Self-Adapting Wettability of ReS2 under a Constant Stimulus.

Responsive materials (RMs) are attracting intense interest for their critical roles in intelligent designs. So far, only by means of applying complicated and multiple stimuli can physical properties of the solid surface realize a transition, limiting their practical applications. Here, the smart self-adapting wettability (SAW) of ReS2 under sustaining light irradiation, which breaks the stereotype that a single stimulus leads to a monotonic change in properties or structures, is presented. The additional valence electron and defects ensure ReS2 has a stronger gas adsorption and better hydrolysis capability. Combining theoretical calculations and experimental results, its mechanism, including three stages, namely, hydroxyl substitution, formation of hydrogen bonds, and water desorption, is confirmed. Notably, other transition metal dichalcogenides covering MoS2 and WS2 exhibit a similar automatic transition of hydrophobic-hydrophilic-hydrophobic state. This unique SAW provides a brand-new insight to broaden the applications of RMs, which will undoubtedly pave a novel way in RMs design and further devices optimization.