Ultrasound-Modulated Bubble Propulsion of Chemically Powered Microengines

Abstract

Video S1. Bubble evolution and ejection behavior of the 'braking' mechanism of the chemically-powered microengines. Video S2. Ultrasound triggered 'stop and go' of a micromotor. Video S3. Speed modulation of a microengine by tailoring the ultrasound power.Video S4. The influence of ultrasound on a superfast moving micromotor.

Fabrication of Micro/Nanoscale Motors

“…Rapid and reversible stopping and starting of bubble-propelled microtubes is possible with the use of an ultrasound field. 217 Application of an ultrasound field disrupts normal bubble evolution and ejection by inducing the growth and aggregation of bubbles, thus hindering the movement of the microtubes. Rapid "stop−go" switching of microtube motion can be achieved by "on/off" ultrasound activations ( Figure 13G).…”

Reversible Swarming and Separation of Self-Propelled Chemically Powered Nanomotors under Acoustic Fields

“…[1][2][3] The cell was made in a steel plate (50 mm x 50 mm x 0.94 mm) with a 240 μm Kapton tape as a protective layer, and a sample reservoir at the center (1 mm), covered by a 18 mm x 18 mm x 0.15 mm glass slide for ultrasound reflection. The piezoelectric transducer which produces the ultrasound waves (Ferroperm PZ26 disk 10 mm diameter, 0.5 mm thickness) was attached to the bottom center of the slide by conductive epoxy glue.…”

Interplay Between Mechanochemistry and Sonochemistry

“…It would appear that the swimming trajectory of an object is governed by the balance between the orienting force induced by the physical field and the effects that randomize particle orientations, such as rotary Brownian motion and/or a tumbling mechanism like that of flagella in bacteria [126]. Wang et al have recently displayed the modulating effect of an ultrasonic field on the bubble propulsion of a chemically-fuelled microengine [127]. The latter, fabricated by electrodeposition, consists of a poly(3,4-ethylenedioxythiophene) (PEDOT)/Ni/Pt tubular arrangement (15 m long, 5 m diameter in its wide side).…”