Fig. 1. Overview of the multi-strategy design and strengthening approaches for constructing robust superhydrophobic materials.

Fig. 2. Typical wetting behavior of droplets on a solid substrate: (a) Young's model, (b) Wenzel model, (c) Cassie model.

Fig. 3. (a) Schematic and SEM images of the synthesis of graphene-PDA-SiO2 composite particles. Reproduced with the permission from Ref. [65] and copyright ? 2019 Elsevier. (b) Schematic illustration of the concept for strengthening the surface microstructures through wearing a layer of rigid AP. SEM images of the surface without AP coating and with AP coating before and after the sand-abrasion, respectively. Reproduced with the permission from Ref. [90] and copyright ? 2019 Elsevier. (c) Schematic and SEM images of the armor-decorated superhydrophobic surfaces. Reproduced with the permission from Ref. [73] and copyright ? 2020 Nature Publishing Group. (d) Schematic illustration of the bionic layered diamond coatings preparation using HFCVD and self-assembly seeding and corresponding the SEM surface and cross-sectional images. Reproduced with the permission from Ref. [39] and copyright ? 2020 American Chemical Society.

Fig. 4. (a) Schematic illustrations of the gelation reaction of the (1) 5Acl and BPEI in ethanol, (2) reaction principle of NCs, and (3) NCs bulk after hydrophobic modification. Reproduced with the permission from Ref. [80] and copyright ? 2020 Elsevier. (b) Schematic diagrams of the preparation of lightweight water-repellent foam materials, corresponding SEM images, and PDMS cross-linking process. Photographs of the original MFPS and superhydrophobic block material in water. Reproduced with the permission from Ref. [69] and copyright ? 2020 Elsevier. (c) (1) Laser microscopy images and (2) wettability of elastic needle-like frameworks in different weight fractions of ZnO-tetrapod. Cross-sectional SEM image of an elastic needle-like framework coated on a polyethylene terephthalate substrate (3). Reproduced with permission from Ref. [106] and copyright ? 2019 American Chemical Society. (d) SEM and cross-sectional images of the TSCM: (1) Surface, (2) Bulk-1, and (3) Bulk-2 before and after sandpaper-abrasion. Reproduced with the permission from Ref. [107] and copyright ? 2020 Elsevier.

Fig. 5. (a) Preparation and characterization of the superhydrophobic coating via stoichiometric silanization. Reproduced with the permission from Ref. [119] and copyright ? 2021 Nature Publishing Group. (b) Schematic representation of the in-situ deposition of a growing polymeric nanocomplexes by 1, 4-conjugate addition reaction and post-modifications of the dipping with alkylamine. Reproduced with the permission from Ref. [83] and copyright ? 2019 American Chemical Society. (c) Schematic illustration of the synthesis of SiO2-core/PFA-shell NPs. The orange-colored lines indicate PFA. Reproduced with the permission from Ref. [120] and copyright ? 2018 Royal Society of Chemistry. (d) Schematic illustration of the fabrication of the superhydrophobic coating using the “photo polymerization + hydrolytic polycondensation” strategy. Reproduced with the permission from Ref. [76] and copyright ? 2019 American Chemical Society. (e) Schematic illustration of the fabrication of a superhydrophobic metal mesh using the chelating properties of PA on metal ions. Reproduced with the permission from Ref. [118] and copyright ? 2019 American Chemical Society.

Fig. 6. Main types of organic-inorganic hybridization of the (a) substrate + organic components + inorganic components, (b) substrate + organic components-inorganic components, (c) substrate + organic components + organic components-inorganic components, and (d) substrate + organic components + inorganic components + organic components.

Fig. 7. (a) Synthetic route of PFEP via the thiol-ene reaction. Reproduced with the permission from Ref. [165] and copyright ? 2021 American Chemical Society. (b) Synthetic route of FPU via the thiol-ene reaction. Reproduced with the permission from Ref. [72] and copyright ? 2020 Elsevier. (c) Schematic structure of typical silicone-acrylic copolymer. Reproduced with permission from Ref. [168] and copyright ? 2017 Royal Society of Chemistry. (d) Chemical structure of (1) EP, (2) curing agent, and (3) amino-functionalized polysiloxane. Reproduced with the permission from Ref. [166] and copyright ? 2020 Elsevier. (e) Chemical structure of FEVE.

Fig. 8. (a) Schematic illustration of the multi-fluorination strategy for the all-organic nanocomposite coating using fluoropolymer-grafted EP and PTFE particles. Reproduced with the permission from Ref. [51] and copyright ? 2018 Nature Publishing Group. (b) Synthesis route to the PUF-FC coating. Reproduced with the permission from Ref. [173] and copyright ? 2017 Royal Society of Chemistry. (c) Schematic illustration and SEM images of the superhydrophobic coatings made from biocompatible PDMS and carnauba wax. Reproduced with the permission from Ref. [142] and copyright ? 2019 Elsevier. (d) Schematic illustration of the principle of AACVD operation. WCA, SEM, and cross-sectional images of EP/PDMS coatings fabricated at 350 °C. Reproduced with the permission from Ref. [174,175] and copyright ? 2017 American Chemical Society, and copyright ? 2019 Royal Society of Chemistry.

Fig. 9. (a) TiO2 NPs and an AP adhesive form a robust superhydrophobic coating through cross-linking. Reproduced with the permission from Ref. [177] and copyright ? 2017 American Chemical Society. (b) Schematic illustration of the preparation and molecular interaction of the superhydrophobic coating using AP for multi-interfacial-strengthening. Reproduced with the permission from Ref. [79] and copyright ? 2020 American Chemical Society. (c) Schematic illustration of the preparation of a particle-free doped AP-based robust superhydrophobic coating. Reproduced with the permission from Ref. [179] and copyright ? 2021 American Chemical Society. (d) Schematic illustration of the fabrication of superhydrophobic fabrics using the synergistic effect of inorganic and organic adhesives. Reproduced with the permission from Ref. [180] and copyright ? 2020 Elsevier. (e) Schematic illustration of the preparation of superhydrophobic coating using sodium silicate. Reproduced with the permission from Ref. [181] and copyright ? 2021 Elsevier. (f) Optical, schematic, and SEM images of the different color superhydrophobic coatings based on silicate cement strengthening. Reproduced with the permission from Ref. [183] and copyright ? 2020 Elsevier.

Fig. 10. (a) Schematic illustration for fabrication of the self-healing superhydrophobic coating-based hollow mesoporous SiO2 NPs. Reproduced with the permission from Ref. [155] and copyright ? 2016 American Chemical Society. (b) Schematic process of the synthesis of the PDMS-loaded mesoporous PDA microspheres. Reproduced with the permission from Ref. [187] and copyright ? 2020 Elsevier. (c) Schematic illustration of the preparation of a UV and NIR dual-responsive self-healing superhydrophobic coating. Reproduced with the permission from Ref. [186] and copyright ? 2020 American Chemical Society. (d) Synthesis of pH-responsive microcapsules. Reproduced with the permission from Ref. [189] and copyright ? 2020 American Chemical Society. (e) Schematic showing the self-healing mechanism of a room temperature repairable superhydrophobic coating. Reproduced with the permission from Ref. [191] and copyright ? 2020 Elsevier. (f) Wax storage in PDMS matrix-like cuticle. Behavior of self-growth of waxy structures on the wax gel surface after physical damage. Reproduced with the permission from Ref. [192] and copyright ? 2021 Royal Society of Chemistry.

Fig. 11. (a) SEM images and corresponding WCA change of the SMEP surface viewed at 45° of (1) the original state, (2) after pressing, and (3) after further heating. Reproduced with the permission from Ref. [47] and copyright ? 2016 Wiley. (b) SEM and wettability change images during compression/recovery of the (1) original, (2) collapsed, and (3) recovered SMPU arrays. Reproduced with the permission from Ref. [197] and copyright ? 2019 Elsevier. (c) SEM images of the superhydrophobic surfaces: (1) original, (2) collapsed, (4) scratched, and (3 and 5) healed surfaces. The inset shows the wettability change on the corresponding surface. Reproduced with the permission from ref. [48] and copyright ? 2017 Royal Society of Chemistry. (d) Schematic structure and damage-healing process of the superhydrophobic coating relying on the hydrogen bonds and metal ligand-based supramolecular silicone polymer. Reproduced with the permission from Ref. [201] and copyright ? 2020 Elsevier. (e) SEM and wettability change images of the conductive superhydrophobic coating with a cut≈ 650 μm wide before and after being healed with an applied voltage of 4 V. Reproduced with the permission from Ref. [203] and copyright ? 2016 Wiley.

Fig. 12. (a) Schematic and SEM images of fabrication of stretchable superhydrophobic surfaces with micro-pyramid arrays of tertiary rough wrinkled structures in the left picture. Tensile-release and linear wear test vs wettability curves in the right picture. Reproduced with the permission from Ref. [53] and copyright ? 2021 Wiley. (b) Schematic and SEM images of the flexible superhydrophobic film preparation using the magnetic field-assisted method in the left picture. Optical of droplets images and wettability variation at stretching from 0% to 125%, tensile-release at periodical stretching of 100%, droplet bounce at periodical stretching of 125%, as well as flexibility and droplet repellency on the umbrella surface of the flexible superhydrophobic film in the right picture. Reproduced with the permission from Ref. [58] and copyright ? 2020 Wiley. (c) Schematic illustration of the hierarchical structure with the partially-embedded graphene in the left picture. Optical of water droplets images and wettability variation at the stretching of 0%, 200%, and 400%, tensile-release at the stretching of 300% in the right picture. Reproduced with the permission from Ref. [209] and copyright ? 2018 Royal Society of Chemistry. (d) Fabrication for highly stretchable and conductive superhydrophobic coating on the natural rubber in the left picture. SEM and wetting change images of the superhydrophobic coatings at the stretching of 0%, and 900% in the right picture. Reproduced with the permission from Ref. [211] and copyright ? 2018 American Chemical Society.

Fig. 13. (a) Schematic illustration of the preparation of the superhydrophobic surfaces using sol-gel composite double-scale SiO2 NPs on the different substrates. Reproduced with the permission from Ref. [35] and copyright ? 2017 American Chemical Society. (b) Wettability changes of P25-P2@Glass surface after UV irradiation and restoration. Glass transmittance as different treatment conditions and Optical pictures of water droplets on different coated substrates. Reproduced with the permission from Ref. [221] and copyright ? 2020 Elsevier. (c) Synthesis route of PDMS-PBA, wettability changes of the N-Boroxine-PDMS film before and after healing, and water rebound phenomenon. Reproduced with the permission from Ref. [220] and copyright ? 2020 Elsevier. (d) Schematic of the fabrication of superhydrophobic surface using superhydrophobic film sedimentation method. Reproduced with the permission from Ref. [216] and copyright ? 2020 Elsevier. (e) Schematic of the fabrication of superhydrophobic surface using mesoporous SiO2 nanosheets and hollow SiO2 nanospheres. Reproduced with permission from Ref. [222] and copyright ? 2016 Elsevier. (f) Schematic and corresponding SEM images for preparation of the transparent superhydrophobic surface using decompose carbon materials by high-temperature calcination. Reproduced with the permission from Ref. [223] and copyright ? 2017 Elsevier.

Fig. 14. (a) Combustion of the decorative alginate fabric flower, after it was ignited for 5 s. Combustion of a decorative dyed PET fabric flower treated with hexadecyl polysiloxane after it was ignited for 2 s. Reproduced with the permission from Ref. [232] and copyright ? 2021 Springer. (b) Schematic illustration for the preparation of flame-retardant rigid PU foam. The surface temperature determined by the IR camera for untreated PU and FRPU-60/40-600 μm after being ignited for 15 min above an alcohol lamp. Reproduced with the permission from Ref. [231] and copyright ? 2021 American Chemical Society. (c) Schematic of polyphenol-modified silk fabric in the left picture. Images of the specimens after the vertical flame test of the burned (1) silk fabrics, (2) dopamine-modified silk fabric, (3) dopamine-Fe-modified silk fabric, and (4) dopamine-Fe-modified silk fabric after 210 min accelerated washing in the right picture. Reproduced with the permission from Ref. [117] and copyright ? 2019 Elsevier. (d) Schematic preparation of the anti-scald superhydrophobic fabric in the left picture. Schematic illustration of the boiling water scald models on rat dorsum covered by the anti-scald superhydrophobic fabric in the right picture. Reproduced the with permission from Ref. [85] and copyright ? 2020 Elsevier.

Fig. 15. (a) Robustness testing, diagram of the preparation of the PDMS/SiO2 superhydrophobic coating, dynamic polarization, and EIS curves of Mg alloy and PDMS/SiO2 composite coatings. Reproduced with the permission from Ref. [237] and copyright ? 2018 Elsevier. (b) Schematic illustration of F-SiO2/HNTs composite, PANI/HNTs composite, and superhydrophobic coating. Dynamic polarization curves for uncoated and coated aluminum plates after 1 h immersion in 3.5 wt.% NaCl solution. Reproduced with the permission from Ref. [170] and copyright ? 2019 Elsevier. (c) Fabrication process of EP coating, superhydrophobic ZIF-8/POTS coating, and ZIF-8/POTS/EP coating. Bode and phase angle plots of bare Q235 steel and various coatings. Reproduced with the permission from Ref. [156] and copyright ? 2020 Elsevier. (d) Schematic illustration of self-healing and anti-corrosion mechanisms of the SHEP coating, PF-POS@silica coating, and SHEP/PF-POS@silica coating. Bode and phase angle plots of the Mg alloy and coated Mg alloy. Reproduced with the permission from Ref. [240] and copyright ? 2020 Elsevier.