The adaptive locomotion of shape-morphing helical microswimmer. (IMAGE)
Caption
(a) The printed hydrogel microswimmer was immersed into Fe3O4 nanoparticle suspension, gaining magnetism for the actuation test. (b) The magnetic microswimmer and Fe3O4 nanoparticle mass magnetisation curve were measured with Vibrating Sample Magnetometer (VSM). (c) Schematics of the magnetic actuation for pH-responsive helical microswimmer in contracted state and expanded state. The contracted microswimmer shows a tumbling motion with the rotation axis perpendicular to the helical axis. At the same time, the expanded one demonstrates corkscrewing motion with the rotation axis along the helical axis. The magnetic field is a constant rotating magnetic field (CRMF) with 15 mT strength and 5 Hz frequency. (d) Schematics and time-lapse image of the tumbling motion of contracted helical microswimmer, wherein V∥ indicates that the V is parallel to the B. (e) Schematics and time-lapse image of the corkscrewing motion of expanded helical microswimmer, wherein V⊥ means that V is perpendicular to the B. (f, g) The velocities of contracted and expanded microswimmer with different heights and diameters. (h) The dynamic transition process of microswimmer from tumbling to corkscrewing. The transition is realised by changing the pH value during the actuation of the microswimmer. (i) The reverse process compared with (h) from corkscrewing to tumbling due to the pH value increasing—scale bar: 50 μm.
Credit
bu Rui Li, Yuan Tao, Jiawen Li, Dongdong Jin, Chen Xin, Shengyun Ji, Chaowei Wang, Yachao Zhang, Yanlei Hu, Dong Wu, Li Zhang and Jiaru Chu.
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Credit must be given to the creator.
License
CC BY