Superhydrophobic, mechanically durable coatings for controllable light and magnetism driven actuators

Although some groundbreaking work has proved the feasibility of non-contact Marangoni propulsion generated by combination of the superhydrophobicity and photothermal effect, there are still challenges including the strong interfacial adhesion, multifunctional structural design and superior durability. In this paper, a simple two-step spraying method is used to prepare superhydrophobic and multifunctional fluorinated acidified carbon nanotubes (F-ACNTs)/Fe3O4 nanoparticles/polydimethylsiloxane (PDMS) coatings. The introduction of Fe3O4 nanoparticles and F-ACNTs not merely improve the surface roughness but also endow the coating with the outstanding magnetic property and photothermal conversion performance. The PDMS can reduce the surface energy and also improve the interfacial adhesion between the nanofillers and the substrate (the filter paper). The superhydrophobicity can be maintained when the material experiences abrasion, near-infrared (NIR) light irradiation and acid treatment, exhibiting outstanding durability. The highly stable superhydrophobic coating introduces a thin layer of air to decrease the drag force between the filter paper and the water surface, and can be used for controlled self-propelled light-driven motion and magnetic-driven motion. The movement can be manipulated by adjusting the direction of the incident NIR light and magnetic field. In particular, the superhydrophobic and superoleophilic coating based actuators can be easily driven to the oil-contaminated area on the water surface by using a magnet for high efficiency oil removal. This work provides a simple and universal strategy for developing intelligent and multi-responsive actuators possessing promising applications in various fields such as environmental protection, micro-robots and biomedicine. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study presents a simple two-step spraying method to prepare superhydrophobic and multifunctional coatings, which introduce Fe3O4 nanoparticles and F-ACNTs to improve surface roughness, magnetic property, and photothermal performance. The use of PDMS enhances interfacial adhesion and durability. The resulting coating maintains superhydrophobicity under various conditions and can be used for controlled self-propelled motion and oil removal with high efficiency.