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Ultrasound-Modulated Bubble Propulsion of Chemically Powered Microengines

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posted on 18.06.2014, 00:00 by Tailin Xu, Fernando Soto, Wei Gao, Victor Garcia-Gradilla, Jinxing Li, Xueji Zhang, Joseph Wang
The use of an ultrasound (US) field for rapid and reversible control of the movement of bubble-propelled chemically powered PEDOT/Ni/Pt micro­engines is demonstrated. Such operation reflects the US-induced disruption of normal bubble evolution and ejection, essential for efficient propulsion of catalytic microtubular engines. It offers precise speed control, with sharp increases and decreases of the speed at low and high US powers, respectively. A wide range of speeds can thus be generated by tuning the US power. Extremely fast changes in the motor speed (<0.1 s) and reproducible “On/Off” activations are observed, indicating distinct advantages compared to motion control methods based on other external stimuli. Such effective control of the propulsion of chemically powered micro­engines, including remarkable “braking” ability, holds considerable promise for diverse applications.