Aqueous Fabrication of Recyclable and Color-Adjustable Superhydrophobic Pigments Based on NiFe-Layered Double Hydroxide Nanostructures for Coating Applications

Endowing inorganic mineral pigments with superhydrophobicity greatly improves their stability for applications in architectural coatings and artworks. However, it remains challenging in the preparation of superhydrophobic pigments, such as complicated processes, high-cost, use of organic solvents, and fluorine-containing materials. Here, we report superhydrophobic colorful inorganic pigments with color gradient that were synthesized under atmospheric pressure and water-based conditions through a one-pot method, which is simple, fluorine-free, low-cost, and mild. The as-prepared pigments were assembled with nanostructures (nano spikes or nanoparticles), which exhibit the micro-/nanoscale hierarchical structures desired for superhydrophobicity. By precisely adjusting the ratio of Ni2+ and Fe3+, the in situ color matching and hydrophobic modification by dodecylbenzene sulfonic acid of micro–nano pigments were simultaneously realized. The superhydrophobic pigments retained their functions in a variety of harsh environments (e.g., corrosive solution, ultraviolet irradiation, high temperature, and so on) and were available in various coating techniques to construct superhydrophobic coatings, superhydrophobic paintings, and superhydrophobic tapes with colorfulness. Additionally, the waste liquid generated in the preparation process could be completely recycled and reused for pigment preparation, which is highly environmental-friendly for saving raw materials and avoiding pollution discharge. These superhydrophobic pigments would have great potential for eco-friendly industrial production and application in architecture coating, artworks, and building decoration.