Light-controlled two-dimensional TiO plate micromotors.

In this work, UV light-controlled two-dimensional (2D) TiO plate micromotors are demonstrated for the first time. The 2D TiO micromotors are produced by the well-known anodic oxidation method in combination with a cracking and separation process. When the motor is placed in HO aqueous solution under UV irradiation, oxygen bubbles are generated in the holes of the TiO membrane. The 2D micromotor thus moves upon O bubbles under its own weight. In contrast to bubble-propelled micromotors, which require an addition of surfactants to chemical fuels, the 2D micromotor is capable of moving in aqueous HO solution without surfactants. Moreover, speed of the 2D TiO micromotor can be controlled by the intensity of the UV light. Such surfactant-free micromotors and their facile fabrication hold considerable promise for diverse practical applications in the biomedical and energy fields, for example, and in new materials.