阅读说明：本技术 一种柔性压电复合材料、柔性压电器件及其制备方法 (Flexible piezoelectric composite material, flexible piezoelectric device and preparation method thereof ) 是由 杨诚 陈超杰 于 2020-03-17 设计创作，主要内容包括：本发明公开了一种柔性压电复合材料、柔性压电器件及其制备方法,所述柔性压电复合材料的制备方法,包括：(1)将PVDF基聚合物、二维片层结构的Ti<Sub>3</Sub>C<Sub>2</Sub>T<Sub>x</Sub>材料、有机溶剂三者形成分散液,其中,PVDF基聚合物溶于有机溶剂得到PVDF基聚合物溶液,Ti<Sub>3</Sub>C<Sub>2</Sub>T<Sub>x</Sub>材料均匀分散在PVDF基聚合物溶液中,PVDF基聚合物溶液中,PVDF基聚合物浓度为1-25wt％,分散液中,Ti<Sub>3</Sub>C<Sub>2</Sub>T<Sub>x</Sub>材料相对于PVDF基聚合物的质量分数为0.001％～10％；(2)将分散液涂覆在基板上并使有机溶剂挥发后得到薄膜；(3)在极化场强≤150MV/m的高压电场下极化薄膜得到柔性压电复合材料薄膜,其具有较高含量的β相,压电性能有显著提高。(The invention discloses a flexible piezoelectric composite material, a flexible piezoelectric device and a preparation method thereof, wherein the preparation method of the flexible piezoelectric composite material comprises the following steps: (1) PVDF-based polymer, Ti with two-dimensional lamellar structure 3 C 2 T x The dispersion liquid is formed by the material and the organic solvent, wherein, PVDF-based polymer is dissolved in the organic solvent to obtain PVDF-based polymer solution, Ti 3 C 2 T x The material is uniformly dispersed in PVDF-based polymerIn the solution of PVDF-based polymer, the concentration of PVDF-based polymer in the solution is 1-25 wt%, and in the dispersion, Ti 3 C 2 T x The mass fraction of the material relative to PVDF-based polymer is 0.001% -10%, (2) a film is obtained by coating the dispersion liquid on a substrate and volatilizing an organic solvent, and (3) the film is polarized under a high-voltage electric field with the polarization field intensity less than or equal to 150MV/m to obtain the flexible piezoelectric composite material film which has higher β phase content and obviously improved piezoelectric performance.)

1. The preparation method of the flexible piezoelectric composite material is characterized by comprising the following steps of:

(1) polymerizing a PVDF-based polymerCompound, two-dimensional lamellar structure Ti₃C₂T_xThe dispersion liquid is formed by the material and the organic solvent, wherein the PVDF-based polymer is dissolved in the organic solvent to obtain a PVDF-based polymer solution, and the Ti₃C₂T_xUniformly dispersing a material in a PVDF-based polymer solution, wherein the mass concentration of the PVDF-based polymer in the PVDF-based polymer solution is 1-25%, and the Ti in the dispersion liquid₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10%;

(2) coating the dispersion liquid on a substrate and volatilizing the organic solvent to obtain a film;

(3) polarizing the film under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m to obtain PVDF-based/Ti₃C₂Tx flexible piezoelectric composite films.

2. The method of preparing a flexible piezoelectric composite material according to claim 1, wherein: the PVDF-based polymer includes at least one of PVDF and PVDF-based copolymers including P (VDF-TrFE), PVDF-HFP, P (VDF-CTFE), P (VDF-TrFE-CTFE).

3. The method of preparing a flexible piezoelectric composite material according to claim 1, wherein: the organic solvent is a polar solvent and comprises at least one of dimethylacetamide, N dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, diethylacetamide, trimethyl phosphate, triethyl phosphate, acetone, ammonium hexametaphosphate, chloroform and propylene carbonate.

4. The method for preparing a flexible piezoelectric composite material according to claim 1, wherein: in the PVDF-based polymer solution, the mass concentration of the PVDF-based polymer is 17-22%.

5. The method for preparing a flexible piezoelectric composite material according to claim 1, wherein: in the dispersion, Ti₃C₂T_xThe mass fraction of the PVDF-based polymer is 2-6%.

6. The method of preparing a flexible piezoelectric composite material according to claim 1, wherein: ti of the two-dimensional lamellar structure₃C₂T_xThe length of the sheet layer of the material is 10-10000 nm, the thickness is 1-100 nm, and the length-height ratio is less than or equal to 5000.

7. The method of preparing a flexible piezoelectric composite material according to claim 1, wherein: the polarization temperature in the step (3) is 30-90 ℃, and the polarization time is less than or equal to 12 h.

8. A flexible piezoelectric composite material produced by the production method according to any one of claims 1 to 7, wherein Ti is contained in the composite material₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10%.

9. A flexible piezoelectric device, prepared from the flexible piezoelectric composite material according to claim 8, comprising a flexible piezoelectric composite material film, electrode layers respectively disposed on the upper and lower surfaces of the flexible piezoelectric composite material film, and protective layers respectively disposed on the two electrode layers.

10. A method of manufacturing a flexible piezoelectric device according to claim 9, comprising the steps of:

(1) PVDF-based polymer, Ti with two-dimensional lamellar structure₃C₂T_xThe dispersion liquid is formed by the material and the organic solvent, wherein the PVDF-based polymer is dissolved in the organic solvent to obtain a PVDF-based polymer solution, and the Ti₃C₂T_xUniformly dispersing a material in a PVDF-based polymer solution, wherein the mass concentration of the PVDF-based polymer in the PVDF-based polymer solution is 1-25%, and the Ti in the dispersion liquid₃C₂T_xMass of material relative to the PVDF-based polymerThe fraction is 0.001 to 10 percent;

(2) coating the dispersion liquid on a substrate and volatilizing the organic solvent to obtain a film;

(3) polarizing the film under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m to obtain PVDF-based/Ti₃C₂The method comprises the following steps that a Tx flexible piezoelectric composite material film is prepared, electrode layers are respectively prepared on the upper surface and the lower surface of the flexible piezoelectric composite material film, and the flexible piezoelectric device is formed by packaging through a protective layer; or preparing an electrode layer on one surface of the film obtained in the step (2), polarizing under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m, preparing another electrode layer on the other surface, and finally packaging by using a protective layer to form the flexible piezoelectric device.

Technical Field

The invention relates to a piezoelectric material, in particular to a flexible piezoelectric composite material, a flexible piezoelectric device and a preparation method thereof.

Background

In recent years, wearable electronic equipment has been developed rapidly, and a flexible wearable pressure sensor is a most important ring in human-computer interaction, and is widely applied to the fields of pulse measurement, heart rate monitoring, touch feedback and the like.

In the preparation process of the PVDF film, the α phase is often converted into the β phase by means of corona polarization, thermal polarization and the like, and other methods also comprise post-treatment methods such as mechanical stretching, thermal treatment and the like, but the effects achieved by the treatment methods are limited.

Disclosure of Invention

In order to make up for the defects of the prior art, the invention provides a flexible piezoelectric composite material, a flexible piezoelectric device and a preparation method thereof.

The technical problem of the invention is solved by the following technical scheme:

a preparation method of a flexible piezoelectric composite material comprises the following steps:

(1) PVDF-based polymer, Ti with two-dimensional lamellar structure₃C₂T_xThe dispersion liquid is formed by the material and the organic solvent, wherein the PVDF-based polymer is dissolved in the organic solvent to obtain a PVDF-based polymer solution, and the Ti₃C₂T_xUniformly dispersing a material in a PVDF-based polymer solution, wherein the mass concentration of the PVDF-based polymer in the PVDF-based polymer solution is 1-25%, and the Ti in the dispersion liquid₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10%;

(2) coating the dispersion liquid on a substrate and volatilizing the organic solvent to obtain a film;

(3) polarizing the film under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m to obtain PVDF-based/Ti₃C₂Tx flexible piezoelectric composite films.

Preferably, the PVDF-based polymer includes at least one of PVDF and PVDF-based copolymers including P (VDF-TrFE), PVDF-HFP, P (VDF-CTFE), P (VDF-TrFE-CTFE).

Preferably, the organic solvent is a polar solvent including at least one of dimethylacetamide, N dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, diethylacetamide, trimethyl phosphate, triethyl phosphate, acetone, ammonium hexametaphosphate, chloroform, propylene carbonate.

Preferably, in the PVDF-based polymer solution, the mass concentration of the PVDF-based polymer is 17-22%.

Preferably, in the dispersion, Ti₃C₂T_xThe mass fraction of the PVDF-based polymer is 2-6%.

Preferably, Ti of the two-dimensional lamellar structure₃C₂T_xThe length of the sheet layer of the material is 10-10000 nm, the thickness is 1-100 nm, and the length-height ratio is less than or equal to 5000.

Preferably, the polarization temperature in the step (3) is 30-90 ℃, and the polarization time is less than or equal to 12 h.

The flexible piezoelectric composite material is prepared by the preparation method, wherein Ti₃C₂T_xPolymerization of materials relative to PVDF-basedThe mass fraction of the substance is 0.001-10%.

A flexible piezoelectric device is prepared from the flexible piezoelectric composite material and comprises a flexible piezoelectric composite material film, electrode layers respectively arranged on the upper surface and the lower surface of the flexible piezoelectric composite material film, and protective layers respectively arranged on the two electrode layers.

A method for preparing a flexible piezoelectric device comprises the following steps: (1) PVDF-based polymer, Ti with two-dimensional lamellar structure₃C₂T_xThe dispersion liquid is formed by the material and the organic solvent, wherein the PVDF-based polymer is dissolved in the organic solvent to obtain a PVDF-based polymer solution, and the Ti₃C₂T_xUniformly dispersing a material in a PVDF-based polymer solution, wherein the mass concentration of the PVDF-based polymer in the PVDF-based polymer solution is 1-25%, and the Ti in the dispersion liquid₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10%; (2) coating the dispersion liquid on a substrate and volatilizing the organic solvent to obtain a film; (3) polarizing the film under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m to obtain PVDF-based/Ti₃C₂The method comprises the following steps that a Tx flexible piezoelectric composite material film is prepared, electrode layers are respectively prepared on the upper surface and the lower surface of the flexible piezoelectric composite material film, and the flexible piezoelectric device is formed by packaging through a protective layer; or preparing an electrode layer on one surface of the film obtained in the step (2), polarizing under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m, preparing another electrode layer on the other surface, and finally packaging by using a protective layer to form the flexible piezoelectric device.

Compared with the prior art, the invention has the advantages that: the invention adds a specific amount of Ti₃C₂T_xIncorporated into PVDF-based polymers, Ti₃C₂T_xThe surface of the film is provided with rich surface functional groups which can form hydrogen bond action with PVDF-based polymer molecular chains to realize orientation arrangement of the PVDF molecular chains, and the finally formed flexible piezoelectric composite material film has high β phase content, so that the piezoelectric performance is remarkably improved, and the PVDF-based polymer is widened in the range of possible piezoelectric propertiesApplication in the field of wearable electronics.

Drawings

FIG. 1 is an open circuit voltage curve of embodiment 1 of the present invention;

FIG. 2 is an open circuit voltage curve of example 2 of the present invention;

FIG. 3 is an open circuit voltage curve of embodiment 3 of the present invention;

FIG. 4 is an open circuit voltage curve of embodiment 4 of the present invention;

FIG. 5 is an open circuit voltage curve of embodiment 5 of the present invention;

FIG. 6 is an open circuit voltage curve of comparative example 1;

fig. 7 is a schematic view of a flexible piezoelectric device produced by each of the examples of the present invention and comparative examples.

Detailed Description

The invention will be further described with reference to the accompanying drawings and preferred embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It should be noted that the terms of orientation such as left, right, up, down, top and bottom in the present embodiment are only relative concepts to each other or are referred to the normal use state of the product, and should not be considered as limiting.

The present invention may be understood by those skilled in the art by reference to the following detailed description taken in conjunction with the accompanying drawings, in which it is noted that the drawings depict only a portion of the display device and that, for the sake of clarity and conciseness of the drawings, certain elements of the drawings are not necessarily drawn to scale. In addition, the number and size of the elements in the drawings are merely illustrative and are not intended to limit the scope of the present invention.

It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or film, there are no intervening elements or films present between the two.

A preparation method of a flexible piezoelectric composite material comprises the following steps: (1) PVDF-based polymer, Ti with two-dimensional lamellar structure₃C₂T_xThe dispersion liquid is formed by the material and the organic solvent, wherein, PVDF-based polymer is dissolved in the organic solvent to obtain PVDF-based polymer solution, Ti₃C₂T_xThe material is uniformly dispersed in PVDF-based polymer solution, the mass concentration of the PVDF-based polymer in the PVDF-based polymer solution is 1-25%, and Ti in the dispersion liquid₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10 percent; (2) coating the dispersion on a substrate and volatilizing the organic solvent (for example, volatilizing the organic solvent by drying) to obtain a thin film; (3) polarizing the film under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m to obtain PVDF-based/Ti₃C₂Tx flexible piezoelectric composite films.

Wherein, Ti₃C₂T_xThe material can be uniformly dispersed in PVDF-based polymer solution by ultrasonic, and Ti₃C₂T_xT in the material_xReferred to as surface group O^2-、OH^-、F^-、NH₃、NH⁴⁺At least one of which is a polar functional group capable of forming a hydrogen bond with the molecular chain of the PVDF-based polymer. The dispersion liquid in the step (2) can be formed into a film by one or more of spin coating, scraper coating, screen printing, slit extrusion, micro-concave coating and steel plate printing, and the substrate can be a release film, engineering plastics, glass or metal foil.

In some preferred embodiments, the PVDF-based polymer comprises at least one of PVDF and PVDF-based copolymers, including but not limited to poly (vinylidene fluoride-trifluoroethylene) P (VDF-TrFE), polyvinylidene fluoride-hexafluoropropylene PVDF-HFP, poly (vinylidene fluoride-chlorotrifluoroethylene) P (VDF-CTFE), poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) P (VDF-TrFE-CTFE), and like PVDF-based copolymers.

In some preferred embodiments, the organic solvent is a polar solvent, including but not limited to at least one of dimethylacetamide (DMAc), N Dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), diethylacetamide (DEAc), trimethyl phosphate (TMP), triethyl phosphate (TEP), acetone, ammonium Hexametaphosphate (HMPA), chloroform, propylene carbonate, and the like.

In some preferred embodiments, the mass concentration of the PVDF-based polymer in the PVDF-based polymer solution is 17-22%.

In some preferred embodiments, in the dispersion, Ti₃C₂T_xThe mass fraction of the PVDF-based polymer is 2-6%.

In some preferred embodiments, the Ti of the two-dimensional lamellar structure₃C₂T_xThe length of the sheet layer of the material is 10-10000 nm, the thickness is 1-100 nm, and the aspect ratio (aspect ratio) is less than or equal to 5000.

In some preferred embodiments, the polarization temperature in step (3) is 30-90 ℃, the polarization time is less than or equal to 12h, and the polarization mode includes, but is not limited to, thermal polarization and corona polarization.

The flexible piezoelectric composite material is prepared by any preparation method, wherein Ti₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10%.

A flexible piezoelectric device is prepared from the flexible piezoelectric composite material and comprises a flexible piezoelectric composite material film, electrode layers respectively arranged on the upper surface and the lower surface of the flexible piezoelectric composite material film, and protective layers respectively arranged on the two electrode layers.

The flexible piezoelectric device is, for example, a flexible piezoelectric sensor.

A method for preparing a flexible piezoelectric device comprises the following steps: (1) PVDF-based polymer, Ti with two-dimensional lamellar structure₃C₂T_xThe dispersion liquid is formed by the material and the organic solvent, wherein, PVDF-based polymer is dissolved in the organic solvent to obtain PVDF-based polymer solution, Ti₃C₂T_xMaterial uniformityDispersed in a PVDF-based polymer solution in which the mass concentration of the PVDF-based polymer is 1 to 25%, and in which Ti is present in the dispersion₃C₂T_xThe mass fraction of the material relative to the PVDF-based polymer is 0.001-10 percent; (2) coating the dispersion liquid on a substrate and volatilizing the organic solvent to obtain a film; (3) polarizing the film under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m to obtain PVDF-based/Ti₃C₂The method comprises the following steps that a Tx flexible piezoelectric composite material film is prepared, electrode layers are respectively prepared on the upper surface and the lower surface of the flexible piezoelectric composite material film, and the flexible piezoelectric device is formed by packaging through a protective layer; or preparing an electrode layer on one surface of the film obtained in the step (2), polarizing under a high-voltage electric field with the polarization field intensity of less than or equal to 150MV/m, preparing another electrode layer on the other surface, and finally packaging by using a protective layer to form the flexible piezoelectric device.

The electrode layer can be prepared by conventional physical vapor deposition methods such as magnetron sputtering, multi-arc ion plating, thermal evaporation and the like, the electrode material comprises metals such as Au, Ag, Cu, Al, Ni, Fe, Ti and the like and alloy materials, and the thickness range is 100 nm-1000 nm. The material of the protective layer for encapsulation includes, but is not limited to, common polymer encapsulation materials such as polydimethylsiloxane PDMS, thermoplastic polyurethane TPU, epoxy resin, BT resin, polyimide PI, polyethylene terephthalate PET, and the like.

The invention is further illustrated by the following more specific examples.