Robust Superhydrophobic Coatings Enabled by Carbonation-Induced In Situ Hydrophobization

Conventional carbonation of calcium silicates locks away CO₂ yet leaves behind hydrophilic, brittle surfaces. Here, we transform this limitation into an opportunity by developing a hydrophobization-assisted carbonation strategy that simultaneously fixes CO₂ and constructs a durable superhydrophobic coating. The introduction of fluorinated silane (PFOTES) modifies the local carbonation environment and promotes the formation of abundant micro-scale CaCO₃ features integrated with low-surface-energy components, leading to a hierarchical mineralized surface rather than a superficial deposited layer. The optimized coating achieves a CO₂ uptake of 9.92 wt% as quantified by TG/DTG analysis, together with a high-water contact angle of ∼158.9° and a ∼35.9% increase in pull-off adhesion strength compared with the pristine coating. More importantly, the superhydrophobic state remains stable under abrasion, particle impact, UV irradiation, and prolonged exposure to water, salt, and alkaline environments. Structural characterization further indicates that PFOTES modification alters the surface morphology and roughness evolution during carbonation, contributing to the development of a more stable non-wetting state. This work demonstrates a route for coupling carbonation-driven inorganic growth with surface functionalization, providing new insights into durable superhydrophobic coatings derived from calcium silicate systems and carbonation-enabled surface engineering.