Facile Preparation of a Fluorine-Free, Robust, Superhydrophobic Coating through Dip Coating Combined with Non-Solvent Induced Phase Separation (Dip-Coating-NIPS) Method

Superhydrophobic surfaces based on non-fluorinated materials and facile fabrication techniques are of great practical value with respect to environmental friendliness and industrial applications. In this work, a fluorine-free, superhydrophobic coating with hierarchical surface structure and low surface energy is successfully fabricated on various substrates through a recently developed dip coating combined with non-solvent induced phase separation (dip-coating-NIPS) method. A bio-based polymer, poly(l-lactic acid), and commercially available hydrophobic SiO2 nanoparticles, are used. The fabricated coating exhibits superhydrophobicity, with a static water contact angle (WCA) of 155.7 degrees +/- 1.4 degrees and contact angle hysteresis (theta(Hys)) of 5.2 degrees +/- 0.4 degrees. The results from stability tests demonstrate excellent mechanical durability and chemical stability of the superhydrophobic coating. Finally, the fabricated coating is successfully applied in water-oil separation with superior efficiency. This simple, cost-effective, and time-efficient method may provide an effective way for the design of nonfluorine-based environmentally friendly membranes for separation applications.