A new class of ferroelectric terpolymers having an exceptionally large electrostrictive response (>3%) induced by external electric field at ambient temperature comprise 50-80 mole % of vinylidene fluoride (VDF), 15-40 mole % of trifluoroethylene (TrFE) and 2-20 mole % of at least one bulky monomer, such as chlorotrifluoroethylene (CTFE) or hexafluoropropene (HFP). These semicrystalline terpolymers behave like a ferroelectric relaxor having a rapid electric field-induced mechanical response, due to a low Curie temperature (phase transition between polar and nonpolar crystalline domains at or near ambient temperature) and high dielectric constant. A combination of bulk polymerization and free radical polymerization using oxidation adducts of an organoborane as the free radical initiator may be used to prepare the terpolymers, such that the terpolymers are characterized by good processibility, high purity and uniform molecular structure.

An electroluminescent lamp has a luminescent layer placed between a rear electrode layer and a top electrode layer, which is at least partially transparent to light. The electrodes are arranged to excite the luminescent layer by applying a potential to the layer. An insulating layer is placed between the rear electrode layer and the luminescent layer, to increase the capacitance of the lamp. At least one of the layers includes a terpolymer, e.g., vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene. In some applications (e.g., in wristwatches), the luminescent layer includes phosphor, the insulating layer includes barium titanate, and the rear electrode includes silver, all distributed through the terpolymer. In other applications (e.g., in cellular phones or pagers), the rear electrode includes carbon.

There are disclosed new polymer materials having improved electric field induced strain levels, dielectric constants, and elastic energy densities for use in electromechanical and dielectric applications. Methods of manufacture of new polymer materials are also disclosed.

The present invention is a new class of terpolymers for use as high strain electrostrictive polymer films. More particularly, the invention is a class of electrostrictive terpolymers comprising vinylidene fluoride (VDF), trifluoroethylene (TrFE) and at least one monomer having at least one halogen atom side group. The monomer is preferably an ethylene-based monomer and preferably selected to favor gauche-type linkage along the polymer backbone. The halogen atom side group is preferably large enough to move or cause adjacent polymer chains to be farther apart from or away from each other than in the absence of such side group, but not so large that it would inhibit polymer crystallites from forming. The monomer is preferably a chloro-monomer such as chlorofluoroethylene (CFE). The chlorofluoroethylene (CFE) is preferably 1-chloro-2-fluoroethylene or 1-chloro-1-fluoroethylene. The chlorofluoroethylene (CFE) favors gauche-type linkage which favors high electrostrictive strains.

A thermal sensing polymeric device (110) such as a capacitor is fabricated from a layer of a copolymeric material (112) including polyvinylidene fluoride and a fluorinated ethylene. The fluorinated ethylene may be selected from the group including trifluoroethylene and tetrafluoroethylene. The thermal sensing polymeric device may be a capacitor fabricated of polyvinylidene fluoride-trifluoroethylene copolymeric material. In such an application, the capacitor device exhibits a change in capacitance as the temperature to which the device is exposed is changed. Specifically, as the temperature of the polymeric material crosses a threshold transition temperature, a substantial change in its capacitance is observed.