Engineering Light-Driven Rod-Shaped Micromotors for Exhibiting Controlled and Tunable Multimode Swimming

Abstract

The recent era of research has been focused on attaining precise and adjustable propulsion modes in micromotors, with remarkable implications in microrobotics and active-matter applications. This study introduces a novel design of rod-shaped micromotors featuring light-driven motion and wavelength-dependent multimodal swimming behavior. The micromotors are fabricated through the Glancing Angle Deposition (GLAD) technique, which offers a flexible approach to engineering surfaces by incorporating photocatalytic materials (TiO2 and Cu2O) at specific locations. Here, three distinct designs of micromotors (titania, hybrid-1, and hybrid-2) are presented that are programmed to showcase diverse behaviors of movements (linear, helical, and axial rotation) when exposed to a specific wavelength. The application of light facilitates convenient control over activity and mode switching by altering between UV and visible ranges. Numerical modeling using a finite element approach is performed to validate the experimental results, demonstrating excellent agreement with the experimental findings. The present study is anticipated to be helpful in tailoring such complex micro/nanoscale advanced functional materials with intricating swimming modes desired for various applications in micro/nanorobotics.