Highly Stretchable Superhydrophobic Composite Coating Based on Self‐Adaptive Deformation of Hierarchical Structures

Abstract

With the rapid development of stretchable electronics, functional textiles, and flexible sensors, water-proof protection materials are required to be built on various highly flexible substrates. However, maintaining the antiwetting of superhydrophobic surface under stretching is still a big challenge since the hierarchical structures at hybridized micro-nanoscales are easily damaged following large deformation of the substrates. This study reports a highly stretchable and mechanically stable superhydrophobic surface prepared by a facile spray coating of carbon black/polybutadiene elastomeric composite on a rubber substrate followed by thermal curing. The resulting composite coating can maintain its superhydrophobic property (water contact angle ≈170° and sliding angle <4°) at an extremely large stretching strain of up to 1000% and can withstand 1000 stretching-releasing cycles without losing its superhydrophobic property. Furthermore, the experimental observation and modeling analysis reveal that the stable superhydrophobic properties of the composite coating are attributed to the unique self-adaptive deformation ability of 3D hierarchical roughness of the composite coating, which delays the Cassie-Wenzel transition of surface wetting. In addition, it is first observed that the damaged coating can automatically recover its superhydrophobicity via a simple stretching treatment without incorporating additional hydrophobic materials.

Stretchable Hydrophobic Surfaces and Self-Cleaning Applications

“…Phase change material, such as n-octadecane, can be used to create a reversible exchange of the wetting state 12,13 ; however, the reversible exchange of the wetting state is limited with the small temperature range at which the phase change material undergoes melting and solidification. The surface hydrophobicity can also maintain for the hierarchical wrinkle stretchable surfaces even after being repeatedly stretched 14,15 . The reversible hydrophobic surface characteristics allow the substrates used in many applications such as textile and sensors.…”

Robust Fluorine‐Free Superhydrophobic PET Fabric Using Alkaline Hydrolysis and Thermal Hydrophobic Aging Process

“…This might be due to the irreversibly transformed wetting state from the Cassie state to the Wenzel state depending on the surface tension of the droplets. If the droplet sits atop the surface having nanocraters and an air‐gap formed between the nanocraters, it seems to be in a superhydrophobic or Cassie state . On the other hand, if the droplet falls between the nanocraters and fills them, it can be a hydrophobic or Wenzel state .…”

Inexpensive and non-fluorinated superhydrophobic concrete coating for anti-icing and anti-corrosion

“…It will also greatly increase the life span of concrete materials and create more economic benefits for many large projects, such as bridges, offshore engineering, and seaports. According to the main composition of materials, a superhydrophobic coating may include cyanoacrylates, 5 epoxy resin, 6 polyelectrolyte complexes, 7 ammonium polyphosphate, 8 candle soot, 4,[9][10][11] carbon black/polybutadiene elastomeric composite, 12 wax, 13 calcium carbonate nanoparticles, 14 graphene oxide/diatomaceous earth/PDMS composite, 15 TiO 2 , 3,16 SiO 2 , [17][18][19][20][21] PDMS, 22 Ag nanoparticles, 23 et al However,low adhesion force between the coating and substrate, low mechanical strength, high cost, and even extensive use of fluorocarbon materials which is potentially toxic to humans indicate that the state-of-the-art methods are difficult to scale-up in large industrial concrete projects. A simultaneous demonstration of the aforementioned four features is a major challenge.…”

“…It will also greatly increase the life span of concrete materials and create more economic benefits for many large projects, such as bridges, offshore engineering, and seaports. According to the main composition of materials, a superhydrophobic coating may include cyanoacrylates, 5 epoxy resin, 6 polyelectrolyte complexes, 7 ammonium polyphosphate, 8 candle soot, 4,9-11 carbon black/polybutadiene elastomeric composite, 12 wax, 13 calcium carbonate nanoparticles, 14 graphene oxide/diatomaceous earth/PDMS composite, 15 TiO 2 , 3,16 SiO 2 , [17][18][19][20][21] PDMS, 22 Ag nanoparticles, 23…”