Rutgers, the State University of New Jersey

USA as Represented by Secretary of the Navy

Brian A Newman

Jerry I Scheinbeim

Kook D Pae

Ji Su

A humidity sensor device which utilizes a humidity-sensitive piezoelectric polymer film as a transducer element. In a preferred embodiment a pair of excitation electrodes and a pair of pickup electrodes are provided on such a polymer film, a suitable excitation voltage is applied to the excitation electrodes and the resultant transverse piezoelectric effects are detected in the form of an electrical output voltage from the pickup electrodes. The electrical output signal is converted to the humidity value of the gaseous environment based on a prior calibration. Typically, an odd nylon such as nylon-11 or nylon-7 is used for the piezoelectric element and a rectangular, uniform and porous graphite films are deposited thereon as electrodes. The humidity sensor device of this invention can be used over a wide temperature range and can withstand repeated exposure to harsh temperature conditions over a long period of time.

Humidity sensor

Provided by this invention are piezoelectric laminate films wherein films of different polymers are in laminated relationship. The piezoelectric laminate film has at least one property which is superior to the corresponding property in the films used in the lamination to form the laminate. Also provided is a method for making the laminate.

Piezoelectric laminate films and processes for their manufacture

The provided invention is a novel electrostrictive driving device which comprises a sonic wave projector element having alternating electrodes and polymer material film layers. The device provides when subjected to a high bias voltage and a superimposed A.C. voltage, a high Angstroms/Volt response. Also, provided is a process for projecting sonic waves using the electrostrictive driving device of this invention.

Electrostrictive driving device, process for sonic wave projection and

This invention relates to a polarized material which is free or substantially free of mechanically-induced orientation and has polarization which is essentially stable up to the crystal melting temperature range of the polar crystals or to the softening temperature range or the glass transition temperature range of the polarized material if it is non-crystalline. A preferred polarized material provided is poly(vinylidene fluoride).

Polarized products

This invention relates to a process for making polarized material by forming a solution of a material capable of being polarized with a polarization solvent which can be removed by evaporation. The material in solution is poled to provide a polarized material which is free or substantially free of mechanically-induced orientation and which polarization is essentially stable up to the crystal melting point of the polar crystals or to softening point of the polarized material if non-crystalline. The polarization solvent can be removed from the solution as desired either to a reduced level or completely, such as during poling or before or after poling.

Process for making polarized material

This invention relates to a process for making polarized material by forming a solution of a material capable of being polarized with a polarization solvent. The material in solution is poled to provide a polarized material and during the poling the solvent is removed to the extent desired or totally to provide a polarized material which is free or substantially free of mechanically-induced orientation and which polarization is essentially stable up to the crystal melting point of the polar crystals or to softening point of the polarized material if non-crystalline.

Nylon 11 (.gamma.-phase) is electrically poled after it is crystallized f commercially available nylon 11 by rapidly crystallizing it from the molten state. The .gamma.-phase nylon 11 so obtained exhibits high piezoelectric properties when poled under different poling conditions at different temperatures. The electrically poled .gamma.-phase nylon 11 is used in a transducer.

Piezoelectric transducer using electrically poled .gamma.-phase nylon 11

Fabrication of unoriented phase I crystalline PVF.sub.2 is described wherein commercially available PVF.sub.2 phase II (crystalline form) is placed in a high pressure cell and its temperature is raised slightly over its melting point. The sample is then subjected to abrupt changes in high pressure and the temperature is dropped thereafter. The pressure is then reduced resulting in a product which contains both phase I and phase II forms of PVF.sub.2. The phase I content of the product varies from a few percent and up depending upon the pressure applied during the quenching step.

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Highland Park, NJ, United States of America

Brian A Newman