Superhydrophilic-superhydrophobic patterned surfaces on glass substrate for water harvesting

Directional water harvesting is a special ability of flora and fauna in nature. Wettability-patterned surfaces inspired by natural structures have been extensively researched and could be a great potential avenue for easing water shortage. However, preparation strategies for these nature-inspired cases, including UV irradiation with mask technology, femtosecond laser direct writing and chemical treatment, are time-consuming, cost-ineffective and environmentally unfriendly. In this paper, robust and durable superhydrophobic (SHB) glass substrate was prepared by using laser-induced backward transfer technique and fluoroalkylsilane modification. Then wedge-shaped superhydrophilic (SHL) patterns on the SHB surfaces were rapidly constructed by inexpensive and commercially available fibre laser ablation for fog harvesting. This facile, cost-effective and non-corrosive preparation method described herein could be an alternative way to construct SHL-SHB patterns on glass substrate, which could be used for microfluidic devices, droplet manipulation and cell screening.