mold can be used thousands of times over without mold repair, so the fabrication of ChG MLA starts from a hard and high-temperature-resistant concave mold, which is made by a highly efficient FLACE technique on a BK7 optical glass substrate. Femtosecond laser pulses (Libra-usp-he, Coherent) [42][43][44], with a central wavelength of 800 nm, pulse duration of 50 fs, repetition rate of 1 kHz and laser power of 5 mW, were used and focused by an objective lens, which had a numerical aperture of 0.5. The high peak intensity of moderately and tightly focused femtosecond laser pulses made this possible through nonlinear multiphoton, avalanche and Coulomb explosions producing permanent structural modifications within a couple of picoseconds.…”

Relationship and Interconversion Between Superhydrophilicity, Underwater Superoleophilicity, Underwater Superaerophilicity, Superhydrophobicity, Underwater Superoleophobicity, and Underwater Superaerophobicity: A Mini-Review

“…Superwettability can be designed by combining proper surface microstructures and chemistry (Yong et al, 2013a , 2017c ; Bellanger et al, 2014 ; Jiang et al, 2015 ; Wen et al, 2015 ; Su et al, 2016 ; Bai et al, 2020 ). Al is a typical hydrophilic substrate.…”

“…The relationship between these different superwettabilities is summarized in Figure 2 (Yong et al, 2017b ). The rough surface microstructure can amplify the natural wettability of a substrate (Yong et al, 2013a ; Bellanger et al, 2014 ; Jiang et al, 2015 ; Wen et al, 2015 ; Su et al, 2016 ; Bai et al, 2020 ). The intrinsic hydrophilicity of a substrate can be enhanced to extreme state (i.e., superhydrophilicity) by surface microstructure; that is, the synergistic effect of the rough microstructure and high-surface-energy chemical composition produces a superhydrophilic surface ( Figure 2A ).…”

“…For example, lotus leaf has the self-cleaning function (Barthlott and Neinhuis, 1997 ), water strider can walk on water surface (Gao and Jiang, 2004 ), the butterfly can shake off raindrops and fly in the rain (Zheng et al, 2007 ), the eyes of mosquito can repel fog (Gao et al, 2007 ), the fish scale cannot be polluted by oil in water (Liu et al, 2009 ; Yong et al, 2018b ), and desert beetle, cacti, and spider silk have the capacity of harvesting water in dry air (Parker and Lawrence, 2001 ; Zheng et al, 2010 ; Ju et al, 2012 ). It is demonstrated that the surface wettability is primarily determined by the surface composition and the surface morphology of a solid substrate (Yong et al, 2013a ; Bellanger et al, 2014 ; Jiang et al, 2015 ; Wen et al, 2015 ; Su et al, 2016 ; Bai et al, 2020 ). The study related to the surface wettability becomes a current research focus.…”

Mini-Review on Bioinspired Superwetting Microlens Array and Compound Eye

“…Raindrops or dewdrops have a sphere shape on the lotus leaf with the water contact angle (CA) above 150° (inset of Figure 1C ) and can easily roll away. Such superhydrophobicity is attributed to the combination of the hierarchical surface microstructures and the low-surface-energy chemical composition of the lotus leaf (Bellanger et al, 2014 ; Jiang et al, 2015 ; Wen et al, 2015 ; Su et al, 2016 ; Yong et al, 2017b , c , 2018b ; Bai et al, 2020 ). The scanning electronic microscopy (SEM) image reveals that plenty of papilla structures with a diameter of about 5 ~ 9 μm randomly distribute on the lotus leaf surface ( Figure 1C ; Yong et al, 2017a ).…”