Abstract: An object of the present invention is to provide a polarized vinylidene fluoride/tetrafluoroethylene copolymer resin film that can significantly reduce, when used as an optical film, the deterioration of the quality of video or still images formed by display elements. The present invention provides a polarized vinylidene fluoride/tetrafluoroethylene copolymer resin film having 2,000 or fewer spot defects per m2, the number of spot defects being measured by a defect measurement method; the method using an surface inspection system in which a CCD camera is placed so as to detect defects at an angle of 45 degrees relative to an LED source, defects of the film are read within a rectangular range of 300 mm in a width direction (the direction perpendicular to the scanning direction), and 150 mm in a machine direction (the scanning direction), while the film is scanned under the camera at a rate of 20 m/min; wherein first, defects having a bright area of 1.5 mm2 or less and a dark area of 1.

Abstract: A transparent piezoelectric sheet-with-a-frame includes a transparent piezoelectric sheet and a frame covering a peripheral edge portion of the transparent piezoelectric sheet. The transparent piezoelectric sheet includes one transparent piezoelectric film including an organic polymer, one first transparent plate electrode placed on a first main surface of the transparent piezoelectric film and having a first transparent plate electrode portion, and one second transparent plate electrode placed on a second main surface of the transparent piezoelectric film and having a second transparent plate electrode portion. An outline of the second transparent plate electrode portion is positioned inside an outline of the first transparent plate electrode portion as seen in a plan view. The outline of the first transparent plate electrode portion completely coincides with the frame, and the outline of the second transparent plate electrode portion does not at all coincide with the frame as seen in the plan view.

Abstract: A transparent piezoelectric sheet includes a quadrilateral-shaped transparent piezoelectric film and a first transparent plate electrode. The quadrilateral-shaped transparent piezoelectric film includes an organic polymer. The quadrilateral-shaped transparent piezoelectric film has entire main surfaces that are piezoelectric. The first transparent plate electrode is layered on part of a first main surface of the main surfaces of the transparent piezoelectric film. One to three sides of the four sides of the quadrilateral shape of the transparent piezoelectric film and area(s) of the first main surface adjacent thereto are not covered by the first transparent plate electrode.

Abstract: A vinylidene fluoride homopolymer represented by the formula (4): CF3-(A1)-I??(4) wherein A1 represents a structural unit of vinylidene fluoride homopolymer which includes crystal form I alone or as main component and has a number average degree of polymerization of 5 to 12.

Abstract: A hydrophobic dielectric film for electrowetting, which can drive a conductive liquid by using a low voltage and containing a vinylidene fluoride based polymer.

Abstract: A vinylidene fluoride homopolymer represented by the formula (4): CF3-(A1)—I??(4) wherein A1 represents a structural unit of vinylidene fluoride homopolymer which includes crystal form I alone or as main component and has a number average degree of polymerization of 5 to 12.

Abstract: There is provided a method of forming a thin film of vinylidene fluoride homopolymer having crystal form I which is applicable to various substrates in relatively easy way (coating conditions, application method, etc.), a process for preparing a vinylidene fluoride homopolymer having crystal form I efficiently at high purity, and novel vinylidene fluoride homopolymers which can give a thin film being excellent in ferroelectricity. The method of forming a thin film of vinylidene fluoride homopolymer comprises (i) a step for preparing a green powder product of vinylidene fluoride homopolymer comprising crystal form I alone or as main component by subjecting vinylidene fluoride to radical polymerization in the presence of a bromine compound or iodine compound having 1 to 20 carbon atoms which contains at least one moiety represented by —CRf1Rf2X1, wherein X1. is iodine atom or bromine atom; Rf1. and Rf2.

Abstract: A transparent piezoelectric sheet includes a quadrilateral-shaped transparent piezoelectric film and a first transparent plate electrode. The quadrilateral-shaped transparent piezoelectric film includes an organic polymer. The quadrilateral-shaped transparent piezoelectric film has entire main surfaces that are piezoelectric. The first transparent plate electrode is layered on part of a first main surface of the main surfaces of the transparent piezoelectric film. One to three sides of the four sides of the quadrilateral shape of the transparent piezoelectric film and area(s) of the first main surface adjacent thereto are not covered by the first transparent plate electrode.

Abstract: A transparent piezoelectric sheet-with-a-frame includes a transparent piezoelectric sheet and a frame covering a peripheral edge portion of the transparent piezoelectric sheet. The transparent piezoelectric sheet includes one transparent piezoelectric film including an organic polymer, one first transparent plate electrode placed on a first main surface of the transparent piezoelectric film and having a first transparent plate electrode portion, and one second transparent plate electrode placed on a second main surface of the transparent piezoelectric film and having a second transparent plate electrode portion. An outline of the second transparent plate electrode portion is positioned inside an outline of the first transparent plate electrode portion as seen in a plan view. The outline of the first transparent plate electrode portion completely coincides with the frame, and the outline of the second transparent plate electrode portion does not at all coincide with the frame as seen in the plan view.

Abstract: The present invention provides a process for easily preparing a vinylidene fluoride homopolymer comprising an I-form crystal structure at high purity by selecting a solvent, and the process for preparing the vinylidene fluoride homopolymer comprises not less than 70% by mass of I-form crystal structure, which is obtained by dissolving a vinylidene fluoride homopolymer having a number average degree of polymerization of 3 to 20 in a solvent consisting of an organic solvent having a dipole moment of not less than 2.8 alone or comprising the organic solvent in a part, thereafter, evaporating the solvent.

Abstract: The present invention provides a process for easily preparing a vinylidene fluoride homopolymer comprising an I-form crystal structure at high purity by selecting a solvent, and the process for preparing the vinylidene fluoride homopolymer comprises not less than 70% by mass of I-form crystal structure, which is obtained by dissolving a vinylidene fluoride homopolymer having a number average degree of polymerization of 3 to 20 in a solvent consisting of an organic solvent having a dipole moment of not less than 2.8 alone or comprising the organic solvent in a part, thereafter, evaporating the solvent.

Abstract: The present invention provides a process for easily preparing a vinylidene fluoride homopolymer comprising an I-form crystal structure at high purity by selecting a solvent, and the process for preparing the vinylidene fluoride homopolymer comprises not less than 70% by mass of I-form crystal structure, which is obtained by dissolving a vinylidene fluoride homopolymer having a number average degree of polymerization of 3 to 20 in a solvent consisting of an organic solvent having a dipole moment of not less than 2.8 alone or comprising the organic solvent in a part, thereafter, evaporating the solvent.

Abstract: There is provided a method of forming a thin film of vinylidene fluoride homopolymer having crystal form I which is applicable to various substrates in relatively easy way (coating conditions, application method, etc.), a process for preparing a vinylidene fluoride homopolymer having crystal form I efficiently at high purity, and novel vinylidene fluoride homopolymers which can give a thin film being excellent in ferroelectricity.

Abstract: There is provided a method of forming a thin film of vinylidene fluoride homopolymer having crystal form I which is applicable to various substrates in relatively easy way (coating conditions, application method, etc.), a process for preparing a vinylidene fluoride homopolymer having crystal form I efficiently at high purity, and novel vinylidene fluoride homopolymers which can give a thin film being excellent in ferroelectricity.

Abstract: The present invention provides a process for easily preparing a vinylidene fluoride homopolymer comprising an I-form crystal structure at high purity by selecting a solvent, and the process for preparing the vinylidene fluoride homopolymer comprises not less than 70% by mass of I-form crystal structure, which is obtained by dissolving a vinylidene fluoride homopolymer having a number average degree of polymerization of 3 to 20 in a solvent consisting of an organic solvent having a dipole moment of not less than 2.8 alone or comprising the organic solvent in a part, thereafter, evaporating the solvent.

Abstract: A method of forming a ferroelectric thin film containing vinylidene fluoride homopolymer, including the steps of (i) preparing a green powder of vinylidene fluoride homopolymer of crystal form I alone or as main component by subjecting vinylidene fluoride to radical polymerization in the presence of a radical polymerization initiator, (ii) forming a thin film on a substrate surface by using vinylidene fluoride homopolymer of crystal form I alone or as main component obtained from the green powder product of vinylidene fluoride homopolymer of I-form crystal structure alone or as main component, and (iii) subjecting the thin film of vinylidene fluoride homopolymer formed in step (ii) above to polarization.

Abstract: There is provided a pyroelectric infrared sensor being capable of changing its shape and having high sensitivity. The sensor comprises the substrate 11 made of a polymer material such as polyimide or polyethylene terephthalate and having flexibility, the layer 13 comprising vinylidene fluoride (VDF), and the flexible electrodes 12 and 14 comprising an Al-deposited film and provided on and under the VDF oligomer layer 13. The pyroelectric infrared sensor of the present invention has flexibility as a whole due to flexibility of each component elements and can be formed into desired shapes. In addition, since a substrate made of a polymer material has heat capacity and heat conductivity lower than those of Si substrates used on conventional pyroelectric infrared sensors, sensitivity of the sensor can be increased.

Abstract: There is provided a method of forming a ferroelectric thin film of vinylidene fluoride homopolymer having crystal form I which is applicable to various substrates in relatively easy way (coating conditions, application method, etc.). The method of forming a ferroelectric thin film comprising vinylidene fluoride homopolymer comprises the step (i) for preparing a green powder of vinylidene fluoride homopolymer comprising crystal form I alone or as main component by subjecting vinylidene fluoride to radical polymerization in the presence of a radical polymerization initiator, the step (ii) for forming a thin film on a substrate surface by using vinylidene fluoride homopolymer which comprises crystal form I alone or as main component and is obtained from the green powder product of vinylidene fluoride homopolymer comprising I-form crystal structure alone or as main component, and the step (iii) for subjecting the thin film of vinylidene fluoride homopolymer formed in the step of above (ii) to polarization.

Abstract: There is provided the method of forming a thin film of vinylidene fluoride homopolymer of I-form crystal structure having functional group at its end which can be applied to various substrates, by relatively easy method (applying conditions, manner, etc.). The method is a method of forming a thin film of vinylidene fluoride homopolymer by applying, on a substrate, a vinylidene fluoride homopolymer which contains, at one end or both ends thereof, a moiety represented by the formula (1): —(R1)n—Y??(1) wherein R1 is a divalent organic group but does not contain a structural unit of the vinylidene fluoride homopolymer; n is 0 or 1; Y is a functional group, and has from 3 to 100 repeat units of vinylidene fluoride, to form a thin film of vinylidene fluoride homopolymer comprising I-form crystal structure alone or as main component.

Abstract: There is provided a method of forming a fine pattern by using a practicable fluorine-containing polymer which has a high transparency to exposure light having a short wavelength such as F2 laser and can undergo resolution of a fine pattern.