P(VDF-TrFE) based electroactive polymers and their applications for macro and micro electromechanical devices

Electroactive polymers (EAPs) are novel polymeric materials that enable large displacement or strain under the stimulus of electrical field.; Among different EAPs that have been developed, P(VDF-TrFE) (poly(vinylidene fluoride-trifluoroethylene)) based electrostrictive polymers show great potential for many electromechanical applications due to their high strain level and high elastic energy.; To improve the mechanical quality of the uniaxially stretched films, the effect of annealing conditions on the electromechanical responses of high-energy electron irradiated P(VDF-TrFE) copolymers (HEEIP) was studied for one-step annealed films. Based on these results, a two-step annealing procedure is proposed and studied. Experimental results indicate that this approach can produce uniaxially stretched HEEIP films with much improved mechanical quality, meanwhile exhibiting the same or even better electromechanical response than that from the one-step annealed HEEIP films.; Based on the optimized P(VDF-TrFE) electroactive polymers, three classes of electromechanical devices have been studied in the device exploration part, including flextensional transducers, polymer based microactuators and microfluidic pumps.; Utilizing the irradiated PVDF-TrFE copolymer, a flextensional transducer was fabricated and optimized using Finite Element Analysis (FEA). The results show that the small device (1&inches; x 1&inches; in lateral dimension and a few mm in thickness) is capable of generating displacement at mm level in air with high load capability. The FEA modeling indicates that the performance of this flextensional device can be tailored by adjusting the parameters of the flextensional transducer.; To explore the potential applications of P(VDF-TrFE) based EAPs for BioMEMs and microfluidic devices, several types of polymer-based microactuators with different shapes and boundary conditions were studied and modeled using FEA, which provided a design reference for micropump and microvalve applications.; All these results indicate that P(VDF-TrFE) based electrostrictive polymers are very promising for many electromechanical device applications. Utilizing P(VDF-TrFE) based electroactive polymers, all-polymer disposable BioMEMs and microfluidic devices could be developed in the future for biomedical and biochemical applications. (Abstract shortened by UMI.)...