3D‐Printed Underwater Super‐Oleophobic Shark Skin toward the Electricity Generation through Low‐Adhesion Sliding of Magnetic Nanofluid Droplets

Abstract

Sustainable energy supply by converting mechanical to electric energy is critical for flexible electronic technologies, soft robots, and biomedical applications. The development of magnetoelectric conversion approaches requires new strategies with lightweight, small, and portable features. To address this need, an underwater magnetic nanofluid droplet‐based generator (UMNDG) is designed to convert the mechanical energy of sliding droplets to electricity. The UMNDG consists of four parts: 3D‐printed underwater superoleophobic surface bioinspired by shark skin, oily magnetic nanofluid droplets, bottom coil, and magnetic part. By improving the manufacturing parameters of 3D‐printed shark skin, underwater superoleophobic and low‐adhesion surfaces can be fabricated, allowing for the magnetic nanofluid droplets to slide upon the surfaces freely. When the magnetic nanofluid droplets slide/leave the bottom coil/magnet region, the magnetic flux passes through the coil changes, yielding the generation of electricity. Maxwell simulation is used to study related working mechanism. Finally, a ladder‐type setup consisting of four UMNDGs is assembled in series, enabling to trigger the lighting of a LED bulb by continuous sliding of magnetic nanofluid droplets. Such a setup design may find use in a wide range of applications, from flexible electronic technologies to bio‐inspired materials that interface with magnetic nanofluid systems.

Janus Membrane Decorated by MXene Multilayered Nanoflakes for Wet–Thermal Management

“…The larger the fiber diameter, the smaller the water contact angle is. It is known that increasing the surface roughness leads to the hydrophilic surface becoming more “water-loving” and the hydrophobic surface becoming more “water-hating”. , The asymmetric wettabilities of hydrophobic PU-E and hydrophilic MXene@PDA-PU contribute to the directional water transport capacity. That is, with the increase in fiber diameter, the roughness and hydrophobicity of the PU-E decreased.…”

Robust and durable liquid-repellent surfaces

“…Besides the above-discussed TENGs, electromagnetic induction on liquid-repellent surfaces has also been exploited to construct electricity generators. [678][679][680] As shown in Fig. 71a, Ma et al proposed a superhydrophobic surface-based magnetoelectric system that could generate electricity from falling water droplets via mechanical-electrical conversion.…”

“…Similarly, electricity generation under water by using oily magnetic nanofluid droplet sliding on underwater superoleophobic surface has also been reported. 680…”

Recent Progress on Bioinspired Antibacterial Surfaces for Biomedical Application

“…The superhydrophobic skin endowed it with an anti-adhesion property to protect springtails from bacterial attaching and infection [ 39 ]. Shark’s hydrophobic skin, leveraging flat scales or dermal denticle arrays, offers another ingenious strategy to prevent the attachment and growth of microorganisms, with additional benefits in drag reduction ( Figure 2 D) [ 40 , 41 , 42 , 43 ].…”