JP5926903B2 - Method for producing a polymer having a desired Curie temperature - Google Patents

Description

  The present invention relates to a method for producing a polymer, and more particularly to a method for producing a polymer having a desired Curie temperature.

  The Curie temperature (also referred to as the Curie point) refers to a transition temperature at which a ferromagnetic material changes to a paramagnetic material, or a transition temperature at which a ferroelectric material changes to a paraelectric material.

  As an invention related to the Curie temperature, Patent Document 1 discloses an image recording method using potential decay when a charged ferroelectric polymer substance is heated, particularly an image that can be used for copying, printing, a printer, and the like. The recording method is described. Specifically, an image recording medium in which an image recording layer mainly composed of a ferroelectric polymer substance is provided on a conductive support is used. After the image recording layer is charged to a coercive electric field or more, an electrostatic latent image is formed by heating corresponding to the image, and each process such as toner development, transfer, and fixing is performed. At this time, the heating temperature for forming the electrostatic latent image is set to be equal to or lower than the Curie temperature of the ferroelectric polymer substance contained in the image recording layer. (Patent Document 1, (2), page 3, line 3, lines 19 to 31).

  When the image recording medium is charged, in the untreated state, the potential rise to the surface potential corresponding to the coercive electric field of the ferroelectric polymer substance is poor. However, when the coercive electric field is reached and the polarization becomes uniform (corresponding to the poling process), the rise of the surface potential becomes faster (so-called two-stage phenomenon, Patent Document 1, FIG. 3). After charging, when the temperature is raised below the Curie temperature, the surface potential is immediately attenuated to 0V. When charged again, the two-stage phenomenon does not occur at the rise of the surface potential, and the rise is fast (Patent Document 1, FIG. 4).

  As described above, the image recording method described in Patent Document 1 uses the rising speed of the surface potential after the ferroelectric polymer substance is charged more than the coercive electric field. After charging, the heating for forming an electrostatic latent image on the ferroelectric polymer material (image recording layer) must be not more than the Curie temperature. That is, the temperature range that can be heated is determined by the Curie temperature of the ferroelectric polymer substance. When heated to a temperature equal to or higher than the Curie temperature after charging, a two-stage phenomenon appears as in the untreated state (Patent Document 1, (2), page 4, line 14, line 14, FIG. 5).

  The Curie temperature is defined as the temperature at which the ferroelectricity erases, and is determined by the temperature dispersion of the dielectric constant (Patent Document 1, (2) page, 4 rows, 29 lines). When the ferroelectric polymer material is a homopolymer, the Curie temperature is set to a temperature unique to the polymer material. In the case of a copolymer, the Curie temperature is determined by the blending ratio of the monomers constituting the copolymer, and the Curie temperature after polymerization cannot be changed. That is, in the invention described in Patent Document 1, when a copolymer is used as the ferroelectric polymer substance, the heatable temperature range can be freely selected by changing the blending ratio during polymerization. . FIG. 1 of Patent Document 1 describes the Curie temperature when the composition (molar ratio) of a copolymer of vinylidene fluoride and trifluoroethylene (P (VDF / TrFE)) is changed (inflection point). Is the Curie temperature).

Japanese Patent No. 3027591

Thus, the Curie temperature of the copolymer is determined by the compounding ratio of the monomers when polymerizing the copolymer, and the Curie temperature of the copolymer cannot be changed after polymerization. Therefore, in order to obtain a ferroelectric polymer material of a copolymer having a desired Curie temperature, it is necessary to copolymerize monomers at a specific blending ratio each time, which requires labor and time.
Then, an object of this invention is to provide the method which can manufacture the polymer which has a desired Curie temperature easily from a copolymer.

The method for producing a polymer according to the first aspect of the present invention for solving the above-described problem is a method for producing a polymer having a desired Curie temperature as shown in FIG. 1, for example. Making the copolymer having a solution or melt (S01); a monomer constituting the copolymer being the same as the copolymer having the first Curie temperature, and a second Curie temperature different from the first Curie temperature; Making the copolymer having a solution or melt (S02); after dissolving or melting, mixing the copolymer having the first Curie temperature and the copolymer having the second Curie temperature to form a polymer blend ( S03, S04); a copolymer having the first Curie temperature and a copoly having the second Curie temperature The mixing ratio of over, the Curie temperature of the mixed polymer (polymer blend) is determined for a single temperature.
The “solution” refers to a liquid mixture composed of two or more substances. For example, solvent and solute. The “melt” refers to a substance having fluidity including a liquid state.

  If comprised in this way, the polymer which has single Curie temperature can be obtained only by mixing the copolymers from which Curie temperature differs. Furthermore, the Curie temperature of the polymer obtained by mixing correlates with the mixing ratio at the time of mixing. Therefore, by adjusting the mixing ratio when the copolymer is mixed, a polymer having a desired Curie temperature can be obtained without polymerization.

  The method for producing a polymer according to the second aspect of the present invention is the method for producing a polymer according to the first aspect of the present invention, wherein the copolymer is a copolymer composed of vinylidene fluoride and ethylene trifluoride.

  If comprised in this way, the copolymer (P (VDF / TrFE)) of the vinylidene fluoride-trifluoride ethylene which has desired Curie temperature can be obtained easily.

  The method for producing a ferroelectric film according to the third aspect of the present invention includes a step of forming the polymer produced by the method for producing a polymer according to the first aspect or the second aspect of the present invention into a film shape. Is provided.

  If comprised in this way, the ferroelectric film which has desired Curie temperature can be manufactured, without passing through the process of copolymerizing a monomer.

  The method for producing a piezoelectric / pyroelectric film according to the fourth aspect of the present invention comprises forming the polymer produced by the polymer production method according to the first aspect or the second aspect of the present invention into a film shape. And a step of polarizing the polymer formed into a film.

  If comprised in this way, the film provided with the piezoelectricity / pyroelectricity which has desired Curie temperature can be manufactured, without passing through the process of copolymerizing a monomer. Since the Curie temperature is a temperature at which piezoelectricity and pyroelectricity are lost, the heat resistance of the film can be improved by easily controlling the Curie temperature.

  A polymer PTC element according to a fifth aspect of the present invention is a film having a conductive filler dispersed in a polymer produced by the method for producing a polymer according to the first aspect or the second aspect of the present invention. And two electrode plates sandwiching the film-like polymer.

  If comprised in this way, the polymer PTC element provided with the polymer which has a desired Curie temperature can be manufactured, without passing through the process of copolymerizing a monomer.

  A ferroelectric capacitor according to a sixth aspect of the present invention comprises an insulating polymer produced by the polymer production method according to the first aspect or the second aspect of the present invention and formed into a film; And two electrode plates sandwiching the film-like polymer.

  If comprised in this way, the ferroelectric capacitor provided with the polymer which has a desired Curie temperature can be manufactured, without passing through the process of copolymerizing a monomer.

  A ferroelectric memory according to a seventh aspect of the present invention includes the ferroelectric capacitor according to the sixth aspect of the present invention; a word line and a bit line wired in a lattice pattern.

  If comprised in this way, a ferroelectric memory can be manufactured using the ferroelectric capacitor provided with the polymer which has a desired Curie temperature, without passing through the process of copolymerizing a monomer.

  According to the present invention, it is possible to easily produce a polymer having a desired Curie temperature. Further, by using the polymer, a ferroelectric film or a piezoelectric / pyroelectric film having a desired Curie temperature can be easily obtained. Can be manufactured. Furthermore, a polymer PTC element having a desired Curie temperature, a ferroelectric capacitor, and a ferroelectric memory can be easily manufactured using the polymer.

It is a flowchart which shows the manufacturing method of the polymer which concerns on the 1st Embodiment of this invention. It is a conceptual diagram of the apparatus 10 which polarizes a film. It is a figure which illustrates a ferroelectric memory circuit. 2 is a table showing the Curie temperature Tc of Copolymer A and Copolymer B and the Curie temperature Tc of a polymer produced by mixing Copolymer A and Copolymer B. It is a graph in which the horizontal axis represents the mixing ratio (% by weight) of copolymer B and the vertical axis represents the Curie temperature (° C.). 4 is a table showing Curie temperature Tc and melting point Tm of copolymer A and copolymer C, and Curie temperature Tc and melting point Tm of a polymer produced by mixing copolymer A and copolymer C. It is a graph which shows the change accompanying the heat balance of the measurement sample with respect to a temperature change by differential scanning calorimetry (DSC). It is a graph in which the horizontal axis represents the mixing ratio (% by weight) of copolymer C, and the vertical axis represents the Curie temperature (° C.). The horizontal axis indicates the contents of vinylidene fluoride (VDF) in the copolymer A, B, C, the polymer in which the copolymer A and the copolymer B are mixed, and the polymer in which the copolymer A and the copolymer C are mixed, and the vertical axis indicates the Curie. It is a graph made into temperature (degreeC).

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same or similar reference numerals, and redundant description is omitted. Further, the present invention is not limited to the following embodiment.

  In general, when polymers having different Curie temperatures are mixed together, the polymer blend will show the respective Curie temperatures that the mixed polymers had. However, the inventors have found that when polymers having different Curie temperatures are mixed, the polymer blend may result in a polymer having only one Curie temperature. Furthermore, the Curie temperature correlates with the mixing ratio of the polymer to be mixed, and it has been found that a polymer having a desired Curie temperature can be obtained by adjusting the mixing ratio, thereby completing the present invention.

With reference to FIG. 1, the manufacturing method of the polymer which concerns on the 1st Embodiment of this invention is demonstrated. As a polymer, a copolymer of vinylidene fluoride (C ₂ H ₂ F ₂ , VDF) and ethylene trifluoride (C ₂ HF ₃ , TrFE) (vinylidene fluoride-trifluoride ethylene copolymer: P (VDF / TrFE)) ).

  First, copolymers (copolymers) of vinylidene fluoride and ethylene trifluoride having different blending ratios during polymerization are prepared. Hereinafter, copolymers having different blending ratios during polymerization will be described as copolymer X and copolymer Y. Copolymer X and copolymer Y have different Curie temperatures due to different blending ratios during polymerization. In addition, a well-known method can be used for superposition | polymerization. For example, methods such as suspension polymerization, emulsion polymerization, and solution polymerization can be employed. However, aqueous suspension polymerization and emulsion polymerization are preferable from the viewpoint of ease of post-treatment, and aqueous suspension polymerization is particularly preferable.

  In suspension polymerization using water as a dispersion medium, a suspending agent such as methyl cellulose, methoxylated methyl cellulose, propoxylated methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyethylene oxide, and gelatin is added to 0.005 with respect to water. It is used by adding in the range of -1.0% by weight, preferably 0.01-0.4% by weight.

  As polymerization initiators, diisopropyl peroxydicarbonate, dinormalpropyl peroxydicarbonate, dinormalheptafluoropropyl peroxydicarbonate, isobutyryl peroxide, di (chlorofluoroacyl) peroxide, di (perfluoroacyl) Peroxide, tertiary butyl peroxypivalate, etc. can be used. The amount used is 0.1 to 5% by weight, preferably 0.5 to 2% by weight, based on the total amount of monomers (total amount of vinylidene fluoride and ethylene trifluoride).

  Adding a chain transfer agent such as ethyl acetate, methyl acetate, acetone, ethanol, n-propanol, acetaldehyde, propyl aldehyde, ethyl propionate, carbon tetrachloride, diethyl carbonate, etc. to adjust the degree of polymerization of the resulting polymer Is also possible. The amount used is usually 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the total amount of monomers.

  The total amount of monomers charged is 1: 1 to 1:10, preferably 1: 2 to 1: 5, in a weight ratio of the total amount of monomer to water. The polymerization is carried out at a temperature of 10 to 80 ° C. for 5 to 100 hours. Thus, vinylidene fluoride (VDF) and ethylene trifluoride (TrFE) can be copolymerized by suspension polymerization. In addition, the arrangement | sequence of the copolymer to produce | generate may be a random copolymer and an alternating copolymer, and in the case of a block copolymer and a graft copolymer, what has a smaller repeating number is preferable. Further, the copolymer X and the copolymer Y to be mixed may be copolymers having the same sequence or different copolymers.

Copolymer X and copolymer Y have different Curie temperatures due to different blending ratios during polymerization. Using the copolymer X and the copolymer Y having different Curie temperatures, as shown in FIG. 1, a polymer having a desired Curie temperature is produced by the following method.
S01: Copolymer _X and _{(P (VDF x / TrFE 100} -x)) were dissolved in N as the solvent, N- dimethylformamide (DMF), and the solution X. In addition, x and 100-x represent the compounding ratio (weight%) at the time of superposition | polymerization of VDF and TrFE, respectively.
S02: Copolymer _Y a _{(P (VDF y / TrFE 100} -y)) were dissolved in N as the solvent, N- dimethylformamide (DMF), and the solution Y. In addition, y and 100-y represent the compounding ratio (weight%) at the time of superposition | polymerization of VDF and TrFE, respectively, and x ≠ y.
S03: The solution X and the solution Y are mixed to obtain a mixed solution.
S04 / S05: Molded into a film using a solution casting method. That is, the mixed solution is poured into a drum (casting drum) having a smooth surface, and is heated to evaporate the solvent, and the resulting polymer (polymer blend) is formed into a film. The thickness of the film is appropriately selected according to the application. For example, it is formed into a film having a thickness of 1 to 500 μm.

  In addition to N, N-dimethylformamide (DMF), polar solvents such as methyl ethyl ketone (MEK), tetrahydrofuran (THF), N, N-dimethylacetamide (DMA), acetone, diethyl carbonate (DEC) are used as the solvent. May be. In addition, these solvents may be used alone or in combination of two or more of these solvents.

  The copolymer X and Y may be mixed after being melted instead of the solution. If it is a melt, the step of removing the solvent can be omitted. Furthermore, in addition to the above solution casting method, a spin coating method or a melt extrusion method may be used. For example, copolymer X and copolymer Y are supplied to a kneader such as a single screw extruder, twin screw extruder, Banbury mixer, roll mill, kneader, etc., melt kneaded, and the polymer blend is pelletized and formed into a film. May be. Alternatively, the copolymer X pellets and the copolymer Y pellets may be mixed well in advance using a mixer, and the polymer blend may be fed to a single screw extruder and extruded and cooled directly as a film or the like. By using the melt extrusion method, a film having a thickness of about 5 μm to 2 mm can be obtained.

  When copolymer X and copolymer Y having different Curie temperatures are mixed, the polymer (polymer blend) has one Curie temperature that is a temperature between the Curie temperature of copolymer X and the Curie temperature of copolymer Y. Furthermore, as will be described later in Examples, the Curie temperature of this polymer blend changed depending on the mixing ratio at the time of mixing, and showed a correlation with the mixing ratio. Therefore, if the temperature is between the Curie temperature of the copolymer X and the Curie temperature of the copolymer Y, a polymer having a desired Curie temperature can be easily obtained by selectively changing the mixing ratio of the copolymer X and the copolymer Y. it can. That is, according to the method for producing a polymer of the present invention, a polymer having a desired Curie temperature can be produced by mixing already produced copolymers without producing them from polymerization. Furthermore, a ferroelectric film having a desired Curie temperature can be easily obtained by forming this polymer into a film.

  A method for manufacturing the piezoelectric / pyroelectric film according to the second embodiment of the present invention will be described. In the second embodiment, the polymer manufactured by the polymer manufacturing method according to the first embodiment is formed into a film and then subjected to polarization treatment. For the polarization treatment, a known method can be used. For example, a polarization device 10 shown in FIG. 2 may be used as an example of a device that performs polarization processing. The apparatus 10 includes a flat metal plate 12 for fixing the film 1 cut to an appropriate size, and a non-contact needle electrode 11 (at least one) disposed above the film 1. During the polarization process, the metal plate 12 functions as a counter electrode of the needle electrode 11. Further, the needle electrode 11 and the metal plate 12 are connected via a DC high-voltage power supply 13. Specifically, for example, a film having a thickness of 50 μm is cut into a size of 10 cm × 10 cm, fixed on the metal plate 12 of the apparatus 10 shown in FIG. A DC voltage Vp of 10 to 15 (-kV) is applied. During the polarization treatment, it is preferable to heat the metal plate 12 using a heater (not shown) so that the temperature of the metal plate 12 (that is, the film 1) is 110 ° C. A film having piezoelectricity and pyroelectricity can be obtained by subjecting the film-like polymer produced by the polymer production method according to the first embodiment to polarization treatment.

  The polymer PTC element according to the third embodiment of the present invention is a film in which a conductive filler is dispersed in a polymer produced by the method for producing a polymer according to the first embodiment, and the polymer containing the filler is formed into a film. And formed by sandwiching the film between two electrode plates (metal foil such as platinum). As the conductive filler, carbon black, carbon fiber, or metal powder such as nickel powder can be used. The polymer PTC element may be a chip-type element or may be an element with a lead wire by welding a mounting lead to an electrode plate.

  The ferroelectric capacitor according to the fourth embodiment of the present invention includes a film-like polymer manufactured by the polymer manufacturing method according to the first embodiment, and two electrode plates sandwiching the film ( A metal foil such as platinum). Further, a ferroelectric memory may be configured using this ferroelectric capacitor. The ferroelectric memory may be a 1T type (FIG. 3A) including the ferroelectric capacitor 21, the word line 26, and the bit line 27 of the present invention, for example, as in the circuit shown in FIG. Furthermore, in addition to the ferroelectric capacitor 21, the word line 26, and the bit line 27, a 1T1C type (FIG. 3B) or 2T2C type (FIG. 3C) provided with a transistor 22 and a plate line 28. (T: transistor, C: capacitor). Further, the ferroelectric capacitor of the present invention may be used in circuits such as a ferroelectric latch, a ferroelectric SRAM, and a ferroelectric gate FET.

The copolymer P (VDF / TrFE) of vinylidene fluoride and ethylene trifluoride was copolymerized at the following blending ratio (vinylidene fluoride / ethylene trifluoride). The unit of the compounding ratio is% by weight. In addition, Curie temperature (Tc) is shown about each copolymer.
Copolymer A = 75/25, Tc: 118 ° C.
Copolymer B = 78/22, Tc: 128 ° C.
Copolymer C = 80/20, Tc: 137 ° C.

FIG. 4 shows the Curie temperature Tc of the copolymer A and the copolymer B, and the Curie temperature Tc of the polymer (polymer blend) produced by mixing the copolymer A and the copolymer B. The polymer blends were prepared by dissolving each in dimethylformamide (DMF) at the mixing ratio (% by weight) shown in FIG. 4 and mixing this solution, followed by drying at 40 ° C. for 2 to 48 hours to remove the solvent. Incidentally, when the presence of dry N ₂ or dry air (air) as the air flow, it is possible to increase the drying efficiency preferable.

The polymer blend produced by mixing had one Curie temperature. Furthermore, the Curie temperature exists between the Curie temperature of Copolymer A (118 ° C.) and the Curie temperature of Copolymer B (128 ° C.), and varied depending on the mixing ratio.
FIG. 5 shows a graph in which the horizontal axis represents the mixing ratio (% by weight) of copolymer B and the vertical axis represents the Curie temperature (° C.). As the graph of FIG. 5 shows, the Curie temperature of the polymer blend increased as the content of copolymer B having a higher Curie temperature increased. Furthermore, there is a clear correlation between the copolymer B content and the Curie temperature. In particular, when the copolymer B is 30 to 100% by weight, the Curie temperature rises almost linearly with respect to the content of the copolymer B. Accordingly, a polymer having a desired Curie temperature between the Curie temperature of Copolymer A and the Curie temperature of Copolymer B can be easily obtained by selectively changing the mixing ratio of Copolymer A and Copolymer B.

FIG. 6 shows the Curie temperature Tc and the melting point Tm of the copolymer A and the copolymer C, and the Curie temperature Tc and the melting point Tm of the polymer (polymer blend) produced by mixing the copolymer A and the copolymer C. The polymer blends were prepared by dissolving each in dimethylformamide (DMF) at the mixing ratio (% by weight) shown in FIG. 6 and mixing this solution, followed by drying at 40 ° C. for 48 hours to remove the solvent.
In FIG. 6, as in FIG. 4, the polymer blend produced by mixing had one Curie temperature. Furthermore, the Curie temperature exists between the Curie temperature of Copolymer A (118 ° C.) and the Curie temperature of Copolymer C (137 ° C.), and varied depending on the mixing ratio.

The graph in FIG. 7 is obtained by measuring a change with a heat balance of a measurement sample with respect to a temperature change by differential scanning calorimetry (DSC). The horizontal axis is temperature, and the vertical axis is heat flow. The measurement sample is a polymer (polymer blend) produced by mixing copolymer A and copolymer C and copolymer A and copolymer C shown in FIG.
Two trough peaks indicating endothermic reaction are shown. The small peak indicates the transition point from the ferroelectric phase to the paraelectric phase (Curie point, Tc), and the large peak indicates the transition point from the paraelectric phase to the molten phase. (Melting point, Tm).
As the graph of FIG. 7 shows, when copolymer A and copolymer C having different Curie temperatures are mixed, as the content of copolymer C having a high Curie temperature increases, the Curie temperature of the polymer blend increases and approaches the Curie temperature of copolymer C. I went.

  FIG. 8 is a graph in which the horizontal axis represents the mixing ratio (% by weight) of copolymer C and the vertical axis represents the Curie temperature (° C.). In the graph of FIG. 8, as in the graph of FIG. 5, there is a clear correlation between the content of the copolymer C and the Curie temperature. That is, as the content of the copolymer C increases, the Curie temperature increases almost linearly and approaches the Curie temperature of the copolymer C.

In FIG. 9, the horizontal axis represents the content of vinylidene fluoride (VDF) (mol%) in the copolymer A, B, C, the polymer blend of copolymer A and copolymer B, and the polymer blend of copolymer A and copolymer C, and the vertical axis. Is a graph with the Curie temperature (° C.). The alphabets A, B, and C in FIG. 9 indicate the copolymer A, the copolymer B, and the copolymer C, respectively. The diamonds on the line connecting A and B indicate a polymer (polymer blend) in which the polymer A and the polymer B are mixed. □ indicates a polymer (polymer blend) in which polymer A and polymer C are mixed.
When A, □, and C are connected on the graph of FIG. 9, the line segments almost overlap with the line connecting A, ◆, and B. This suggests that even when two copolymers of any polymerization ratio are selected and blended, the Curie temperature is determined by the ratio of vinylidene fluoride contained (or the ratio of ethylene trifluoride). To do.

DESCRIPTION OF SYMBOLS 1 Film 10 Apparatus 11 Needle electrode 12 Metal plate 13 DC high voltage power supply 21 Ferroelectric capacitor 22 Transistor 26 Word line 27 Bit line 28 Plate line

Claims (4)

A method for producing a polymer having a desired Curie temperature, comprising:
A step of a copolymer having a first Curie temperature melt,
It is the same as the copolymer monomers constituting the copolymer has a first Curie temperature, a step of the melt copolymers having different second Curie temperature than the first Curie temperature,
After melting, mixing the copolymer having the first Curie temperature and the copolymer having the second Curie temperature to produce a polymer blend ,
The mixing ratio of the copolymer having the first Curie temperature and the copolymer having the second Curie temperature determines the Curie temperature of the mixed polymer (polymer blend) to be a single temperature,
The copolymer is a copolymer composed of vinylidene fluoride and ethylene trifluoride.
A method for producing a polymer;
Molding the polymer produced by the polymer production method into a film;
A step of polarizing the polymer formed into a film;
The single Curie temperature varies linearly with the content of vinylidene fluoride constituting the copolymer having the first Curie temperature and the copolymer having the second Curie temperature;
The vinylidene fluoride content is 75 to 80% by weight based on the total amount of the copolymer,
The single Curie temperature is 118-137 ° C.
A method for producing a piezoelectric / pyroelectric film. A polymer blend having a desired Curie temperature,
A copolymer having a first Curie temperature;
A monomer constituting the copolymer is the same as the copolymer having the first Curie temperature and has a second Curie temperature different from the first Curie temperature;
The polymer blend has a single Curie temperature due to the mixing ratio of the copolymer having the first Curie temperature and the copolymer having the second Curie temperature;
The copolymer is a copolymer composed of vinylidene fluoride and ethylene trifluoride,
The single Curie temperature varies linearly with the content of vinylidene fluoride constituting the copolymer having the first Curie temperature and the copolymer having the second Curie temperature;
The vinylidene fluoride content is 75 to 80% by weight based on the total amount of the copolymer,
The single Curie temperature is 118-137 ° C.
Polymer blend. Polarized, comprising the polymer blend of claim 2
Piezoelectric / pyroelectric film. A piezoelectric / pyroelectric film according to claim 3;
Two electrode plates sandwiching the film;
Piezoelectric and pyroelectric elements.

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