A bubble-powered micro-rotor: conception, manufacturing, assembly and characterization

Abstract

A steady fluid flow, called microstreaming, can be generated in the vicinity of a microbubble excited by ultrasound. In this article, we use this phenomenon to assemble and power a microfabricated rotor at rotation speeds as high as 625 rpm. The extractible power is estimated to be on the order of a few femtowatts. A first series of experiments with uncontrolled rotor shapes is presented, demonstrating the possibility of this novel actuation scheme. A second series of experiments with 65 m rotors micromanufactured in SU-8 resin are presented. Variables controlling the rotation speed and rotor stability are investigated, such as the bubble diameter, the acoustic excitation frequency and amplitude, and the rotor geometry. Finally, an outlook is provided on developing this micro-rotor into a MEMS-based motor capable of delivering tunable, infinitesimal rotary power at the microscale.

3-D manipulation of millimeter- and micro-sized objects using an acoustically excited oscillating bubble

“…As opposed to the results in Marmottant et al (2006); Marmottant and Hilgenfeldt (2003), it is observed in our preliminary study (Chung et al 2007) and Kao et al (2007) that when larger objects (several 10 lm or larger) are placed close to an oscillating bubble on a 2-D solid plane, they do not follow vortical flow paths but are attracted to the bubble surface orbiting on or around the oscillating bubble (Fig. 1b).…”

Microscopic Engine Powered by Critical Demixing

“…For example, microrotators have been realized by transferring the orbital and spin momentum of light to microscopic particles [5,6] or by employing rotating magnetic fields [7][8][9]. Several prototypes of microscopic heat engines have been realized exploiting the nucleation of a vapor bubble inside a silicon microcavity, some of them down to a working volume of only 0.6 mm 3 [10][11][12]. More recently, optically trapped particles have been employed to reproduce microscopic versions of the Stirling and Carnot cycles, and to study their stochastic thermodynamic properties [13,14].…”

Controllable generation and manipulation of micro-bubbles in water with absorptive colloid particles by CW laser radiation

“…Gas and vapor bubbles of nano-and micrometric sizes in aqueous solutions are interesting for many fundamental and applied research problems: thermodynamic studies of liquid superheating and phase transitions in nano-scale [1][2][3][4][5][6], microhydraulic and micromachinery manipulation [7,8], microoptics [9], diverse biomedical applications including cell investigations, sorting, precise drug delivery and therapy [11][12][13].…”