Material Selection for Optimal Design of Thermally Actuated Pneumatic and Phase Change Microactuators

Srinivasan, Prasanna; Spearing, S. Mark

doi:10.1109/jmems.2009.2013385

Cited by 8 publications

(4 citation statements)

References 28 publications

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“…from Krulevitch et al (1996) (thermopneumatic, bimetallic, and piezoelectric), Gilbertson and Busch (1996) (SMA, electromagnetic, and electrostatic), and Srinivasan and Spearing (2009) (PCM). The maximum value noted for PCM here, is from paraffin wax.…”

Section: Introductionmentioning

confidence: 99%

Review on miniaturized paraffin phase change actuators, valves, and pumps

Ogden

Klintberg

Thornell

et al. 2013

Microfluid Nanofluid

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During the last fifteen years, miniaturised paraffin actuation has evolved through the need of a simple actuation principle, still able to deliver large strokes and high actuation forces at small scales. This is achieved by the large and rather incompressible volume expansion associated with the solid-to-liquid phase transition of paraffin. The common approach has been to encapsulate the paraffin by a stiff surrounding that directs the volume expansion towards a flexible membrane, which deflects in a directed stroke. However, a number of alternative methods have also been used in the literature. The most common applications to this date have been switches, positioning actuators, and microfluidic valves and pumps. This review will treat the historical background, as well as the fundamentals in paraffin actuation, including material properties of paraffin. Besides reviewing the three major groups of paraffin actuator applications; actuators, valves, and pumps, the modelling done on paraffin actuation will be explored. Furthermore, a section focusing on fabrication of paraffin microactuators is also included. The review ends with conclusions and outlook of the field, identifying unexplored potential of paraffin actuation.The final publication is available at Springer via http://dx

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Section: Introductionmentioning

confidence: 99%

Review on miniaturized paraffin phase change actuators, valves, and pumps

Ogden

Klintberg

Thornell

et al. 2013

Microfluid Nanofluid

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“…These values are still below the limit of thermal alkane PCM systems, which can reach up to 9 J cm –3 . [ 46 ]…”

Section: Resultsmentioning

confidence: 99%

Using Small Molecule Absorbers to Create a Photothermal Wax Motor

Lui

Bardeen

2021

Small

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Organic phase change materials are used in actuators like wax motors. The solid→liquid phase transition that drives expansion is commonly induced by resistive heating that requires an electrical connection. The use of light to generate a phase change provides a non‐contact way to power wax motors. Here, it is demonstrated that small molecules can act as absorbers to enable a photoinduced solid→liquid melting transition in eicosane, a low molecular weight phase change material. Three different small molecule absorbers are utilized: (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO), azobenzene (AZOB), and guaiazulene (GAZ). The GAZ/eicosane mixture is characterized in detail because its absorption extends out to 750 nm, opening up the possibility of using near‐infrared diodes as the photon source. The GAZ/eicosane composite is incorporated into a commercial wax motor assembly and 532 nm laser light is used to lift up to 400 g. The temporal response, work and force output, and efficiency are measured, and no loss of lifting capability or degradation is observed after ten cycles of irradiation. The incorporation of small aromatic molecules with low‐energy absorption features into phase change materials can provide a general way to make light powered wax motors.

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“…The response time strongly depends on the input power for the heating process [26], and on the material choice for the cooling process [27]. At the moment no active cooling is performed.…”

Section: Response Time Analysismentioning

confidence: 99%

Completely integrated, thermo-pneumatically tunable microlens

Zhang¹,

Aljasem²,

Zappe³

et al. 2011

Opt. Express

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An integrated tunable microlens, whose focal length may be varied over a range of 3 to 15 mm with total power consumption below 250 mW, is presented. Using thermo-pneumatic actuation, this adaptive optical microsystem is completely integrated and requires no external pressure controllers for operation. The lens system consists of a liquid-filled cavity bounded by a distensible polydimethyl-siloxane membrane and a separate thermal cavity with actuation and sensing elements, all fabricated using silicon, glass and polymers. Due to the physical separation of thermal actuators and lens body, temperature gradients in the lens optical aperture were below 4 °C in the vertical and 0.2 °C in the lateral directions. Optical characterization showed that the cutoff frequency of the optical transfer function, using a reference contrast of 0.2, varied from 30 lines/mm to 65 lines/mm over the tuning range, and a change in the numerical aperture from 0.067 to 0.333. Stable control of the focal length over a long time period using a simple electronic stabilization circuit was demonstrated.

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Material Selection for Optimal Design of Thermally Actuated Pneumatic and Phase Change Microactuators

Cited by 8 publications

References 28 publications

Review on miniaturized paraffin phase change actuators, valves, and pumps

Review on miniaturized paraffin phase change actuators, valves, and pumps

Using Small Molecule Absorbers to Create a Photothermal Wax Motor

Completely integrated, thermo-pneumatically tunable microlens

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