The large strain, high elastic modulus, and easy processing of P(VDF-TrFE-CFE) electrostrictive terpolymer make it
very attractive to replace low strain piezoceramics and piezopolymers in many applications with much improved
performance. In this paper, a compact polymer actuator is developed utilizing the electrostrictive terpolymer, which
is suitable for full page Braille Display and graphic display. Key issues related to the reliability of electroactive
polymers used in the compact actuators and for the mass fabrication of these polymer actuators are investigated.
Making use of a recently developed conductive polymer, a screen printing deposition method was developed which
enables direct deposition very thin conductive polymer electrode layer (< 0.1 &mgr;m) with strongly bonding to the
terpolymer surface and short fabrication time. It was observed that the thin conductive polymer electrodes lead to the
self-healing of the polymer after electric breakdown. An EAP compact Braille actuator was designed and fabricated
with these terpolymer films wound on a spring core. The test results demonstrate that the EAP Braille actuator meets
all the functional requirements of actuators for refreshable full Braille display, which offers compact size, reduced
cost and weight.
Extremely large, lightweight, in-space deployable active and passive microwave antennas are demanded by future
space missions. This paper investigates the development of PVDF based piezopolymer actuators for controlling the
surface accuracy of a membrane reflector. Uniaxially stretched PVDF films were poled using an electrodeless
method which yielded high quality poled piezofilms required for this applications. To further improve the
piezoperformance of piezopolymers, several PVDF based copolymers were examined. It was found that one of
them exhibits nearly three times improvement in the in-plane piezoresponse compared with PVDF and P(VDF-TrFE)
piezopolymers. Preliminary experimental results indicate that these flexible actuators are very promising in
controlling precisely the shape of the space reflectors. To evaluate quantitatively the effectiveness of these PVDF
based piezopolymer actuators for space reflector applications, an analytical approach has been established to study
the performance of the coupled actuator-reflector-control system. This approach includes the integration of a
membrane reflector model, PVDF piezopolymer actuator model, solution method, and shape control law. The reflective Newton method was employed to determine the optimal electric field for a given actuator configuration and loading/shape error.
Recent advances in electroactive polymers including high field induced strain, high elastic energy density (~1 J/cm3), and relatively high energy conversion efficiency, approaching those of natural muscles, create new opportunities for many applications. Harvesting electric energy from mechanical sources such as a soldier during walking is one such example. Several electroactive polymers developed recently are briefly reviewed. The paper further presents analysis on the key steps in achieving energy harvesting effectively. It is shown that one may make use of smart electronics to modify the electric boundary conditions in the electroactive polymers during the energy harvesting cycle to realize higher energy conversion efficiency in the systems compared with the efficiency of the material itself. Due to the fact that the energy density of the electromagnetic based energy harvesting devices scales with the square root of the device volume, the paper shows that the electroactive polymers based energy harvesting devices exhibit higher energy density and therefore are more suitable for this application.