Magnetically driven superhydrophobic meshes with the capacity of moving at air/water and oil/water interfaces

Abstract

The hazard of oil contamination in sewage detection has drawn great attention and gives rise to some technical difficulties for pipe inspection applications using robots. In the attempt to face this challenge, a magnetically controlled micro-robot model was designed to allow it to move directionally on oil-contaminated water. In this design, magnetically responsive mesh supports were used; moreover, these were required to float at air/water and oil/water interfaces. Optimal analysis of force shows the importance of superhydrophobicity for the floatability of mesh supports at these two interfaces. Accordingly, mesh surfaces were decorated to produce superhydrophobicity by a simple fluorination process. A superhydrophobic mesh was experimentally verified to freely float at both interfaces, providing a large supporting force to improve its floating stability. Guided by a magnetic field, the micro-robot model with mesh supports could float, move and rotate at air/water and oil/water interfaces in a closed system. Therefore, our findings could offer guidance for the design of aquatic micro-devices to detect sewage in bent or small-sized pipes.