An element including: a first electrode; an intermediate layer made of a silicone rubber composition containing a silicone rubber; and a second electrode, where the first electrode, the intermediate layer, and the second electrode are disposed in this order, wherein a peak intensity ratio (1095±5 cm.sup.−1/1025±5 cm.sup.−1) of an infrared absorption spectrum of the intermediate layer varies along a vertical direction relative to a surface of the first electrode, and to a surface of the second electrode.

Provided is an energy conversion film excellent in charge retention performance and suppressed in deterioration of piezoelectricity even if it is exposed to a high temperature environment and an energy conversion element and the like using the film. An energy conversion element comprising: an energy conversion film at least comprises a charged resin film consisting of a resin film at least containing a thermoplastic resin and a metal soap; and an electrode provided on at least one of the two surfaces of the energy conversion film.

An electret element includes: an electret film that contains silicon oxide; and a protective film formed over the electret film and constituted of aluminum oxide deposited through an atomic layer deposition method.

Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

An element includes an upper electrode, a flexible intermediate layer, and a lower electrode. The upper electrode having an uneven structure. The lower electrode is closely attached to the intermediate layer. The element is configured to generate an electrical signal due to contact and separation between the upper electrode and the intermediate layer. The lower electrode is configured to take a shape fittable to the uneven structure when the upper electrode and the intermediate layer come into contact with each other.

An electretized film of the present invention includes a cyclic olefin polymer, in which the electretized film is a non-porous film, and a piezoelectric constant d.sub.33 in a thickness direction, which is measured by applying a pressing force to the electretized film in the thickness direction, under conditions of a load of 0.5 N, a dynamic load of ±0.25 N, a frequency of 110 Hz, a temperature of 23° C., and a humidity of 50%, is equal to or more than 100 pC/N.

Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

This invention provides electrically conductive electret, electret-based direct-current power source and structural electret, with applications including the self-sensing of damage, stress and strain (including structural self-sensing) and electric powering (including structural self-powering). The electret is an electrically conductive material comprising mobile charge carriers (electrons, holes or ions), which exhibit a gradient in the carrier concertation along a line connecting the positive charge center and negative charge center in the electret. The carriers create an electric dipole. The material is electrically continuous along this line, which is along the path of least electrical resistance. The material exhibits microstructure comprising microscopic features that are positioned along said line and that interact with said carriers, with the interaction enhancing said dipole. The materials are preferably metals, carbons and their composites. The electret's electric field preferably ranges from 10′ V/m to 1 V/m. The electrical conductivity preferably ranges from 10.sup.3Ω.sup.−1.Math.m.sup.−1 to 10.sup.8Ω.sup.−1.Math.m.sup.−1.

An electret includes an electret layer. The electret layer is formed by subjecting a composite film in which inorganic dielectric particles are dispersed and held in a base film to a polarization treatment. The inorganic dielectric particles are mainly composed of an inorganic dielectric material having a bandgap energy of 4 eV or more.

A piezoelectric stack includes a porous resin sheet, and a surface coating layer disposed on an exterior surface of the porous resin sheet, the exterior surface including at least one of a front surface and a back surface of the porous resin sheet, the surface coating layer having a volume resistivity of not less than 1×10.sup.13 Ω.Math.cm, the porous resin sheet and the surface coating layer having different elastic moduli.