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ABSTRACT
Copolymers of vinylidene fluoride and trifluoroethylene (P(VDF-TrFE)) have been used in a variety of devices such as transducers, actuators and sensors because of their good electroactive properties. Our earlier work showed that the electric field-induced strain in P(VDF-TrFE) copolymers can be enhanced significantly after high energy proton irradiation. In this study, micromachined actuators using proton-irradiated P(VDF-TrFE) copolymer as the active element have been fabricated. P(VDF-TrFE) 70/30 mol% copolymer film with a thickness of ∼ 3.3 μ m was spin-coated on a silicon (Si) substrate. After etching the Si substrate by bulk micromachining, an actuator in the form of a suspended membrane was obtained. High energy proton irradiation with a dose of 107 Mrad was carried out to modify the properties of the copolymer film. The resonance characteristics of the actuators based on these irradiated copolymer films were studied and the displacement induced in the actuators was measured using a laser vibrometer. These types of polymer-based micromechanical systems have the advantages of being lightweight and have high toughness, thereby reducing the risk of breakage. By applying different d.c. bias voltages, the magnitude of the displacement induced in the actuator can be varied.
ACKNOWLEDEMENTS
Financial support from the Research Grants Council of The Hong Kong Special Administrative Region (Project PolyU 5147/02E) and the Centre for Smart Materials of The Hong Kong Polytechnic University.