Superhydrophobic Nanocoatings Fabricated by Materials with Low Young's Contact Angle

To achieve superhydrophobicity with an apparent contact angle (θ*) greater than 150° on rough surfaces, materials with a high Young's contact angle (θ_Y > 90°) are commonly utilized. However, achieving superhydrophobicity with θ_Y < 90° materials without specific auxiliary designs faces unknown challenges. Here, we develop a novel superhydrophobic nanocoating with θ* of ∼155° sprayed by an ethanol suspension only composed of bisphenol A epoxy resin (EPA) with a low θ_Y of ∼70° and hydrophilic SiO₂ nanoparticles. Additionally, we also show more superhydrophobic nanocoatings created by low θ_Y resins that even down to 58°. This superhydrophobicity results from sustained three-dimensional hydrogen bonding equilibrium on the droplet surface postcontact with the rough surface, despite low θ_Y. We also constructed a wetting transition model to quantify the impact of surface energy on the stability of droplet surface structures and revealed how the concentration of EPA can regulate the wetting behavior of the coating.