A review on 3D printing of bioinspired hydrophobic materials: oil-water separation, water harvesting, and diverse applications

Bioinspired nanosurfaces with hydrophobicity and multifunctionality have stimulated wide interests in both basic research of fundamental wetting theory and practical application arising from various intriguing phenomena in nature. 3D printing has become one of the most promising techniques for the manufacture of biomimetic materials with versatile applications because of the various advantages including easy accessibility and low cost. Here, a comprehensive review of recent progress on 3D-printed hydrophobic materials and their application was presented to summarize the achievement of the field and look forward to the future research perspective. First, classical models of hydrophobicity and theoretical progress related to the wetting phenomena are proposed. Moreover, diverse mechanism of 3D-printing techniques is systematically summarized following the classification of the methods to gain hydrophobicity in the 3D-printing process. Subsequently, bioinspired intriguing applications including drag reduction, water harvesting, oil-water separation, and 4D-printing are introduced from theory to practice. Finally, a general summary is drawn along with future guidelines for the fabrication of hydrophobic materials which fully utilize the advantage of 3D printing.Graphical abstractComprehensive review for hydrophobic 3D-printed material: theories, applications, and future prospects for oil-water separation, water harvesting, drag reduction, and 4D-printing.