Efficient water boiling evaporation via a laser-architected superhydrophilic, underwater superaerophobic, and high infrared emissivity interface

Abstract

Water boiling evaporation is crucial for diverse applications ranging from thermal management to power generation. However, current strategies for water boiling evaporation interfaces are restricted to complicated fabrication methods, single function, and low availability. Here, a superhydrophilic (a water contact angle of ∼ 0°), underwater superaerophobic (a bubble contact angle of ∼ 161.5°), and high infrared emissivity (up to 0.9) interface is fabricated via femtosecond laser direct writing technology. The extreme surface wettability and underwater superaerophobicity combined with its high infrared emissivity result in greatly enhanced water temperature ascending speeds and water boiling evaporation efficiency. At the optimum scanning speed, with a heater set at 190 °C and ∼ 0.2 mL volume water, the water on the laser-treated stainless steel surface exhibits the shortest time (∼20 s) required for water boiling evaporation, which is significantly shorter than that of on the pristine stainless steel surface (∼71 s). Moreover, the laser-treated surfaces demonstrate fast water boiling in a heating kettle and rapid water evaporation on an electrical heating element. The temperature of water in the laser-treated stainless steel cup rises faster than that in the pristine stainless steel cup, reaching boiling 1 min earlier and stabilizing ∼ 2 °C higher. Femtosecond laser treatment improves the highest water evaporation efficiency of the electrical heating rod by ∼ 49.1%. Understanding the design parameters for efficient water boiling evaporation using laser-treated surfaces can lead to the development of highly effective technology.