A spontaneous water-detaching hydrophobic coating resistant to calendar aging based on non-equilibrium wetting

Abstract

Hydrophobic surfaces can spontaneously remove adhering water and dust due to their unique “lotus effect”, offering significant value in self-cleaning, anti-icing, drag reduction, and anti-contamination fields. However, compared to natural hydrophobic surfaces, artificially engineered counterparts often suffer from inherent limitations, among which the rapid degradation of hydrophobicity remains one of the most critical barriers to their widespread application. Moreover, the underlying mechanism governing this decay process is still not sufficiently clear. To address these challenges, we propose to divide wetting behavior into two categories: equilibrium wetting and non-equilibrium wetting. The proposal suggests that the accumulation of contaminants under non-equilibrium wetting conditions plays a pivotal role in the deterioration of surface hydrophobicity. Based on this insight, we develop a water-based coating which can generate a spontaneous water-detaching surface that is resistant to calendar aging and can maintain a durable hydrophobic effect under diverse outdoor climate conditions.