A stretchable pressure sensor based on metal single particles and preparation method thereof

Abstract

The present invention provides a stretchable pressure sensor based on a single metal particle and a preparation method thereof, belonging to the technical field of sensor devices. The stretchable pressure sensor based on a single metal particle obtained by the present invention comprises a first elastomer packaging layer, an intermediate elastomer support layer, and a second elastomer packaging layer; the intermediate elastomer support layer is provided with a cavity, and metal particles are implanted in the cavity; the first elastomer packaging layer is provided with a first electrode layer; the second elastomer packaging layer is provided with a second electrode layer; the first electrode layer is provided with a first ionized elastomer film, and the second electrode layer is provided with a second ionized elastomer film; the first ionized elastomer film and the second ionized elastomer film are in contact with the metal particles of the intermediate elastomer support layer, respectively. When in a stretched state, the pressure applied by the outside can also be accurately calculated by the change in capacitance value without being disturbed by the signal generated by the stretching.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensor devices, and in particular relates to a stretchable pressure sensor based on a metal single particle and a preparation method thereof. Background Art

[0002] Pressure sensors are sensors that can detect changes in external pressure and are widely used in wearable and attachable electronic devices. In recent years, with the development of flexible electronics, stretchable, flexible, transparent, attachable electronic devices have shown great application potential in the consumer electronics market, medical health, military and other industrial fields. Therefore, the requirements for performance indicators such as flexibility, accuracy, reliability, and sensitivity of pressure sensors are becoming increasingly higher, and traditional pressure sensors are often difficult to meet the above requirements. The research on using different materials to prepare new stretchable, flexible, transparent, attachable pressure sensors with simple structure, wide response range, high sensitivity, and good stability has attracted widespread attention from researchers at home and abroad, and has gradually become one of the important frontier research fields.

[0003] After continuous research, pressure sensors have made great progress in terms of high sensitivity, good linearity and wide detection range. Therefore, the demand for them in wearable electronic devices in the fields of disease monitoring, human-computer interaction and intelligent sensing is increasing. However, when faced with simultaneous stretch and pressure signals, the accuracy of the pressure signal of this type of sensor will be disturbed by the stretch state, and this problem has not been well solved. Although the capacitance value and the corresponding pressure reading can be corrected to a certain extent through methods such as strain isolation or capacitance compensation, pressure sensors that are intrinsically stretchable and can accurately measure pressure under stretch have not yet been realized. Summary of the invention

[0004] In view of this, the present invention aims to provide a stretchable pressure sensor based on a single metal particle and a preparation method thereof, which can accurately calculate the external pressure through the change of capacitance value when in a stretched state without being disturbed by the signal generated by the stretching.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a stretchable pressure sensor based on a metal single particle, comprising a first elastomer packaging layer, an intermediate elastomer support layer, and a second elastomer packaging layer;

[0007] The intermediate elastic body support layer is provided with a cavity, and metal particles are implanted in the cavity;

[0008] The first elastomer encapsulation layer is provided with a first electrode layer; the second elastomer encapsulation layer is provided with a second electrode layer; the first electrode layer is provided with a first ionizing elastomer film, and the second electrode layer is provided with a second ionizing elastomer film;

[0009] The first ionizing elastomer film and the second ionizing elastomer film are respectively in contact with the metal particles of the intermediate elastomer support layer.

[0010] The stretchable pressure sensor of the present invention is composed of a single metal particle with good conductivity and high elastic modulus, an upper and lower layer of an ionizing elastomer film with low elastic modulus, an intermediate support layer, and an upper and lower low elastic modulus elastomer encapsulation layer with an electrode layer. When external pressure is applied, the high elastic modulus metal particles will be embedded in the low elastic modulus ionizing elastomer, resulting in an increase in contact area, significantly increasing the double-layer capacitance value, and realizing pressure detection. When there is no external pressure, the contact area between the metal particles and the ionizing elastic film is extremely small, so its capacitance value is very small. In the stretched state, the encapsulation layer and the ionizing elastomer film are stretched and deformed, but the metal particles with high elastic modulus are not deformed. Therefore, in the non-stretched and stretched states, the contact area between the metal particles and the ionizing elastomer film is not affected by the stretched state, but only by the applied pressure.

[0011] Preferably, the thickness of the first elastomer encapsulation layer and the second elastomer encapsulation layer is 100-400 μm.

[0012] Preferably, the electrode layers of the first elastomer encapsulation layer and the second elastomer encapsulation layer are provided by magnetron sputtering or scraping conductive dielectrics. In the present invention, the electrode material is a flexible and stretchable conductive material, and the stretchable electrode material can be selected from commercially available materials.

[0013] More preferably, the electrode layer raw material is nanoparticles, nanosheets, nanowires, graphene, MXene, carbon nanotubes, and conductive polymers; and the nanoparticles, nanosheets, and nanowires are made of gold, silver, and copper.

[0014] Preferably, it is characterized in that the material of the first elastomer encapsulation layer, the intermediate elastomer support layer and the second elastomer encapsulation layer is a low modulus flexible elastomer; the elastic modulus of the low modulus flexible elastomer is 0.1-1.0 MPa.

[0015] Preferably, the low modulus flexible elastomer is a biodegradable plastic or a thermoplastic rubber.

[0016] The upper and lower layers of low elastic modulus ionizing elastomer films can be flexible and stretchable polymer materials, which have the characteristics of being stretchable after drying, having good adhesion to the electrode layer substrate, and not being easy to fall off in a stretched state.

[0017] Preferably, the diameter of the metal particles is the same as the thickness of the intermediate elastic support layer; the diameter of the metal particles is the same as the diameter of the cavity. The cavity is located in the middle of the intermediate elastic support layer, and a metal particle is implanted in the cavity; a hole equivalent to the diameter of a single metal particle needs to be drilled in the middle of the intermediate elastic support layer, and the metal particle is implanted therein to play a role of fixing and supporting.

[0018] Preferably, the metal particles have a particle size of 50-500 μm and are spherical particles.

[0019] Preferably, the metal particles are conductive metal particles.

[0020] More preferably, the material of the metal particles includes but is not limited to copper, iron, and nickel.

[0021] Preferably, the ionizing elastomer film is formed by mixing a polyurethane elastomer and an ionic liquid in a mass ratio of 1:0.1-1 and then coating the mixture.

[0022] The present invention also provides a method for preparing the above-mentioned stretchable pressure sensor, comprising the following steps: assembling the layers by plasma cleaning or the like to obtain the stretchable pressure sensor.

[0023] Contains at least the following beneficial technical effects:

[0024] 1) The low elastic modulus encapsulation layer and the ionizing elastomer film of the present invention are stretched and deformed, but the metal particles with high elastic modulus are not deformed. Therefore, in the non-stretched and stretched states, the contact area between the metal particles and the ionizing elastomer film is not affected by the stretched state, but only by the applied pressure. Therefore, even if the pressure sensor is in a stretched state, the external pressure can be accurately calculated by the change in capacitance value without being disturbed by the signal generated by the stretching.

[0025] 2) The pressure sensor has high sensitivity under low pressure conditions and a large detection range. When stress is applied, its response and recovery time are fast. When stretched, the pressure response is independent of the stretching, and the maximum stretching ratio can reach 50%

[0026] 3) The pressure sensor has the advantages of simple preparation method, common materials, low cost and good sensing performance. Therefore, its application in health monitoring, human-computer interaction, electronic skin and other fields is further expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A cross-sectional view of the pressure sensor.

[0028] Figure 2 A top view of the pressure sensor.

[0029] Figure 3 Bending diagram of the pressure sensor.

[0030] Figure 4 This is the capacitance-pressure response diagram under small pressure of Example 1.

[0031] Figure 5 This is the capacitance-pressure response diagram under high pressure of Example 1.

[0032] Figure 6 This is a diagram of the sensor response and recovery time of Example 1.

[0033] Figure 7 This is a graph showing the response of the sensor of Example 1 to capacitance under different stretching conditions. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0036] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the main idea or essential features of the present invention. Therefore, from all points of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0037] In addition, it should be understood that although this specification is described according to the implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. These other implementation modes are also covered within the protection scope of the present invention.

[0038] It should also be understood that the specific embodiments described above are only used to explain the present invention, and the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the protection scope of the present invention / invention.

[0039] Example 1

[0040] This embodiment provides a stretchable pressure sensor based on a metal single particle, comprising a first elastomer packaging layer, an intermediate elastomer support layer, and a second elastomer packaging layer; the material of each layer is polydimethylsiloxane with an elastic modulus of 0.5 MPa;

[0041] The thickness of the first elastomer packaging layer and the second elastomer packaging layer is 200 μm; the first elastomer packaging layer is provided with a first electrode layer; the second elastomer packaging layer is provided with a second electrode layer; the electrode layers of the first elastomer packaging layer and the second elastomer packaging layer are respectively provided by magnetron sputtering or scraping conductive dielectrics, and the raw material of the electrode layers used is silver nanoparticles.

[0042] The first electrode layer is provided with a first ionizing elastomer film, and the second electrode layer is provided with a second ionizing elastomer film; the ionizing elastomer film is formed by mixing a polyurethane elastomer and 35% 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt ionic liquid in a mass ratio of 1:1 and then coating the mixture;

[0043] The thickness of the middle elastic support layer is 100 μm, and a cavity with a diameter of 100 μm is set in the center, and a copper metal spherical particle with a particle size of 100 μm is implanted in the cavity;

[0044] The first ionizing elastomer film and the second ionizing elastomer film are respectively in contact with the metal particles of the intermediate elastomer support layer.

[0045] The first elastomer packaging layer, the middle elastomer supporting layer and the second elastomer packaging layer are assembled by plasma cleaning to obtain a stretchable pressure sensor.

[0046] Example 2

[0047] This embodiment provides a stretchable pressure sensor based on a metal single particle, comprising a first elastomer packaging layer, an intermediate elastomer support layer, and a second elastomer packaging layer; the material of each layer is polydimethylsiloxane with an elastic modulus of 0.1 MPa;

[0048] The thickness of the first elastomer packaging layer and the second elastomer packaging layer is 100 μm; the first elastomer packaging layer is provided with a first electrode layer; the second elastomer packaging layer is provided with a second electrode layer; the electrode layers of the first elastomer packaging layer and the second elastomer packaging layer are respectively arranged by magnetron sputtering or scraping a conductive dielectric, and the raw material of the electrode layer used is carbon nanotubes.

[0049] The first electrode layer is provided with a first ionizing elastomer film, and the second electrode layer is provided with a second ionizing elastomer film; the ionizing elastomer film is formed by mixing a polyurethane elastomer and 20% 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt ionic liquid in a mass ratio of 1:0.1 and then coating the mixture;

[0050] The thickness of the middle elastic support layer is 50 μm, and a cavity with a diameter of 50 μm is set in the center, and a copper metal spherical particle with a particle size of 50 μm is implanted in the cavity;

[0051] The first ionizing elastomer film and the second ionizing elastomer film are respectively in contact with the metal particles of the intermediate elastomer support layer.

[0052] The first elastomer packaging layer, the middle elastomer supporting layer and the second elastomer packaging layer are assembled by plasma cleaning to obtain a stretchable pressure sensor.

[0053] Example 3

[0054] This embodiment provides a stretchable pressure sensor based on a metal single particle, comprising a first elastomer packaging layer, an intermediate elastomer support layer, and a second elastomer packaging layer; the material of each layer is Ecoflex (purchased from Smooth-On, USA) with an elastic modulus of 1.0 MPa;

[0055] The thickness of the first elastomer packaging layer and the second elastomer packaging layer is 400 μm; the first elastomer packaging layer is provided with a first electrode layer; the second elastomer packaging layer is provided with a second electrode layer; the electrode layers of the first elastomer packaging layer and the second elastomer packaging layer are respectively provided by magnetron sputtering or scraping a conductive dielectric, and the raw material of the electrode layer used is silver nanosheets.

[0056] The first electrode layer is provided with a first ionizing elastomer film, and the second electrode layer is provided with a second ionizing elastomer film; the ionizing elastomer film is formed by mixing a polyurethane elastomer and 50% 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt ionic liquid in a mass ratio of 1:0.5 and then coating the mixture;

[0057] The thickness of the middle elastic support layer is 500 μm, and a cavity with a diameter of 500 μm is set in the center, and a copper metal spherical particle with a particle size of 500 μm is implanted in the cavity;

[0058] The first ionizing elastomer film and the second ionizing elastomer film are respectively in contact with the metal particles of the intermediate elastomer support layer.

[0059] The first elastomer packaging layer, the middle elastomer supporting layer and the second elastomer packaging layer are assembled by plasma cleaning to obtain a stretchable pressure sensor.

[0060] Test Example 1

[0061] By using the pressure sensor prepared in Example 1 and applying a certain pressure to the stretchable pressure sensor using a linear motor, the capacitance response graph under different pressures can be obtained. Figure 4 and 5 It can be seen that the sensor has high sensitivity and wide detection range under small pressure.

[0062] Test Example 2

[0063] The response and recovery diagram of the pressure sensor prepared in Example 1 is obtained by applying pressure to the sensor using a weight of a certain mass and calculating its response and recovery time. Figure 6 The excellent response and recovery time of the sensor can be seen.

[0064] Test Example 3

[0065] The pressure sensor prepared in Example 1 is used, a certain stretching ratio is given to the sensor, and then a linear motor is used to apply different pressures to the sensor to obtain the response of the capacitance to pressure under different stretching ratios. Figure 7 It can be obtained that under different stretching conditions, the capacitance change of the stretching sensor is only related to the applied pressure and has nothing to do with the stretching ratio.

[0066] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A stretchable pressure sensor based on a single metal particle, characterized in that: It includes a first elastomer packaging layer, an intermediate elastomer supporting layer, and a second elastomer packaging layer; The intermediate elastic body support layer is provided with a cavity, and metal particles are implanted in the cavity; The first elastomer encapsulation layer is provided with a first electrode layer; the second elastomer encapsulation layer is provided with a second electrode layer; the first electrode layer is provided with a first ionizing elastomer film, and the second electrode layer is provided with a second ionizing elastomer film; The first ionizing elastomer film and the second ionizing elastomer film are respectively in contact with metal particles of the intermediate elastomer support layer; The ionizing elastomer film is formed by mixing a polyurethane elastomer and an ionic liquid in a mass ratio of 1:0.1-1 and then coating the mixture.

2. The stretchable pressure sensor according to claim 1, characterized in that: The thickness of the first elastomer encapsulation layer and the second elastomer encapsulation layer is 100-400 μm.

3. The stretchable pressure sensor according to claim 2, characterized in that: The electrode layers of the first elastomer encapsulation layer and the second elastomer encapsulation layer are respectively provided by magnetron sputtering or scraping a conductive dielectric.

4. The stretchable pressure sensor according to any one of claims 1 to 3, characterized in that: The material of the first elastomer packaging layer, the middle elastomer supporting layer and the second elastomer packaging layer is a low modulus flexible elastomer; the elastic modulus of the low modulus flexible elastomer is 0.1-1.0 MPa.

5. The stretchable pressure sensor according to claim 4, characterized in that: The low modulus flexible elastomer is biodegradable plastic or thermoplastic rubber.

6. The stretchable pressure sensor according to claim 1, characterized in that: The particle size of the metal particles is the same as the thickness of the intermediate elastic body support layer; the particle size of the metal particles is the same as the diameter of the cavity.

7. The stretchable pressure sensor according to claim 6, characterized in that: The metal particles have a particle size of 50-500 μm and are spherical particles.

8. The stretchable pressure sensor according to claim 6, characterized in that: The metal particles are conductive metal particles.

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