Chemical/Light‐Powered Hybrid Micromotors with "On‐the‐Fly" Optical Brakes. Issue 27 (1st June 2018)

• Record Type: Journal Article
• Authors: Chen, Chuanrui; Tang, Songsong; Teymourian, Hazhir; Karshalev, Emil; Zhang, Fangyu; Li, Jinxing; Mou, Fangzhi; Liang, Yuyan; Guan, Jianguo; Wang, Joseph
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 27(2018)
• Page Start: 8110
• Page End: 8114
• Publication Date: 2018-06-01
• Subjects: chemical propulsion -- Janus micromotors -- optical brakes -- photocatalytic reactions; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201803457
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Hybrid micromotors capable of both chemically powered propulsion and fuel‐free light‐driven actuation and offering built‐in optical brakes for chemical propulsion are described. The new hybrid micromotors are designed by combining photocatalytic TiO2 and catalytic Pt surfaces into a Janus microparticle. The chemical reactions on the different surfaces of the Janus particle hybrid micromotor can be tailored by using chemical or light stimuli that generate counteracting propulsion forces on the catalytic Pt and photocatalytic TiO2 sides. Such modulation of the surface chemistry on a single micromotor leads to switchable propulsion modes and reversal of the direction of motion that reflect the tuning of the local ion concentration and hence the dominant propulsion force. An intermediate Au layer (under the Pt surface) plays an important role in determining the propulsion mechanism and operation of the hybrid motor. The built‐in optical braking system allows "on‐the‐fly" control of the chemical propulsion through a photocatalytic reaction on the TiO2 side to counterbalance the chemical propulsion force generated on the Pt side. The adaptive dual operation of these chemical/light hybrid micromotors, associated with such control of the surface chemistry, holds considerable promise for designing smart nanomachines that autonomously reconfigure their propulsion mode for various on‐demand operations. Abstract : Brake lights : A hybrid TiO2 /Au/Pt Janus micromotor with Pt‐based catalytic propulsion and a TiO2 ‐based light‐driven propulsion mode is presented. Depending on the relative rates of the chemical reactions on opposite sides of the Janus micromotor, the propulsion forces can be easily tuned by changing the light intensity or fuel concentration, enabling switching of the dominating propulsion mode or halting the motion at will.