A multi-layer metal composite sheet with both high peel strength and force-electricity response and a preparation method thereof

Abstract

The present invention discloses a multi-layer metal composite sheet with both high peel strength and force-electric response and a preparation method thereof. The multi-layer metal composite sheet is composed of upper and lower metal substrates with ZnO nanorod arrays in-situ grown on the surface layers and a P(VDF-TrFE) layer disposed between the upper and lower metal substrates, and its piezoelectric properties are regulated by changing the density and aspect ratio of the ZnO nanorods. The multi-layer metal composite sheet with both high peel strength and force-electric response provided by the present invention has excellent overall force-electric response, and the P(VDF-TrFE) and the ZnO nanorod arrays have good interfacial bonding strength. The preparation method of the multi-layer metal composite sheet used in the present invention is simple and easy to implement.

Description

Technical Field

[0001] The present invention relates to the field of piezoelectric materials, and particularly to a multi-layer metal composite sheet with both high peel strength and force-electric response and a preparation method thereof. Background Art

[0002] Piezoelectric materials are materials that can induce electric charges when pressure is applied, and are functional materials that can realize the mutual conversion of electrical energy and mechanical energy. When a force is applied to a piezoelectric material without an electric field to cause deformation, electrical signals will appear on its surface. PVDF is a piezoelectric polymer with the largest piezoelectric performance, and has excellent flexibility, biocompatibility, mechanical strength and easy processing and molding, and is widely used in fields such as capacitors, triboelectric nanogenerators, sensors, and biological tissue repair. However, compared with traditional inorganic piezoelectric ceramic materials, the piezoelectric constant of the polymer PVDF is still relatively low. Therefore, improving the piezoelectric performance of the polymer PVDF film has become one of the current research hotspots at home and abroad, and one of the most used methods at present is to improve the piezoelectric performance of the polymer PVDF film by compounding inorganic piezoelectric ceramic particles.

[0003] ZnO is an inorganic piezoelectric ceramic material, which has good piezoelectric performance due to its unique asymmetric structure, and has important and wide applications in fields such as micro-nano electromechanical systems, biomedical medicine, micro-nano energy recycling and self-powered micro-nano systems. It has been reported to improve the piezoelectric performance of polymer PVDF films by compounding ZnO particles. Among them, a Chinese patent discloses a flaky ZnO-doped PVDF piezoresistive damping material and a preparation method thereof, which effectively improve its mechanical properties and piezoelectric performance [Shenyang University of Chemical Technology. A flaky ZnO-doped PVDF piezoresistive damping material and a preparation method thereof: CN201610819330.2 [P]. 2017-02-22]. However, when ZnO is introduced into the PVDF matrix, it is difficult for it to directly sense the external force and deform, which limits the improvement of its piezoelectric performance. Therefore, how to make the ZnO particles sense the external force and deform under the action of the external force to improve the piezoelectric performance of its composite with PVDF is a widely concerned issue. In order to compound ZnO with PVDF so that ZnO can sense the external force and deform, thereby improving its piezoelectric performance, a new structure for combining ZnO and PVDF needs to be constructed. Summary of the Invention

[0004] The object of the present invention is to provide a multi-layer metal composite sheet with both high peel strength and force-electricity response, and a preparation method thereof. The multi-layer metal composite sheet can control the piezoelectric properties by regulating the density and aspect ratio (the ratio of the average height to the average diameter of the nanorods) of ZnO nanorods. On the one hand, the multi-layer metal composite sheet of the present invention can greatly increase the content of the combination of ZnO and PVDF, improve its piezoelectric phase content, and avoid the influence of excessive volume of ZnO agglomeration on the piezoelectric properties; on the other hand, this new structure can directly make ZnO and PVDF feel the external force and deform simultaneously when the metal deforms, thereby improving its piezoelectric properties.

[0005] A multi-layer metal composite sheet with both high peel strength and force-electricity response is composed of upper and lower metal substrates with ZnO nanorod arrays (ZNR) grown in situ on the surface layer and a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) layer disposed between the upper and lower metal substrates. The ZnO nanorods are in a hexagonal wurtzite structure, with a density of 100 to 600 per μm 2 , and an aspect ratio of 1 to 50. When the metal substrate deforms under the action of an external force, the force can be transmitted to the ZnO nanorod array grown in situ on the metal substrate; in addition, since the ZnO nanorod array is located on the metal substrate, the P(VDF-TrFE) solution can infiltrate into the gaps between the ZnO nanorods and wrap the ZnO nanorods through the vacuum spin-coating method. Therefore, there is a better interfacial combination between the ZnO nanorod array and the P(VDF-TrFE) film, and they can deform simultaneously under the action of an external force, and accordingly, the piezoelectric properties of both can be synergistically exerted.

[0006] A preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response includes the following steps:

[0007] (1). First, prepare an ethanol solution with a concentration of 0.1 to 0.5 M of a zinc source and ethanolamine (the molar ratio of the two is 1:1). Prepare a ZnO nanodot seed layer on the metal substrate by the spin-coating method, and then heat-treat it in a muffle furnace at 400 to 700 °C for 0.5 to 2 h to obtain a ZnO nanodot thin film grown on the metal substrate;

[0008] (2). Prepare an aqueous solution with a concentration of 0.01 to 0.05 M of zinc nitrate and hexamethylenetetramine (the molar ratio of the two is 1:1) as a growth mother liquor, and prepare ZnO nanorods by the hydrothermal method: put the metal substrate with the ZnO nanodot thin film grown in situ into a reaction kettle, keep it at 80 to 120 °C for 1 to 6 h. After the reaction is completed, take out the metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain the metal substrate with the ZnO nanorod array grown in situ.

[0009] (3). Add P(VDF-TrFE) solid powder to N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. Prepare a P(VDF-TrFE) film on the metal substrate with in-situ grown ZnO nanorod arrays by vacuum spin coating method, and place it in an oven at 37 - 60 °C for 24 - 48 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / metal substrate;

[0010] (4). Compose two P(VDF-TrFE) film / ZnO nanorod array / metal substrates prepared in step (3) into a multi-layer metal composite sheet in a symmetric manner by hot pressing method, and heat-treat it in a muffle furnace at 160 - 240 °C for 0.5 - 2 h;

[0011] (5). Polarize the multi-layer metal composite sheet obtained in step (4) by contact polarization method to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 1 - 30 pC / N.

[0012] The zinc source mentioned above includes zinc acetate, zinc butyrate, etc.

[0013] The metal is tantalum, stainless steel, titanium, etc., with a thickness of 20 - 200 μm.

[0014] The preparation of the P(VDF-TrFE) film on the metal substrate with in-situ grown ZnO nanorod arrays by vacuum spin coating method is specifically as follows: Place the metal substrate with in-situ grown ZnO nanorod arrays in a sealed container with an internal pressure of 0.01 - 0.05 MPa, drop the P(VDF-TrFE) solution onto the metal substrate with in-situ grown ZnO nanorod arrays, and spin coat at a speed of 1000 - 4000 rpm on a spin coater for 20 - 40 s. In the multi-layer metal composite sheet, the thickness of the P(VDF-TrFE) film is 1 - 10 μm.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1). The ZnO nanorod arrays belong to in-situ growth. Compared with the method of spin coating or casting ZnO nanorod solution, the in-situ grown ZnO nanorod arrays are not easily agglomerated, and have a strong binding force with the metal substrate, and can withstand greater mechanical force and its deformation.

[0017] (2). The vacuum spin coating method can increase the specific surface area of contact between the ZnO nanorod arrays and P(VDF-TrFE), making the interface combination between the ZnO nanorod arrays and P(VDF-TrFE) on the upper and lower metal surfaces similar to mechanical occlusion, and the interface combination is stronger.

[0018] (3) Under the action of mechanical force, after the metal deforms, it conducts the force to the ZnO nanorod array, deforms simultaneously with P(VDF-TrFE), improves the piezoelectric performance, and greatly improves its overall force-electricity response.

[0019] A multi-layer metal composite sheet with both high peel strength and force-electricity response of the present invention combines ZnO nanorods with excellent piezoelectric performance and P(VDF-TrFE) with flexibility and good piezoelectric performance, enabling it to have both high peel strength and overall excellent force-electricity response. In addition, the preparation method of the present invention has a simple process and is easy to implement, which is conducive to popularization and application. The present invention composes the ZnO nanorod array on the metal surface layer with the PVDF film to form a multi-layer metal composite sheet with both high peel strength and excellent force-electricity response, which has strong practical application significance and research value in the field of piezoelectric materials. Brief Description of the Drawings

[0020] Figure 1 is a schematic diagram of the Ti / ZNR / P(VDF-TrFE) / ZNR / Ti multi-layer metal composite sheet;

[0021] Figure 2 is a cross-sectional SEM image of the Ti / ZNR / P(VDF-TrFE) / ZNR / Ti multi-layer metal composite sheet;

[0022] Figure 3 is a voltage-time graph of the Ti / ZNR / P(VDF-TrFE) / ZNR / Ti multi-layer metal composite sheet under the action of mechanical force. Detailed Embodiments

[0023] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0024] Example 1

[0025] (1) First, prepare an ethanol solution of zinc acetate and ethanolamine with the same molar amount and a concentration of 0.1M. Use a pipette to draw 10 μl of the precursor solution and spin-coat it on the titanium metal substrate at room temperature. The spin-coating speed is set to 4000 rpm, and the spin-coating time is 30 s. Then, heat-treat it in a muffle furnace at 400 °C for 0.5 h to obtain a ZnO nanodot film grown on a 20-μm titanium metal substrate;

[0026] (2) Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar amount and a concentration of 0.01M as the growth mother liquor. Take 40 mL and put it into a Telfon reaction kettle. Place the titanium metal substrate with the in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 80 °C for 1 h. After the reaction, take out the titanium metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a density of 100 pieces / μm 2, a titanium metal substrate with ZnO nanorod arrays having an aspect ratio of 2;

[0027] (3). Add P(VDF-TrFE) solid powder to N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.01 MPa, drop the P(VDF-TrFE) solution onto the titanium metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 1000 rpm for 20 s on a spin coater, and place it in an oven at 37 °C for 24 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / titanium metal substrate;

[0028] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) film / ZnO nanorod array / titanium metal substrates prepared in step (3), and heat-treat in a muffle furnace at 160 °C for 0.5 h to obtain a P(VDF-TrFE) film with a thickness of 1 μm;

[0029] (5). Use the contact polarization method to polarize the obtained multi-layer metal composite sheet to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 2 pC / N. After folding it 100 times repeatedly, no material peeling is found, and under the action of a mechanical force of 0.1 N, a voltage of 0.28 V is generated.

[0030] Example 2

[0031] (1). First, prepare an ethanol solution of zinc butoxide and ethanolamine with the same molar amount and a concentration of 0.2 M. Use a pipette to draw 15 μl of the precursor solution and spin-coat it on a tantalum metal substrate at room temperature. The spin-coating speed is set to 4500 rpm and the spin-coating time is 33 s. Then heat-treat in a muffle furnace at 450 °C for 1 h to obtain a ZnO nanodot film grown on a 25-μm tantalum metal substrate;

[0032] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar amount and a concentration of 0.02 M as the growth mother liquor. Take 50 mL and put it into a Telfon reaction kettle. Place the tantalum metal substrate with in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 85 °C for 1.5 h. After the reaction is completed, take out the tantalum metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a density of 150 pieces / μm 2 , a tantalum metal substrate with ZnO nanorod arrays having an aspect ratio of 5;

[0033] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.02 MPa, drop the P(VDF-TrFE) solution onto the tantalum metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 1200 rpm on a spin coater for 22 s, and place it in an oven at 40 °C for 28 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / tantalum metal substrate;

[0034] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) films / ZnO nanorod arrays / tantalum metal substrates prepared in step (3), and heat-treat it in a muffle furnace at 175 °C for 1 h to obtain a P(VDF-TrFE) film with a thickness of 2 μm;

[0035] (5). Polarize the above-obtained multi-layer metal composite sheet by the contact polarization method to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 5 pC / N. After folding it back and forth 100 times, no material peeling is found, and under the action of a mechanical force of 0.2 N, a voltage of 0.5 V is generated.

[0036] Example 3

[0037] (1). First, prepare an ethanol solution of zinc acetate and ethanolamine with the same molar amount and a concentration of 0.3 M. Use a pipette to draw 20 μl of the precursor solution and spin-coat it on a stainless steel metal substrate at room temperature. The spin-coating speed is set to 5000 rpm, and the spin-coating time is 37 s. Then heat-treat it in a muffle furnace at 500 °C for 1.5 h to obtain a ZnO nanodot film grown on a 50-μm stainless steel metal substrate;

[0038] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar amount and a concentration of 0.03 M as the growth mother liquor. Take 60 mL and put it into a Telfon reaction kettle. Place the stainless steel metal substrate with in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 90 °C for 2 h. After the reaction, take out the stainless steel metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a stainless steel metal substrate with ZnO nanorod arrays with a density of 150 per μm 2 , and an aspect ratio of 10;

[0039] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic waves until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.03 MPa, drop the P(VDF-TrFE) solution onto the stainless-steel metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 1500 rpm on a spin coater for 25 s, and place it in an oven at 45 °C for 30 h to obtain a P(VDF-TrFE) thin film / ZnO nanorod array / stainless-steel metal substrate;

[0040] (4). Compose two P(VDF-TrFE) thin film / ZnO nanorod array / stainless-steel metal substrates prepared in step (3) into a multi-layer metal composite sheet in a symmetric manner by hot pressing method, and heat-treat it in a muffle furnace at 180 °C for 1.5 h to obtain a P(VDF-TrFE) thin film with a thickness of 3 μm;

[0041] (5). Polarize the obtained multi-layer metal composite sheet by the contact polarization method to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 10 pC / N. After folding it back and forth 100 times, no material peeling is found, and under the action of a mechanical force of 0.3 N, a voltage of 0.76 V is generated.

[0042] Example 4

[0043] (1). First, prepare an ethanol solution of zinc butoxide and ethanolamine with the same molar concentration of 0.4 M. Use a pipette to aspirate 25 μl of the precursor solution, spin-coat it on the titanium metal substrate at room temperature, set the spin-coating speed to 5500 rpm, and the spin-coating time to 40 s. Then heat-treat it in a muffle furnace at 550 °C for 0.5 h to obtain a ZnO nanodot thin film grown on a 75-μm titanium metal substrate;

[0044] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar concentration of 0.04 M as the growth mother liquor. Take 65 mL and put it into a Telfon reaction kettle. Place the titanium metal substrate with in-situ grown ZnO nanodot thin film in the growth solution, then keep the reaction kettle at 95 °C for 2.5 h. After the reaction, take out the titanium metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a titanium metal substrate with ZnO nanorod arrays with a density of 200 per μm 2 , and an aspect ratio of 15;

[0045] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic waves until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.04 MPa, drop the P(VDF-TrFE) solution onto the titanium metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 1800 rpm on a spin coater for 27 s, and place it in an oven at 50 °C for 40 h to obtain a P(VDF-TrFE) thin film / ZnO nanorod array / titanium metal substrate;

[0046] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) thin film / ZnO nanorod array / titanium metal substrates prepared in step (3), and heat-treat it in a muffle furnace at 185 °C for 0.5 h to obtain a P(VDF-TrFE) thin film with a thickness of 4 μm;

[0047] (5). Use the contact electrode polarization method to polarize the obtained multi-layer metal composite sheet to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 15 pC / N. After folding it back and forth 100 times, no material peeling was found, and under the action of a mechanical force of 0.4 N, a voltage of 1.12 V was generated.

[0048] Example 5

[0049] (1). First, prepare an ethanol solution of zinc acetate and ethanolamine with the same molar amount and a concentration of 0.5 M. Use a pipette to draw 30 μl of the precursor solution and spin-coat it on the tantalum metal substrate at room temperature. The spin-coating speed is set to 6000 rpm, and the spin-coating time is 44 s. Then heat-treat it in a muffle furnace at 600 °C for 1 h to obtain a ZnO nanodot thin film grown on a 100-μm tantalum metal substrate;

[0050] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar amount and a concentration of 0.05 M as the growth mother liquor. Take 70 mL and put it into a Telfon reaction kettle. Place the tantalum metal substrate with in-situ grown ZnO nanodot thin film in the growth solution, and then keep the reaction kettle at 100 °C for 3 h. After the reaction is completed, take out the tantalum metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a tantalum metal substrate with in-situ grown ZnO nanorod arrays with a density of 250 per μm 2 , and an aspect ratio of 20;

[0051] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic waves until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.05 MPa, drop the P(VDF-TrFE) solution onto the tantalum metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 2500 rpm on a spin coater for 29 s, and place it in an oven at 55 °C for 42 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / tantalum metal substrate;

[0052] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) film / ZnO nanorod array / tantalum metal substrates prepared in step (3), and heat-treat it in a muffle furnace at 190 °C for 1 h to obtain a P(VDF-TrFE) film with a thickness of 5 μm;

[0053] (5). Use the contact polarization method to polarize the above-obtained multi-layer metal composite sheet to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 18 pC / N. After folding it back and forth 100 times, no material peeling was found, and under the action of a mechanical force of 0.5 N, a voltage of 1.45 V was generated.

[0054] Example 6

[0055] (1). First, prepare an ethanol solution with the same molar amount of 0.1 M zinc butoxide and ethanolamine. Use a pipette to draw 10 μl of the precursor solution and spin-coat it on a stainless steel metal substrate at room temperature. The spin-coating speed is set to 6500 rpm, and the spin-coating time is 45 s. Then heat-treat it in a muffle furnace at 650 °C for 1.5 h to obtain a ZnO nanodot film grown on a 125-μm stainless steel metal substrate;

[0056] (2). Prepare an aqueous solution with the same molar amount of 0.05 M zinc nitrate and hexamethylenetetramine as the growth mother liquor. Take 75 mL and put it into a Telfon reaction kettle. Place the stainless steel metal substrate with in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 105 °C for 4 h. After the reaction, take out the stainless steel metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a stainless steel metal substrate with a ZnO nanorod array with a density of 300 per μm 2 and an aspect ratio of 25;

[0057] (3). Add P(VDF-TrFE) solid powder into N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.01 MPa, drop the P(VDF-TrFE) solution onto the stainless-steel metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 2800 rpm on a spin coater for 32 s, and place it in an oven at 60 °C for 44 h to obtain a P(VDF-TrFE) film / ZnO nanorod arrays / stainless-steel metal substrate;

[0058] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) film / ZnO nanorod arrays / stainless-steel metal substrates prepared in step (3). Heat-treat it in a muffle furnace at 195 °C for 1.5 h to obtain a P(VDF-TrFE) film with a thickness of 6 μm;

[0059] (5). Use the contact electrode polarization method to polarize the obtained multi-layer metal composite sheet to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 22 pC / N. After repeatedly bending 100 times, no material peeling is found, and under the action of a mechanical force of 0.6 N, a voltage of 1.80 V is generated.

[0060] Example 7

[0061] (1). First, prepare an ethanol solution of zinc acetate and ethanolamine with the same molar amount and a concentration of 0.2 M. Use a pipette to aspirate 15 μl of the precursor solution and spin-coat it on a titanium metal substrate at room temperature. The spin-coating speed is set to 7000 rpm, and the spin-coating time is 46 s. Then heat-treat it in a muffle furnace at 700 °C for 0.5 h to obtain a ZnO nanodot film grown on a 150-μm titanium metal substrate;

[0062] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar amount and a concentration of 0.04 M as the growth mother liquor. Take 80 mL and put it into a Telfon reaction kettle. Place the titanium metal substrate with in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 110 °C for 5 h. After the reaction, take out the titanium metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a titanium metal substrate with ZnO nanorod arrays of 550 pieces / μm 2 , with an aspect ratio of 45;

[0063] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.02 MPa, drop the P(VDF-TrFE) solution onto the titanium metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 3200 rpm on a spin coater for 35 s, and place it in an oven at 48 °C for 46 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / titanium metal substrate;

[0064] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) film / ZnO nanorod array / titanium metal substrates prepared in step (3), and heat-treat it in a muffle furnace at 200 °C for 0.5 h to obtain a P(VDF-TrFE) film with a thickness of 7 μm;

[0065] (5). Use the contact polarization method to polarize the obtained multi-layer metal composite sheet to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 25 pC / N. After being bent back and forth 100 times, no material peeling was found, and under the action of a mechanical force of 0.7 N, a voltage of 1.86 V was generated.

[0066] Example 8

[0067] (1). First, prepare ethanol solutions of zinc butoxide and ethanolamine with the same molar concentration of 0.4 M. Use a pipette to draw 30 μl of the precursor solution and spin-coat it on the tantalum metal substrate at room temperature. The spin-coating speed is set at 7500 rpm, and the spin-coating time is 48 s. Then heat-treat it in a muffle furnace at 550 °C for 1 h to obtain a ZnO nanodot film grown on a 175-μm tantalum metal substrate;

[0068] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar concentration of 0.02 M as the growth mother liquor. Take 70 mL and put it into a Telfon reaction kettle. Place the tantalum metal substrate with in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 115 °C for 6 h. After the reaction, take out the tantalum metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a tantalum metal substrate with ZnO nanorod arrays of 600 pieces / μm 2 , with an aspect ratio of 40;

[0069] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.03 MPa, drop the P(VDF-TrFE) solution onto the tantalum metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 3500 rpm on a spin coater for 38 s, and place it in an oven at 42 °C for 48 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / tantalum metal substrate;

[0070] (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) film / ZnO nanorod array / tantalum metal substrates prepared in step (3), and heat-treat it in a muffle furnace at 205 °C for 1 h to obtain a P(VDF-TrFE) film with a thickness of 8 μm;

[0071] (5). Use the contact polarization method to polarize the obtained multi-layer metal composite sheet to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 28 pC / N. After folding it back and forth 100 times, no material peeling was found, and under the action of a mechanical force of 0.8 N, a voltage of 2.16 V was generated.

[0072] Example 9

[0073] (1). First, prepare an ethanol solution of zinc acetate and ethanolamine with the same molar concentration of 0.5 M. Use a pipette to draw 10 μl of the precursor solution and spin-coat it on the tantalum metal substrate at room temperature. The spin-coating speed is set to 8000 rpm, and the spin-coating time is 50 s. Then heat-treat it in a muffle furnace at 450 °C for 1.5 h to obtain a ZnO nanodot film grown on a 200-μm stainless steel metal substrate;

[0074] (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar concentration of 0.01 M as the growth mother liquor. Take 65 mL and put it into a Telfon reaction kettle. Place the stainless steel metal substrate with in-situ grown ZnO nanodot film in the growth solution, and then keep the reaction kettle at 120 °C for 2 h. After the reaction, take out the stainless steel metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a stainless steel metal substrate with ZnO nanorod arrays of 500 pieces / μm 2 , with an aspect ratio of 50;

[0075] (3). Add the P(VDF-TrFE) solid powder to the N,N-dimethylformamide (DMF) solvent, stir under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. In a closed container with an internal pressure of 0.04 MPa, drop the P(VDF-TrFE) solution onto the stainless steel metal substrate with in-situ grown ZnO nanorod arrays, spin-coat at a speed of 4000 rpm for 40 s on a spin coater, and place it in an oven at 45 °C for 48 h to obtain a P(VDF-TrFE) film / ZnO nanorod array / stainless steel metal substrate;

[0076] (4). Compose two P(VDF-TrFE) film / ZnO nanorod array / stainless steel metal substrates prepared in step (3) into a multi-layer metal composite sheet in a symmetric manner by hot pressing; heat-treat in a muffle furnace at 210 °C for 2 h to obtain a P(VDF-TrFE) film with a thickness of 10 μm;

[0077] (5). Polarize the obtained multi-layer metal composite sheet by the contact polarization method to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 30 pC / N. After bending it 100 times repeatedly, no material peeling is found. And under the action of a mechanical force of 0.9 N, a voltage of 2.89 V is generated. The piezoelectric coefficient is a proportionality constant that describes the linear response relationship between the mechanical quantity and the electrical quantity of a piezoelectric material. In Example 9, the ZnO nanorod array has a high density, a high content combined with P(VDF-TrFE), a high piezoelectric phase content, and a high aspect ratio of ZnO nanorods. As a nucleating agent, it can increase the piezoelectric phase content of P(VDF-TrFE), so its piezoelectric coefficient is also high. When subjected to a large mechanical force, the generated electrical quantity, that is, the voltage, is also high. In addition, when the ZnO nanorods with a high aspect ratio are subjected to a greater mechanical force, due to the deformation, the relative displacement between the centers of anions and cations in its crystal is also greater, that is, the dipole moment is greater. The superposition of all unit dipole moments forms a higher piezoelectric potential along the strain direction in the ZnO crystal.

Claims

1. A preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response, characterized in that, The multi-layer metal composite sheet is composed of upper and lower metal substrates with ZnO nanorod arrays in-situ grown on the surface layers and a P(VDF-TrFE) layer disposed between the upper and lower metal substrates. The ZnO nanorods are in a hexagonal wurtzite structure with a density of 100 to 600 per μm 2 , and the aspect ratio of the ZnO nanorods is 1 to 50; the preparation method comprises the following steps: (1). First, prepare ethanol solutions of zinc source and ethanolamine with the same molar amount and a concentration of 0.1 - 0.5 M. Then, use the spin-coating method to prepare a ZnO nanodot seed layer on a metal substrate. After that, heat-treat it in a muffle furnace at 400 - 700 °C for 0.5 - 2 h to obtain a ZnO nanodot thin film grown on the metal substrate. (2). Prepare an aqueous solution of zinc nitrate and hexamethylenetetramine with the same molar amount and a concentration of 0.01 - 0.05 M as the growth mother liquor, and prepare ZnO nanorods by hydrothermal method: Put the metal substrate with in-situ grown ZnO nanodot thin film into a reaction kettle, keep it at 80 - 120 °C for 1 - 6 h. After the reaction, take out the metal substrate, wash it with deionized water and ethanol respectively, and dry it to obtain a metal substrate with in-situ grown ZnO nanorod arrays. (3). Add P(VDF-TrFE) solid powder to N,N-dimethylformamide (DMF) solvent, stir it under ultrasonic until the powder is completely dissolved to obtain a P(VDF-TrFE) solution. Then, use the vacuum spin-coating method to prepare a P(VDF-TrFE) thin film on the metal substrate with in-situ grown ZnO nanorod arrays, and place it in an oven at 37 - 60 °C for 24 - 48 h to obtain a P(VDF-TrFE) thin film / ZnO nanorod array / metal substrate. (4). Use the hot pressing method to form a multi-layer metal composite sheet by symmetrically combining two P(VDF-TrFE) thin film / ZnO nanorod array / metal substrates prepared in step (3), and heat-treat it in a muffle furnace at 160 - 240 °C for 0.5 - 2 h. (5). Use the contact polarization method to polarize the multi-layer metal composite sheet obtained above to obtain a multi-layer metal composite sheet with a P(VDF-TrFE) piezoelectric coefficient of 1 - 30 pC / N.

2. The preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response according to claim 1, characterized in that, In step (1), the spin-coating speed is 4000 - 8000 rpm, and the spin-coating time is 30 - 50 s.

3. The preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response according to claim 1, characterized in that, The zinc source includes zinc acetate and butyl zincate.

4. The preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response according to claim 1, characterized in that, The material of the metal substrate includes tantalum, stainless steel, and titanium, and the thickness is 20 - 200 μm.

5. The preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response according to claim 1, characterized in that In step (3), use the vacuum spin-coating method to prepare a P(VDF-TrFE) thin film on the metal substrate with in-situ grown ZnO nanorod arrays. Specifically: Place the metal substrate with in-situ grown ZnO nanorod arrays in a sealed container with an internal pressure of 0.01 - 0.05 MPa, drop the P(VDF-TrFE) solution onto the metal substrate with in-situ grown ZnO nanorod arrays, and spin-coat it at a speed of 1000 - 4000 rpm for 20 - 40 s on a spin coater.

6. The preparation method of a multi-layer metal composite sheet with both high peel strength and force-electricity response according to claim 1, characterized in that, In the multi-layer metal composite sheet, the thickness of the P(VDF-TrFE) thin film is 1 - 10 μm.

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