A Parylene Bellows Electrochemical Actuator

Li, Po-Ying; Sheybani, Roya; Gutierrez, Christian; Kuo, Jen-Tsai; Meng, Ellis

doi:10.1109/jmems.2009.2032670

Cited by 101 publications

(121 citation statements)

References 38 publications

(47 reference statements)

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“…These bubbles cannot be easily terminated since the rate of the combustion reaction between the gases is negligibly low at room temperature and normal pressure. This is the main reason for a long response time observed in the DC electrolysis [19][20][21][22][23][24][25][26] . In the case of the alternating polarity process only nanobubbles are formed.…”

Section: Discussion Of the Response Timementioning

confidence: 99%

Electrochemical membrane microactuator with a millisecond response time

Uvarov

Lokhanin

Постников

et al. 2018

Sensors and Actuators B: Chemical

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Lack of fast and strong actuators to drive microsystems is well recognized. Electrochemical actuators are considered attractive for many applications but they have long response time (minutes) due to slow gas termination. Here an electrochemical actuator is presented for which the response time can be as short as 1ms. The alternating polarity water electrolysis is used to drive the device. In this process only nanobubbles are formed. The gas in nanobubbles can be terminated fast due to surface assisted reaction between hydrogen and oxygen that happens at room temperature. The working chamber of the actuator contains concentric titanium electrodes; it has a diameter of 500 µm and a height of 8 µm. The chamber is sealed by a polydimethylsiloxane (PDMS) membrane of 30µm thick. The device is characterized by an interferometer and a fast camera. Cyclic operation at frequency up to 667 Hz with a stroke of about 30% of the chamber volume is demonstrated. The cycles repeat themselves with high precision providing the volume strokes in picoliter range. Controlled explosions in the chamber can push the membrane up to 90 µm.

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Section: Discussion Of the Response Timementioning

confidence: 99%

Electrochemical membrane microactuator with a millisecond response time

Uvarov

Lokhanin

Постников

et al. 2018

Sensors and Actuators B: Chemical

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show abstract

“…Most advanced piezoelectric actuators [7] are fast and strong, but not compatible with microtechnology, need a high voltage for actuation and have a small stroke. Actuators using electrochemical decomposition of water were also discussed in many papers [8][9][10][11][12][13][14], but they are notoriously slow. One can produce a large amount of gas in a short time, but it is impossible to get rid of this gas fast, as well.…”

Section: Introductionmentioning

confidence: 99%

Overcoming the Fundamental Limit: Combustion of a Hydrogen-Oxygen Mixture in Micro- and Nano-Bubbles

et al. 2016

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Combustion reactions quench in small volumes due to fast heat escape via the volume boundary. Nevertheless, the reaction between hydrogen and oxygen was observed in nano-and micro-bubbles. The bubbles containing a mixture of gases were produced in microsystems using electrochemical decomposition of water with a fast switching of voltage polarity. In this paper, we review our experimental results on the reaction in micro-and nano-bubbles and provide their physical interpretation. Experiments were performed using microsystems of different designs. The process was observed with a stroboscope and with a vibrometer. The latter was used to measure the gas concentration in the electrolyte and to monitor pressure in a reaction chamber covered with a flexible membrane. Information on the temperature was extracted from the Faraday current in the electrolyte. Since the direct observation of the combustion is complicated by the small size and short time scale of the events, special attention is paid to the signatures of the reaction. The mechanism of the reaction is not yet clear, but it is obvious that the process is surface dominated and happens without significant temperature increase.

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“…2 Micro-electro-mechanical systems (MEMS) technology offers the potential to develop implantable drug delivery devices with miniaturized size and effective control. Among the preliminary studies, MEMS fabrication-based electrolytic pumps are receiving considerable interest [3][4][5][6] for delivering a variety of drugs due to their ability of transforming electrical energy directly into mechanical work through swelling, bending, and other deformations. Electrolytic actuation, compared to other actuation mechanisms, usually offers the preponderant advantages of stability, low power consumption, and easy operation.…”

Section: Introductionmentioning

confidence: 99%

A remotely operated drug delivery system with an electrolytic pump and a thermo-responsive valve

Zaher

Yassine

et al. 2015

Biomicrofluidics

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Implantable drug delivery devices are becoming attractive due to their abilities of targeted and controlled dose release. Currently, two important issues are functional lifetime and non-controlled drug diffusion. In this work, we present a drug delivery device combining an electrolytic pump and a thermo-responsive valve, which are both remotely controlled by an electromagnetic field (40.5 mT and 450 kHz). Our proposed device exhibits a novel operation mechanism for long-term therapeutic treatments using a solid drug in reservoir approach. Our device also prevents undesired drug liquid diffusions. When the electromagnetic field is on, the electrolysisinduced bubble drives the drug liquid towards the Poly (N-Isopropylacrylamide) (PNIPAM) valve that consists of PNIPAM and iron micro-particles. The heat generated by the iron micro-particles causes the PNIPAM to shrink, resulting in an open valve. When the electromagnetic field is turned off, the PNIPAM starts to swell. In the meantime, the bubbles are catalytically recombined into water, reducing the pressure inside the pumping chamber, which leads to the refilling of the fresh liquid from outside the device. A catalytic reformer is included, allowing more liquid refilling during the limited valve's closing time. The amount of body liquid that refills the drug reservoir can further dissolve the solid drug, forming a reproducible drug solution for the next dose. By repeatedly turning on and off the electromagnetic field, the drug dose can be cyclically released, and the exit port of the device is effectively controlled. V C 2015 AIP Publishing LLC.

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A Parylene Bellows Electrochemical Actuator

Cited by 101 publications

References 38 publications

Electrochemical membrane microactuator with a millisecond response time

Electrochemical membrane microactuator with a millisecond response time

Overcoming the Fundamental Limit: Combustion of a Hydrogen-Oxygen Mixture in Micro- and Nano-Bubbles

A remotely operated drug delivery system with an electrolytic pump and a thermo-responsive valve

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