Microactuators applications

K. G. Brooks, J. Chen, K. R. Udayakumar, and L. E. Cross. Lead Zirconate Titanate Stanate Thin Films for Large Strain Microactuator Applications. ... 

The sensitivity of hydrogels to a large number of physical factors like temperature [149], electrical voltage [150], pH [151-153], concentration of organic compounds in water [154], and salt concentration [155] make them promising materials for a broad range of applications as microsensors [156] and microactuators [154] in MEMS devices. 

Combustion in small volumes has recently become of interest to applications of micropower generation [77-81], micropropulsion [82-94], microengines [95-102], microactuation [103-105], and microfuel reforming for fuel cells... 

Optical microactuators like a micromirror for scanning applications have been proposed by Orsier et al. (1996). A two-dimensional bimorph (Si 4- magnetostrictive film) is driven remotely by two differently oriented magnetic fields working at different frequencies in order to obtain the bending and torsional vibrations due to the magnetostrictive strain. 

E.W.H. lager, E. Smela, O. Inganas and I Lundstrom, Applications of polypyrrole microactuators. In Smart Structures and Materials 1999 Conference. International Socirty of Optical Engineering, Newport Beach, CA, 1999. 

MEMS find wide applications in microsensors such as acoustic waves, biomedical, chemical, inertia, optical, pressure, radiation, and thermal microactuators like valves, pumps, and microfluidics electrical and optical relays and switches grippers tweezers and tongs as well as linear and rotary motors, etc., in various fields. They also find application in microdevice components such as palmtop reconnaissance aircrafts, minirobots and toys, microsurgical and mobile telecom equipment, read/ write heads in computer storage systems, as well as ink-jet printer heads [4]. 

Pollack MG, Fair RB, Shenderov AD (2000) Electrowetting-based microactuation of liquid droplets for microfluidic applications. Appl Phys Lett 77(11) 1725-1726... 

Microactuators can be implemented in one or more degrees of freedom, leading to another way to classify them as linear (or prismatic), rotary (or revolute), in-plane (1D-3D), and out of plane (1D-6D). A micromotor contains several movable parts, including the microactuator and a transmission system. The transmission system consists of bending (or flexture) joints and links, rigid links, stick-and-slip contact elements, or micromechanical hinges. Like macroscale actuators, microactuators are chosen for different applications based on tradeoffs between ... 

Microactuators are also used in microfluidics for many applications including lab-on-a-chip and implantable drug dehvery systems. Such fluidic actuators can be categorized as follows ... 

The main focus of research on temperature-sensitive hydrogels as microactuators in microfluidic devices has been on microvalves. Hydrogel actuators have a distinct advantage for microvalve applications since they are very soft and encapsulate dust particles encountered in microfluidic flows. Normally, these particles... 

The microactuators have shown success in various flow control applications. The detailed criteria for characterization of successful synthetic jet formation are evolving. There are limited data on the synthetic jet formation constant... 

Because polypyrrole operates in aqueous electrolytes at room temperature, the largest niche for conjugated polymer microactuators is biomedical applications. Commercialization efforts are underway for blood vessel coimectors, a valve to prevent urinary incontinence, and a Braille display [25,122,133]. One area that requires further research is the temperature-dependence of actuator metrics, because for biomedical applications the devices must be operated at 37°C. In PPy(DBS) microactuators, strain increases from room temperature to body temperature by 45%, and they are 250% faster, but the blocked force drops [126]. 

The next step for this technology is the development of dry microactuators that can work outside of a liquid. On the macroscale, it has been demonstrated that conjugated polymers can actuate in ionic liquids [132,134], These room temperature liquid salts can be incorporated into gels [135], which wfll allow the fabrication of patterned electrolyte containing solid layers using photolithographic techniques. This development will expand the range of possible applications. 

Lee, A.P, K.G. Hong, J. Trevino, and M.A. Northrop. 1994. Thin film conductive polymer for microactuator and micromuscle applications. Presented at Dynamic and Systems and Gontrol Session, International Mechanical Engineering Gongress, Ghicago, USA. 

---