CN114383761B - Pressure sensor with unidirectional conductive function and preparation method and application thereof - Google Patents
Pressure sensor with unidirectional conductive function and preparation method and application thereof Download PDFInfo
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/16—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in the magnetic properties of material resulting from the application of stress
Abstract
The invention relates to the technical field of sensors, and particularly discloses a pressure sensor with a unidirectional conductive function, and a preparation method and application thereof. The pressure sensor includes: two layers of flexible electrodes and a dielectric layer positioned between the two layers of flexible electrodes; the dielectric layer comprises a matrix material and magnetic conductive fibers distributed in the matrix material, and the magnetic conductive fibers are arranged in an orientation perpendicular to the flexible electrode. The pressure sensor provided by the invention has the advantages of flexibility, high sensitivity and wide monitoring range.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a pressure sensor with a unidirectional conductive function, and a preparation method and application thereof.
Background
The real-time accurate measurement of important information of human body by using the electronic sensor plays an important role in health monitoring and medical care, and the human skin can naturally distinguish pressure and various mechanical stimuli or mechanical deformations and perform independent sensing, so that the wearable electronic sensor device also has high-sensitivity sensing on the capability of various mechanical stresses. However, most of the current sensors rely on the change of contact resistance to realize pressure sensing, the deformation range is small, and high sensitivity and wide monitoring range cannot be realized.
Thus, the preparation of pressure sensors with high sensitivity and wide monitoring range remains a hot spot pursued in the sensor field.
Disclosure of Invention
The invention aims to overcome the technical problems in the prior art and provides a pressure sensor with a unidirectional conductive function, and a preparation method and application thereof.
In order to achieve the above object, a first aspect of the present invention provides a pressure sensor having a unidirectional electrical conduction function, the pressure sensor comprising: two layers of flexible electrodes and a dielectric layer positioned between the two layers of flexible electrodes; the dielectric layer comprises a matrix material and magnetic conductive fibers distributed in the matrix material, and the magnetic conductive fibers are arranged in an orientation perpendicular to the flexible electrode.
A second aspect of the present invention provides a method of manufacturing a pressure sensor having a unidirectional electrical conductivity function, the method comprising the steps of:
the magnetic conductive fibers are directionally distributed in the matrix material, and the flexible electrode is assembled;
wherein the magnetic conductive fibers are aligned perpendicular to the flexible electrode orientation.
The third aspect of the invention provides a pressure sensor prepared by the method.
A fourth aspect of the invention provides the use of the aforementioned pressure sensor in the field of wearable devices and/or human-computer interactions.
A fifth aspect of the invention provides a wearable device comprising the aforementioned pressure sensor.
The pressure sensor provided by the invention has the advantages of flexibility, high sensitivity and wide monitoring range.
Drawings
FIG. 1 is a schematic illustration of a magnetically conductive fiber after alignment according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of a sensor according to an embodiment of the present invention as a function of pressure;
in fig. 3, (a) is a graph showing the change of the ratio of real-time current to initial current according to the pressure change of the sensors prepared in example 1, example 4 and comparative example 1, respectively, according to the present invention at different pressures; (b) The sensors prepared in example 1, example 2 and example 3 of the present invention are graphs of the ratio of real-time current to initial current as pressure changes at different pressures; (c) The sensor prepared in example 1 was in a pressureless state with respect to current versus voltage (voltammogram) at different voltages; (d) Is a graph of the change of real-time current pressure change at different pressures of a sensor (example 1) according to an embodiment of the present invention; (e) The pressure sensor is a current diagram of the pressure sensor in the specific embodiment of the invention with different frequencies at the same pressure; (f) Is a change curve of real-time current of a sensor (example 1) according to an embodiment of the present invention under pressure stimulation; (g) Is a real-time current change curve of a sensor (example 1) according to an embodiment of the present invention under 3000 stimulations at the same pressure.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
A first aspect of the present invention provides a pressure sensor having a unidirectional electrical conductivity function, the pressure sensor comprising: two layers of flexible electrodes and a dielectric layer positioned between the two layers of flexible electrodes; the dielectric layer comprises a matrix material and magnetic conductive fibers distributed in the matrix material, and the magnetic conductive fibers are arranged in an orientation perpendicular to the flexible electrode.
According to some embodiments of the invention, the weight ratio of the base material to the magnetically conductive fibers may be (3-25): 1 (e.g., 3:1, 4:1, 5:1, 10:1, 15:1, 20:1, 25:1, or any value therebetween).
According to some embodiments of the invention, the magnetically conductive fibers may be cylindrical.
Preferably, the length of the magnetic conductive fiber is 0.5-3mm, and the diameter is 0.1-0.3mm.
According to some embodiments of the invention, the magnetic conductive fiber may have an electrical conductivity of (1.5-2) x 10 -3 Omega cm; the magnetic permeability can be (8-9) x 10 3 H/m。
According to some embodiments of the present invention, the magnetically conductive fibers may be selected from at least one of nickel plated carbon fibers, nickel plated metal fibers, nickel plated stainless steel, iron plated carbon fibers, and cobalt plated carbon fibers, preferably nickel plated carbon fibers and/or cobalt plated carbon fibers.
The thickness of the dielectric layer is not particularly limited as long as it can meet the requirements of the present invention, and for example, the thickness of the dielectric layer may be 2mm to 5mm.
According to some embodiments of the invention, the substrate material may be selected from a thermally curable material and/or a photo-curable material.
In the invention, the heat conductivity coefficient of the substrate material can be 0.134-0.159W/M K, the light transmittance can be 95-100%, and the substrate material has physiological inertia and good chemical stability. Wherein, the substrate material has electrical insulation property, weather resistance and shearing resistance and can be used for a long time at the temperature of-50 ℃ to 200 ℃.
According to some embodiments of the invention, the thermally curable material may be selected from polydimethylsiloxane and/or silica gel.
According to some embodiments of the invention, the photocurable material may be a photosensitive polyurethane.
According to some embodiments of the invention, the thickness of the two layers of flexible electrodes may each independently be 20 μm to 70 μm.
According to some embodiments of the invention, the flexible electrode may be selected from an interdigital electrode and/or a conductive metal electrode.
According to some embodiments of the invention, the upper electrode of the pressure sensor is a conductive metal electrode and the lower electrode is an interdigital electrode.
According to some embodiments of the invention, the number of pairs of interdigitated electrodes is 8-20.
According to some embodiments of the invention, the inter-digital line widths and line pitches of the inter-digital electrodes are each independently 100-200 μm.
According to a preferred embodiment of the invention, the interdigital electrode is prepared by magnetron sputtering, wherein the time of the magnetron sputtering is 20-40min.
According to a preferred embodiment of the invention, the magnetron sputtering is such that the metal deposited on the interdigitated electrodes has a thickness of 70-100nm. Preferably, the deposited metal is selected from copper and/or gold, preferably copper.
According to some embodiments of the invention, the conductive metal electrode is a mesh electrode; the conductive metal electrode is selected from at least one of copper electrode, nickel cloth and silver cloth.
According to some embodiments of the invention, the sensitivity of the pressure sensor may be 10000-40000kPa -1 。
A second aspect of the present invention provides a method of manufacturing a pressure sensor having a unidirectional electrical conductivity function, the method comprising the steps of:
the magnetic conductive fibers are directionally distributed in the matrix material, and the flexible electrode is assembled;
wherein the magnetic conductive fibers are aligned perpendicular to the flexible electrode orientation.
According to some embodiments of the invention, the manner of assembling the flexible electrode comprises: curing the flexible electrode and the matrix material distributed with the magnetic conductive fibers together;
or after the matrix material with the magnetic conductive fibers distributed is solidified, the flexible electrode is adhered.
Wherein curing the flexible electrodes together with the matrix material with the magnetically conductive fibers distributed may mean that one or more of the flexible electrodes are cured together with the matrix material with the magnetically conductive fibers distributed.
According to some embodiments of the invention, the magnetic conductive fibers are directionally distributed in the matrix material in the following manner:
the magnetic conductive fibers and the matrix material are mixed and placed in a mold, and the conductive fibers are directionally distributed in the matrix material in a direction parallel to a magnetic field under the induction of the magnetic field perpendicular to the mold.
In the invention, the mode of covering the upper surface flexible electrode first and then solidifying is adopted, so that the contact resistance can be reduced, the device is stabilized, and meanwhile, the preparation flow is simplified.
According to some embodiments of the invention, the weight ratio of the base material to the magnetically conductive fibers is (5-20): 1.
the magnetically conductive fibers, the base material and the flexible electrode according to the second aspect of the present invention have the same meaning as the aforementioned first aspect. And will not be described in detail herein.
According to some embodiments of the invention, the mold may be a flat plate mold. In order to obtain better effect, the bottom of the die is made of sand paper. Wherein, the sand paper surface is the sphenoid ridge structure, can effectively improve the sensing sensitivity.
According to some embodiments of the invention, the mixing is performed under stirring. The stirring speed can be 1500-3000rpm, and the stirring time can be 20-30min;
according to some embodiments of the invention, the magnetic field induced conditions may include: the magnetic field strength is 0.1-0.3T; the magnetic field induction is performed under a uniform magnetic field.
According to some embodiments of the invention, the curing is photo-curing or thermal-curing.
Preferably, the conditions of the photo-curing include: the ultraviolet light has the wavelength of 360-380nm, the intensity of 20-50W and the time of 20-30s.
Preferably, the conditions for thermal curing include: 70-80 ℃ for 60-90min.
In the present invention, the manner of assembling the flexible electrode is not particularly limited as long as the requirements of the present invention can be satisfied. For example, the assembly may be by lamination and/or by gluing.
The third aspect of the invention provides a pressure sensor prepared by the method.
A fourth aspect of the invention provides the use of the aforementioned pressure sensor in the field of wearable devices and/or human-computer interactions.
The method of the invention can also be applied to 3D printing, and can be used for orientation printing of sample materials with specific patterns.
A fifth aspect of the invention provides a wearable device comprising the aforementioned pressure sensor.
The present invention will be described in detail by examples.
Example 1
(1) Adding 4g of nickel-plated carbon fiber (with the diameter of 0.2mm, the length of 2mm, the conductivity of 1.5X10-3 omega cm and the magnetic conductivity of 8X 103H/m) into 16g of matrix material (polydimethylsiloxane (PDMS)), stirring for 20min at 2000rpm, pouring the mixture into a flat mold (material: acrylic (polymethyl methacrylate; 4cm (length) ×4cm (width) ×2mm (height)) with rough-surfaced sand paper at the bottom of the mold), scraping the surfaces of the nickel-plated carbon fiber and the matrix material (uniformly scraping a film on the matrix material by a thin blade) after mixing, flattening the surfaces of the nickel-plated carbon fiber and the matrix material, placing the mold filled with the nickel-plated carbon fiber and the matrix material in a magnetic field in the vertical direction, and directionally twisting the nickel-plated carbon fiber therein along the magnetic field direction under the induction of a magnetic field (uniform magnetic field) of 0.2T to obtain a dielectric layer precursor; then covering a layer of conductive film (copper net, 4cm (length) x 4cm (width)) with the thickness of 50 μm on the upper surface of the obtained dielectric layer precursor, standing at room temperature for 10min, and self-leveling to obtain the dielectric layer precursor with the upper surface covered with the conductive film;
performing heat curing on the obtained dielectric layer precursor at 70 ℃ for 60min to obtain a dielectric layer with the upper surface covered with a conductive film, wherein the thickness of the dielectric layer is 2mm;
(2) Preparing an interdigital electrode by magnetron sputtering (the time is 30 min), wherein the thickness of copper deposited on the interdigital electrode is 100nm, the thickness of the interdigital electrode is 72 mu m, and the interdigital line width and the line distance of the interdigital electrode are 150 mu m respectively; and adhering the electrode to the lower surface of the dielectric layer with the upper surface covered by the conductive film as a lower electrode.
Example 2
(1) Adding 4.4g of nickel-plated carbon fiber (with the diameter of 0.2mm, the length of 2mm, the conductivity of 1.5X10-3 omega cm and the magnetic conductivity of 8X 103H/m) into 15.6g of matrix material (polydimethylsiloxane (PDMS)), stirring for 20min at 2000rpm, pouring the mixture into a flat mold (material: acrylic (polymethyl methacrylate; 4cm (length) ×4cm (width) ×2mm (height)) with rough surface at the bottom of the mold), scraping the surfaces of the mixed nickel-plated carbon fiber and matrix material (uniformly scraping a film on the matrix material by a thin blade), flattening the surfaces of the mixed nickel-plated carbon fiber and matrix material, placing the mold filled with the nickel-plated carbon fiber and matrix material in a magnetic field in the vertical direction, and directionally twisting the nickel-plated carbon fiber therein along the magnetic field direction under the induction of a magnetic field of 0.2T (uniform magnetic field), thereby obtaining a dielectric layer precursor; then covering the upper surface of the obtained dielectric layer with a conductive film (copper net, 4cm (length) x 4cm (width)) with the thickness of 50 μm, standing at room temperature for 10min, and self-leveling to obtain a dielectric layer precursor with the upper surface covered with the conductive film;
performing heat curing on the obtained dielectric layer precursor at 70 ℃ for 60min to obtain a dielectric layer with the upper surface covered with a conductive film, wherein the thickness of the dielectric layer is 2mm;
(2) Preparing an interdigital electrode by magnetron sputtering (the time is 30 min), wherein the thickness of copper deposited on the interdigital electrode is 100nm, the thickness of the interdigital electrode is 72 mu m, and the interdigital line width and the line distance of the interdigital electrode are 150 mu m respectively; and adhering the electrode to the lower surface of the dielectric layer with the upper surface covered by the conductive film as a lower electrode.
Example 3
(1) Adding 3.6g of nickel-plated carbon fiber (with the diameter of 0.2mm, the length of 2mm, the conductivity of 1.5X10-3 omega cm and the magnetic conductivity of 8X 103H/m) into 16.4g of matrix material (polydimethylsiloxane (PDMS)), stirring for 20min at 2000rpm, pouring the mixture into a flat mold (material: acrylic (polymethyl methacrylate; 4cm (length) ×4cm (width) ×2mm (height)) with rough surface at the bottom of the mold), scraping the surfaces of the mixed nickel-plated carbon fiber and matrix material (uniformly scraping a film on the matrix material by a thin blade), flattening the surfaces of the mixed nickel-plated carbon fiber and matrix material, placing the mold filled with the nickel-plated carbon fiber and matrix material in a magnetic field in the vertical direction, and directionally twisting the nickel-plated carbon fiber therein along the magnetic field direction under the induction of a magnetic field of 0.2T (uniform magnetic field), thereby obtaining a dielectric layer precursor; then covering the upper surface of the obtained dielectric layer with a conductive film (copper net, 4cm (length) x 4cm (width)) with the thickness of 50 μm, standing at room temperature for 10min, and self-leveling to obtain a dielectric layer precursor with the upper surface covered with the conductive film;
performing heat curing on the obtained dielectric layer precursor at 70 ℃ for 60min to obtain a dielectric layer with the upper surface covered with a conductive film, wherein the thickness of the dielectric layer is 2mm;
(2) Preparing an interdigital electrode by magnetron sputtering (the time is 30 min), wherein the thickness of copper deposited on the interdigital electrode is 100nm, the thickness of the interdigital electrode is 72 mu m, and the interdigital line width and the line distance of the interdigital electrode are 150 mu m respectively; and adhering the electrode to the lower surface of the dielectric layer with the upper surface covered by the conductive film as a lower electrode.
Example 4
(1) Adding 4g of nickel-plated carbon fiber (with the diameter of 0.2mm, the length of 2mm, the conductivity of 1.5X10-3 omega cm and the magnetic conductivity of 8X 103H/m) into 16g of matrix material (polydimethylsiloxane (PDMS)), stirring for 20min at 2000rpm, pouring the mixture into a flat mold (material: acrylic (polymethyl methacrylate; 4cm (length) ×4cm (width) ×2mm (height)), wherein the bottom of the mold is made of smooth acrylic material), scraping the surfaces of the nickel-plated carbon fiber and the matrix material after mixing (uniformly scraping a film on the matrix material by a thin blade), flattening the surfaces of the nickel-plated carbon fiber and the matrix material, placing the mold filled with the nickel-plated carbon fiber and the matrix material in a magnetic field in the vertical direction, and directionally twisting the nickel-plated carbon fiber therein along the magnetic field direction under the induction of a magnetic field of 0.2T (uniform magnetic field), thereby obtaining a dielectric layer precursor; then covering the upper surface of the obtained dielectric layer with a conductive film (copper net, 4cm (length) x 4cm (width)) with the thickness of 50 μm, standing at room temperature for 10min, and self-leveling to obtain a dielectric layer precursor with the upper surface covered with the conductive film;
performing heat curing on the obtained dielectric layer precursor at 70 ℃ for 60min to obtain a dielectric layer with the upper surface covered with a conductive film, wherein the thickness of the dielectric layer is 2mm;
(2) Preparing an interdigital electrode by magnetron sputtering (the time is 30 min), wherein the thickness of copper deposited on the interdigital electrode is 100nm, the thickness of the interdigital electrode is 72 mu m, and the interdigital line width and the line distance of the interdigital electrode are 150 mu m respectively; and adhering the electrode to the lower surface of the dielectric layer with the upper surface covered by the conductive film as a lower electrode.
Comparative example 1
The procedure of example 1 was followed, except that the orientation induction of the nickel-plated carbon fiber was not performed with a magnetic field.
And (3) performing effect test on the obtained pressure sensor:
in fig. 3, (a) is a pressure sensor prepared in example 1, example 4, and comparative example 1, to which a variable pressure was applied using a linear motor, wherein a digital source meter of time-2400 (to apply a constant voltage, and a digital source meter of time-6517 was used to conduct a current test.
The test results in fig. 3 (a) show that the pressure sensors prepared in example 1, example 4 and comparative example 1 have better responsiveness to pressure.
The different curves, different slopes for (a) in fig. 3, respectively, illustrate that the pressure sensor prepared in example 1 has a significantly higher responsiveness to pressure than in example 4 and comparative example 1.
The test conditions in fig. 3 (b) are the same as those in fig. 3 (a), and represent the response currents of example 1, example 2 and example 3 to different pressures, respectively.
The different curves, different slopes for (a) in fig. 3 illustrate that the pressure sensor prepared in example 1 has a significantly higher responsiveness to pressure than in examples 2 and 3, respectively.
Fig. 3 (c) is a graph showing the voltage versus current for the pressure sensor prepared in example 1. The test method is that an electrochemical workstation applies variable voltage and tests the current. The results show that the pressure sensor prepared in example 1 is a pure resistive device.
The test methods (d) - (g) in fig. 3 are the same as (a) and (b).
FIG. 3 (d) shows the corresponding currents for the pressure sensors prepared in example 1 at specific applied pressures (1-100 kPa, such as 1kPa, 15kPa, 38kPa, 48kPa, and 58 kPa); the results indicate that the output current signal is stable under the same pressure stimulus and increases with increasing pressure.
In fig. 3 (e), the output current of the pressure sensor prepared in example 1 increases with increasing frequency, and does not increase with increasing frequency of applied force.
In fig. 3, (f) shows that the force is applied to the pressure sensor prepared in example 1, the response time of the current is 30ms, and the force is applied to generate a current signal immediately. Indicating that the device signal responds quickly to pressure.
Fig. 3 (g) shows that the current signal of the pressure sensor prepared in example 1 still maintains good stability under 3000 cycles.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (24)
1. A pressure sensor having unidirectional electrical conductivity, the pressure sensor comprising: two layers of flexible electrodes and a dielectric layer positioned between the two layers of flexible electrodes; the dielectric layer comprises a matrix material and magnetic conductive fibers distributed in the matrix material, and the magnetic conductive fibers are arranged in an orientation perpendicular to the flexible electrode;
wherein the magnetic conductive fiber is at least one selected from nickel-plated carbon fiber, nickel-plated metal fiber, nickel-plated stainless steel, iron-plated carbon fiber and cobalt-plated carbon fiber; the matrix material is selected from a thermally curable material and/or a photo-curable material.
2. The pressure sensor of claim 1, wherein the weight ratio of the matrix material to the magnetically conductive fibers is (3-25): 1, a step of;
and/or, the magnetic conductive fiber is cylindrical;
and/or the conductivity of the magnetic conductive fiber is (1.5-2) multiplied by 10 -3 Omega cm; permeability of (8-9). Times.10 3 H/m。
3. The pressure sensor of claim 2, wherein the magnetically conductive fibers have a length of 0.5-3mm and a diameter of 0.1-0.3mm.
4. A pressure sensor according to claim 3, wherein the magnetically conductive fibres are nickel plated carbon fibres and/or cobalt plated carbon fibres.
5. The pressure sensor of any one of claims 1-4, wherein the dielectric layer has a thickness of 2mm-5mm.
6. The pressure sensor of claim 5, wherein the thermally curable material is selected from polydimethylsiloxane and/or silica gel; the light-cured material is photosensitive polyurethane.
7. The pressure sensor of any one of claims 1-4, 6, wherein the thickness of the two layers of flexible electrodes are each independently 20 μιη -70 μιη;
and/or the flexible electrode is selected from an interdigital electrode and/or a conductive metal electrode;
the upper electrode of the pressure sensor is a conductive metal electrode, and the lower electrode is an interdigital electrode;
the number of pairs of the interdigital electrodes is 8-20;
the interdigital line width and the line distance of the interdigital electrode are respectively and independently 100-200 mu m.
8. The pressure sensor of claim 7, wherein the conductive metal electrode is a mesh electrode; the conductive metal electrode is selected from at least one of copper electrode, nickel cloth and silver cloth.
9. The pressure sensor of claim 5, wherein the thickness of the two layers of flexible electrodes are each independently 20-70 μιη;
and/or the flexible electrode is selected from an interdigital electrode and/or a conductive metal electrode;
the upper electrode of the pressure sensor is a conductive metal electrode, and the lower electrode is an interdigital electrode;
the number of pairs of the interdigital electrodes is 8-20;
the interdigital line width and the line distance of the interdigital electrode are respectively and independently 100-200 mu m.
10. The pressure sensor of claim 9, wherein the conductive metal electrode is a mesh electrode; the conductive metal electrode is selected from at least one of copper electrode, nickel cloth and silver cloth.
11. The pressure sensor of any one of claims 1-4, 6, 8-10, wherein the pressure sensor has a sensitivity of 10000-40000kPa -1 。
12. The pressure sensor of claim 5, wherein the sensitivity of the pressure sensor is 10000-40000kPa -1 。
13. The pressure sensor of claim 7, wherein the sensitivity of the pressure sensor is 10000-40000kPa -1 。
14. A method of making a pressure sensor having unidirectional electrical conductivity, the method comprising: the magnetic conductive fibers are directionally distributed in the matrix material, and the flexible electrode is assembled;
the magnetic conductive fibers are arranged in an orientation perpendicular to the flexible electrode;
the manner of assembling the flexible electrode includes: curing the flexible electrode and the matrix material distributed with the magnetic conductive fibers together; or, after the matrix material distributed with the magnetic conductive fibers is solidified, adhering the flexible electrode; wherein the curing is photo-curing or thermal-curing;
the mode that the magnetic conductive fibers are directionally distributed on the matrix material is as follows:
mixing the magnetic conductive fibers and the matrix material, and placing the mixture in a mold, wherein the conductive fibers are directionally distributed in the matrix material in a direction parallel to a magnetic field under the induction of the magnetic field perpendicular to the mold;
the weight ratio of the matrix material to the magnetic conductive fiber is (5-20): 1, a step of;
the magnetic conductive fiber is cylindrical; the length of the magnetic conductive fiber is 0.5-3mm, and the diameter is 0.1-0.3mm;
the conductivity of the magnetic conductive fiber is (1.5-2) multiplied by 10 -3 Omega cm; permeability of (8-9). Times.10 3 H/m；
The magnetic conductive fiber is at least one selected from nickel plating carbon fiber, nickel plating metal fiber, nickel plating stainless steel, iron plating carbon fiber and cobalt plating carbon fiber;
the matrix material is selected from a thermally curable material and/or a photo-curable material.
15. The method of claim 14, wherein the mold is a flat plate mold; the bottom of the die is made of sand paper;
and/or, the mixing is performed under agitation; the stirring speed is 1500-3000rpm, and the stirring time is 20-30min;
and/or, the magnetic field inducing conditions include: the magnetic field strength is 0.1-0.3T; the magnetic field induction is performed under a uniform magnetic field.
16. The method of claim 15, wherein the magnetically conductive fibers are nickel plated carbon fibers and/or cobalt plated carbon fibers.
17. The method of claim 15, wherein the thermally curable material is selected from polydimethylsiloxane and/or silica gel; the light-cured material is photosensitive polyurethane.
18. The method of claim 15, wherein the light curing conditions comprise: the wavelength of ultraviolet light is 360-380nm, the intensity is 20-50W, and the time is 20-30s; the conditions for thermal curing include: 70-80 ℃ for 60-90min.
19. The method of any one of claims 14-18, wherein the flexible electrode has a thickness of 20 μιη -70 μιη;
and/or the flexible electrode is selected from an interdigital electrode and/or a conductive metal electrode;
the upper electrode of the pressure sensor is a conductive metal electrode, and the lower electrode is an interdigital electrode;
the number of pairs of the interdigital electrodes is 8-20;
the interdigital line width and the line distance of the interdigital electrode are respectively and independently 100-200 mu m;
the interdigital electrode is prepared by magnetron sputtering, wherein the time of the magnetron sputtering is 20-40min,
and/or the magnetron sputtering is carried out so that the thickness of the deposited metal on the interdigital electrode is 70-100nm, and the deposited metal is selected from copper and/or gold.
20. The method of claim 19, wherein the conductive metal electrode is a mesh electrode; the conductive metal electrode is selected from at least one of copper electrode, nickel cloth and silver cloth.
21. The method of claim 19, wherein the deposited metal is selected from copper.
22. A pressure sensor prepared by the method of any one of claims 14-21.
23. Use of the pressure sensor of any one of claims 1-13 and 22 in the field of wearable devices and/or human-computer interactions.
24. A wearable device, characterized in that it comprises the pressure sensor of any one of claims 1-13 and 22.
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