Design, modeling, fabrication, and performances of bridge-type high-performance electroactive polymer micromachined actuators

Bridge-type high- performance polymer micromachined actuators (PMATs) based on an electroactive polymer, modified poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer had been designed, modeled, fabricated, and characterized. The results show that the material enables the PMAT to exhibit a high stroke level (60 μm displacement with 1 mm lateral dimension microactuator) with high-load capability and high-displacement voltage ratio (DVR) over a broad frequency range (>100 kHz). The stroke reduction in fluid (Silicone oil) is less than 5% comparing with the displacement in air. Impedance analysis and displacement measurement indicate that the PMAT has strong resonance behavior and the resonance frequency can be tuned by varying the dc bias field. Furthermore, the resonance peak, as expected by theoretical study, shifted to 6.5 times lower in fluid than in air with the mechanical Q value reduction less than 40%. In addition, the performance of the PMAT was modeled based on the elastic and electromechanical properties of the materials utilized in the PMAT and the configuration of the device. The comparison between the model and the experimental result shows a good agreement and validates the model as an effective method for the future development of PMAT for various applications. The high frequency response and respected performance in fluid medium demonstrate that the PMAT has potential for high performance MEMS components in the applications of microfluid systems, air dynamic control, under water transducers, and mass sensors, etc.