This paper reports an easy method to prepare a transparent superhydrophobic coating which shows a robust resistance to oil contamination, knife-scratch, sandpaper abrasion and strong acid/base attack.
18 January 2020 in Journal of Materials Chemistry A
Although superhydrophobic materials have attracted much research interest in anti-icing, some controversy still exists. In this research, we report a cost-effective method used to verify the contribution of area fraction to ice adhesion strength. We tried to partially-embed silica nanoparticles into microscale fabrics of a commercial polyamide mesh. Then, the area fraction could be determined by altering the mesh size. Generally, the ice adhesion strength decreases as the area fraction decreases. An ice adhesion strength of ∼1.9 kPa and a delayed freezing time of ∼1048 s can be obtained. We attribute the low ice adhesion strength to the combination of superhydrophobicity and stress concentration. The superhydrophobicity prohibits the water from penetrating into the voids of the meshes, and the small actual contact area leads to stress concentration which promotes interfacial crack propagation. Moreover, our superhydrophobic mesh simultaneously exhibits a micro-nano hierarchical structure and a partially-embedded structure. Therefore, the as-prepared superhydrophobic mesh retained the icephobicity after 20 icing/deicing cycles, and maintained its superhydrophobicity even after 60 sandpaper-abrasion cycles and a 220 °C thermal treatment.
Stretchable superhydrophobic materials are of potential interest for next-generation multi-functional haptic technologies particularly suited for wearable device and artificial skin applications. However, the practical applications of stretchable superhydrophobic materials are hindered by some issues, such as low mechanical robustness, harmful chemicals, etc. Here, we partially embedded perfluorosilane-coated graphene into thermoplastic polyurethane (TPU) by a dissolution and resolidification method. Due to the exceptional physical properties of graphene, the resulting nanocomposites could maintain their superhydrophobicity after toleration of strain up to 400%, man-made destruction by hands or sandpapers, pollution by oil, immersion in various corrosive liquids, and heat treatment at 150 °C for 24 h. It should be noted that even under an ultra-large load of 2 kg (32.5 kPa pressure), this graphene composite could withstand the abrasion by sandpaper for 20.00 m without losing superhydrophobicity. More remarkably, the electrical resistance of this graphene superhydrophobic composite is sensitive to material deformation, and can be directly applied to gloves for real-time detection of human motions.