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A Bubble-Powered Micro-Rotor: Conception, Manufacturing, Assembly And Characterization, Jonathan Kao, Xiaolin Wang, John Warren, Jie Xu, Daniel Attinger
A Bubble-Powered Micro-Rotor: Conception, Manufacturing, Assembly And Characterization, Jonathan Kao, Xiaolin Wang, John Warren, Jie Xu, Daniel Attinger
Daniel Attinger
A steady fluid flow, called microstreaming, can be generated in the vicinity of a micro-bubble excited by ultrasound. In this paper, 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 of 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 µm rotors micromanufactured in SU-8 resin is then presented. Variables controlling the rotation speed and rotor stability are investigated, such …
Control And Ultrasonic Actuation Of A Gas–Liquid Interface In A Microfluidic Chip, Jie Xu, Daniel Attinger
Control And Ultrasonic Actuation Of A Gas–Liquid Interface In A Microfluidic Chip, Jie Xu, Daniel Attinger
Daniel Attinger
This paper describes the design and manufacturing of a microfluidic chip, allowing for the actuation of a gas–liquid interface and of the neighboring fluid. The first way to control the interface motion is to apply a pressure difference across it. In this case, the efficiency of three different micro-geometries at anchoring the interface is compared. Also, the critical pressures needed to move the interface are measured and compared to a theoretical result. The second way to control the interface motion is by ultrasonic excitation. When the excitation is weak, the interface exhibits traveling waves, which follow a dispersion equation. At …
Ionic Liquids With Perfluorinated Alkoxyaluminates, Tudor Timofte, Anja V. Mudring, Slawomir Pitula
Ionic Liquids With Perfluorinated Alkoxyaluminates, Tudor Timofte, Anja V. Mudring, Slawomir Pitula
Anja V. Mudring
Ionic liquids with the weakly coordinating perfluoroalkoxyaluminate anions, Al(ORF)4-, are obtained by a metathesis reaction of LiAl(ORF)4 and [bmim]Cl or [bmpyr]Cl in high yields. The compounds [bmim][Al(hfip)4] and [bmpyr][Al(hfip)4] have surprisingly low viscosities at elevated temperatures (60 °C) and an exceptionally high electrochemical window, which might render them useful for certain applications.