Research on superwetting surfaces/coatings that artificially mimic biological surfaces/systems has a long history, and still garners significant worldwide interest as it is expected to provide superior solutions to conventional engineering approaches that attempt to solve challenges facing mankind. To broaden the utility of these superwetting surfaces/coatings, there is a strong demand for these surfaces to exhibit multiple practical functionalities. Here, the progress being made in multifunctional surfaces with superwettability is explored. In each section, state‐of‐the‐art works are summarized and the concepts, materials, processes, and the effects of both physical (smooth or structured surfaces) and chemical (low or high surface energies) factors on the resulting surface are described. Finally, the outlook of this prospective research field is considered, and its future directions briefly discussed, with a focus on preserving longevity in both functionality and structural integrity to produce truly useful biomimetic surfaces/coatings.

Electrospun nanofiber mats have been patterned and used as stencils for high-fidelity screen printing using water-based inks.

Chemically and spatially micropatterned surfaces have been successfully prepared for a number of diverse applications, including water/fog harvesting, screen printing, microfluidics, and cell/protein assays. While there have been quite some reports on micropatterned surfaces, less is known about the factors that influence dynamic surface wettability. To that end, smooth checkerboard-like micropatterned hydrophobic/(super)hydrophilic surfaces (2, 5, 10, 20 μm pattern sizes) with regions of matching/mismatching contact angle hysteresis (CAH) were prepared on the basis of a simple chemisorption/photopatterning of monolayers. The effects of regional wettability/CAH and pattern size on the overall dynamic wettability were then examined by measuring the dynamic contact angles (CAs) and substrate tilt angles (θ T ) of water. It was found that the dynamic wettability on samples with matching regional CAH remained unchanged, even when using hydrophilic regions or changing the pattern size. In contrast, surfaces containing mismatching CAH regions pinned water droplets, leading to overall dynamic wetting properties markedly dependent on pattern size. In addition, the experimental data did not match values predicted by the Cassie equation because dynamic wetting behavior is dominated not by interfacial area but by the interactions of the liquid and solid at the three-phase contact line.

A highly cross-linked coating tends to have a high shear modulus and ice adhesion strength, while a lightly crosslinked rubber lacks wear resistance but sheds ice readily. This paper reports a polyurethane (PU) coating that is heavily crosslinked in the bulk but is lightly cross-linked near its surface (LICROS) for ice shedding. To achieve this, two methacrylate polyols (P1 and P2) are synthesized by free radical polymerization. Of the polyols, P1 is rich in cross-linkable 2-hydroxyethyl methacrylate (HEMA) units and P2 is rich in non-cross-linkable 2-ethylhexyl methacrylate (EHMA) units and also contains 4.1 mol % of 2-(perfluorohexyl)ethyl methacrylate (FC 6 -MA) units. Solvent evaporation from a solution mixture of P1, P2, and a hexamethylene diisocyanate trimer (HDIT) causes P2 to stratify to the coating's surface due to the low surface tension of FC 6 -MA. After thermal curing and lubrication with dibutyl phthalate (DBP), the resulting LICROS coatings feature ice adhesion values (τ) that are around one-fourth of those measured on the homogeneous PU coating derived from curing P1 with HDIT. However, the τ values of the DBP-lubricated coatings quickly increase with the number of icing/de-icing cycles presumably due to the shedding of the highly swollen surface layer with ice removal. The lubrication of an optimized LICROS coating with acetyl tributyl citrate (ATBC), which swells the coating much less than DBP, sustains low τ values of ∼60 kPa for 15 icing/de-icing cycles without showing signs of deterioration. LICROS coatings have nanoindentation hardness and wear resistance comparable with those of the cured homogeneous P1 coating but much better than those of the cured P2 coating. Since a robust LICROS coating can be made from P1 and P2 at a mass ratio of 97.5/2.5, the weight fraction of the expensive FC 6 -MA component used in the final coating is only 0.12%. Thus, this paper reports an approach to making inexpensive coatings with low ice adhesions but high wear resistance.