Flexible electrode, preparation method thereof and flexible electrode material containing flexible electrode

Abstract

The invention discloses a flexible electrode, a preparation method thereof and a flexible electrode material comprising the flexible electrode, the flexible electrode comprises an electrode layer, the electrode layer is embedded on an elastomer, the electrode layer is in a vertically and horizontally interlaced line grid on a vertical projection, and the electrode layer is in a concave-convex wavy line on the vertical projection; the coating is prepared through the processes of spin coating, embossing and spraying. The flexible electrode disclosed by the invention is simple in structure, simple and easy in preparation operation steps, good in compatibility and fitness and stable in conductivity.

Description

Technical Field

[0001] The invention relates to a flexible electrode, a preparation method thereof and a flexible electrode material containing the same, and belongs to the technical field of flexible electrodes. Background Art

[0002] Flexible electrodes are electronic components based on flexible or ductile materials. The electrode materials have good conductivity and flexibility, and are widely used in wearable electronic devices. As the interface between wearable electronic devices and the human body, flexible electrodes can adapt to the softness, elasticity and bending characteristics of human tissues, and have great future applications in health-related fields.

[0003] Traditional flexible electrodes rely on standard microelectronics manufacturing processes, including vacuum deposition of thin films, spin coating, photolithography, and dry / wet etching. These traditional flexible electrodes have certain shortcomings: the preparation process is complex and the compatibility is poor, which is not conducive to the commercial use of flexible electrodes; most electrodes have poor adhesion to human skin, which easily causes signal artifacts. Summary of the invention

[0004] In order to solve at least one problem existing in the above-mentioned prior art, the present invention provides a flexible electrode, a preparation method thereof and a flexible electrode material containing the same. The flexible electrode has a simple structure, simple and easy preparation steps, good compatibility and conformability, and stable conductive performance.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a flexible electrode, comprising an electrode layer, wherein the electrode layer is embedded in an elastomer, wherein the elastomer comprises a flexible conductive layer and a flexible insulating layer, wherein the electrode layer is arranged between the flexible conductive layer and the flexible insulating layer, and wherein the electrode layer presents a grid of lines interwoven vertically and horizontally in a vertical projection, and presents a wavy line with undulating shapes in a vertical projection.

[0006] Preferably, the flexible conductive layer contains conductive carbon black.

[0007] Preferably, a connection area is provided on a side of the flexible insulating layer close to the flexible conductive layer, a wire connection portion is provided in the connection area, and the wire connection portion is electrically connected to the electrode layer.

[0008] Preferably, the electrode layer is one of an aluminum-silver-plated electrode layer, a copper-silver-plated electrode layer, a pure silver electrode layer, and a nickel-coated graphite electrode layer.

[0009] Preferably, the electrode layer has a thickness of 10-30 μm and a line width of 1-2.5 mm.

[0010] Preferably, the elastic body is also provided with ventilation holes.

[0011] The present invention also provides a method for preparing a flexible electrode, the steps of which are as follows: (1) Spin coating on a rigid base layer to form a flexible conductive layer, followed by semi-curing; (2) embossing the surface of the semi-cured flexible conductive layer away from the base layer, wherein the pattern is a grid of lines interlaced vertically and horizontally on the surface in vertical projection and wavy lines with undulating shapes on the surface in vertical projection; (3) growing an electrode layer using the embossed pattern as a base layer; (4) spin coating a flexible insulating layer using the unembossed portion of the flexible conductive layer and the electrode layer as a base layer, and then curing the flexible insulating layer and the flexible conductive layer to form an elastomer; (5) Punching holes in the portion of the elastomer that is not covered by the electrode layer to form air-permeable through holes, the air-permeable through holes penetrate the flexible conductive layer and the flexible insulating layer, and the elastomer is peeled off from the rigid base layer to obtain a flexible electrode.

[0012] Preferably, in step (3), after the electrode layer is generated, a wire connection portion is placed at a position of the electrode layer, and the wire connection portion is covered by a flexible insulating layer.

[0013] Preferably, in step (3), the electrode layer is grown by sputtering.

[0014] The present invention also provides a flexible electrode material, which is an elastomer for making a flexible electrode, wherein the elastomer comprises a flexible conductive layer and a flexible insulating layer; the flexible conductive layer comprises polydimethylsiloxane, polydopamine, carboxylated cellulose nanofibers and conductive carbon black; the flexible insulating layer comprises polydimethylsiloxane, carboxylated cellulose nanofibers and polyurethane resin.

[0015] Preferably, the flexible conductive layer comprises, by weight, 60-67 parts of polydimethylsiloxane, 27-32 parts of carboxylated cellulose nanofibers, 8-12 parts of polydopamine and 6-9 parts of conductive carbon black.

[0016] Preferably, the flexible insulating layer comprises, by weight, 60-67 parts of polydimethylsiloxane, 32-37 parts of carboxylated cellulose nanofibers and 10-15 parts of polyurethane resin.

[0017] Preferably, the diameter of the carboxylated cellulose nanofibers is 4-10 nm and the length is 100-200 nm.

[0018] Preferably, the particle size of polydopamine is 100-150 nm.

[0019] Preferably, the particle size of the conductive carbon is less than 30 nm.

[0020] Preferably, the particle size of the polyurethane resin powder is 100-150 nm.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the flexible electrode of the present invention has a simple structure, the preparation operation steps are simple and easy, it has good compatibility, and stable conductive performance; the flexible electrode prepared by the present invention has good flexibility, which can make it have good ductility and can adapt to the characteristics of complex skin surfaces; the flexible conductive layer of the flexible electrode prepared by the present invention has good adhesion performance and can have good fit with human skin; the elastomer prepared by the present invention makes the resistance signal of the flexible electrode have no obvious change under large tensile strain, thereby improving the resistance stability of the flexible electrode of the present invention, and also improving the stability of the conductive ability under tensile strain. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A top view of a flexible electrode of the present invention; Figure 2 A vertical cross-sectional view of a flexible electrode of the present invention; Figure 3 This is a cycle life diagram of the flexible electrode of the present invention.

[0023] Figure: 0, rigid base layer, 1, flexible conductive layer, 2, electrode layer, 3, flexible insulating layer, 4, breathable through hole, 5, wire connection part. DETAILED DESCRIPTION

[0024] The technical scheme in the implementation of the present invention is clearly and completely described below in conjunction with the accompanying drawings. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the conditions recommended by the normal conditions or the manufacturers. If the manufacturers are not specified in the reagents, instruments, and components used, they are all conventional products that can be purchased commercially.

[0025] An embodiment of the present invention provides a flexible electrode, including an electrode layer 2, wherein the electrode layer 1 is embedded in an elastomer, the elastomer includes a flexible conductive layer 1 and a flexible insulating layer 3, the electrode layer 2 is arranged between the flexible conductive layer 1 and the flexible insulating layer 3, and the electrode layer presents a grid of lines interwoven vertically and horizontally in a vertical projection, and presents a wavy line with undulating shapes in a vertical projection.

[0026] The flexible conductive layer 1 in the embodiment contains conductive carbon black.

[0027] In the embodiment, a connection area is provided on one side of the flexible insulating layer 3 close to the flexible conductive layer. A wire connection portion 5 is provided in the connection area. The wire connection portion is electrically connected to the electrode layer.

[0028] The electrode layer 3 in the embodiment is one of an aluminum-silver-plated electrode layer, a copper-silver-plated electrode layer, a pure silver electrode layer, and a nickel-coated graphite electrode layer.

[0029] The electrode layer in the embodiment has a thickness of 10 to 30 μm and a line width of 1 to 2.5 mm.

[0030] The elastic body in the embodiment is further provided with air-permeable through holes 4, and the air-permeable through holes 4 are distributed around the electrode layer.

[0031] An embodiment of the present invention further provides a method for preparing a flexible electrode, the steps of which are as follows: (1) Spin coating to form a flexible conductive layer 1 on a rigid base layer 0, and then semi-curing; (2) embossing the surface of the semi-cured flexible conductive layer 1 away from the base layer, wherein the pattern is a grid of lines interlaced vertically and horizontally on the surface in vertical projection, and wavy lines with undulating shapes on the surface in vertical projection; (3) growing an electrode layer 2 using the embossed pattern as a base layer; (4) spin coating a flexible insulating layer 3 using the unembossed portion of the flexible conductive layer 1 and the electrode layer 2 as a base layer, and then curing the flexible insulating layer 3 and the flexible conductive layer 1 to form an elastic body; (5) Punching holes in the portion of the elastomer not covering the electrode layer to form air-permeable through holes 4, which penetrate the flexible conductive layer 1 and the flexible insulating layer 3, and peeling the elastomer off the rigid base layer 0 to obtain a flexible electrode.

[0032] After the electrode layer 3 in the embodiment is generated, a wire connection portion 5 may be placed at a position of the electrode layer 3 , and the wire connection portion 5 is covered by the flexible insulating layer 3 .

[0033] The electrode layer 3 in the embodiment is grown by sputtering.

[0034] The elastomer in the implementation manner is used as a flexible electrode material to make a flexible electrode, and the elastomer includes a flexible conductive layer and a flexible insulating layer.

[0035] The flexible conductive layer in the embodiment includes, by weight, 60 to 67 parts of polydimethylsiloxane, 27 to 32 parts of carboxylated cellulose nanofibers, 8 to 12 parts of polydopamine, and 6 to 9 parts of conductive carbon black.

[0036] The particle size of the polydopamine in the embodiment is 100-150 nm; the particle size of the conductive carbon is selected to be less than 30 nm; the diameter of the carboxylated cellulose nanofiber is 4-10 nm, and the length is 100-200 nm.

[0037] The flexible insulating layer in the embodiment includes, by weight, 60 to 67 parts of polydimethylsiloxane, 32 to 37 parts of carboxylated cellulose nanofibers, and 10 to 15 parts of polyurethane resin powder.

[0038] The particle size of the polyurethane resin powder in the embodiment is 100-150 nm; the diameter of the carboxylated cellulose nanofiber is 4-10 nm, and the length is 100-200 nm.

[0039] Example 1 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 8 parts of polydopamine with a size of 100-150 nm, and 6 parts of conductive carbon black with a size of 30 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 10 parts of polyurethane resin powder with a size of 100-150 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; S3, spin coating the flexible conductive layer slurry on the rigid base layer 0 to a preset thickness to form a flexible conductive layer 1, and semi-curing at 40-45° C.; S4, embossing the surface of the semi-cured flexible conductive layer 1 away from the base layer, wherein the pattern is a grid of lines interlaced vertically and horizontally on the vertical projection surface and wavy lines with undulating shapes on the vertical projection surface, with a line width of 1.5 mm and a thickness of 8 μm; S5, using the embossed pattern as the base layer to spray pure silver particles by sputtering, the particle size is less than 50 μm, and an electrode layer 2 is grown, and the thickness of the electrode layer is 15 μm; S6, using the unembossed part of the flexible conductive layer 1 and the electrode layer 2 as the base layer, spin-coating the flexible insulating layer slurry to a preset thickness to form a flexible insulating layer 3, and then curing at 65-70°C, so that the flexible insulating layer 3 with a thickness of 0.5 mm and the flexible conductive layer 1 with a thickness of 0.5 mm form an elastomer; S7, punching holes in the portion of the elastomer not covering the electrode layer to form air-permeable through holes 4, the air-permeable through holes penetrate the flexible conductive layer 1 and the flexible insulating layer 3, peeling the elastomer off the rigid base layer to obtain a flexible electrode.

[0040] Example 2 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: The difference between the present embodiment 2 and the embodiment 1 is that: S5, using the embossed pattern as the base layer, aluminum-silver-plated particles are sprayed by sputtering coating, the particle size is less than 50 μm, and the electrode layer 2 is grown, and the thickness of the electrode layer is 15 μm; and a wire connection part 5 is placed at a position of the electrode layer 3; S6, using the unembossed portion of the flexible conductive layer 1, the electrode layer 2, and the wire connection portion 5 as the base layer, spin-coating the flexible insulating layer slurry to a preset thickness to form a flexible insulating layer 3, and then curing at 65-70° C., so that the flexible insulating layer 3 and the flexible conductive layer 1 form an elastic body; The remaining steps are the same as those in Example 1.

[0041] Example 3 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 30 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 10 parts of polydopamine with a size of 100-150 nm, and 7 parts of conductive carbon black with a size of 30 nm are added to 63 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 35 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, and 12.5 parts of polyurethane resin powder with a size of 100-150 nm are added to 63 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The remaining steps are the same as those in Example 1.

[0042] Example 4 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 12 parts of polydopamine with a size of 100-150 nm, and 9 parts of conductive carbon black with a size of 30 nm are added to 67 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 37 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 15 parts of polyurethane resin powder with a size of 100-150 nm are added to 67 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The remaining steps are the same as those in Example 1.

[0043] Example 5 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 28 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 11 parts of polydopamine with a size of 100-150 nm, and 8 parts of conductive carbon black with a size of 30 nm are added to 65 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 10 parts of polyurethane resin powder with a size of 100-150 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The remaining steps are the same as those in Example 1.

[0044] Example 6 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 8 parts of polydopamine with a size of 100-150 nm, and 6 parts of conductive carbon black with a size of 30 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 33 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 14 parts of polyurethane resin powder with a size of 100-150 nm are added to 64 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The remaining steps are the same as those in Example 1.

[0045] Example 7 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 31 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 11 parts of polydopamine with a size of 100-150 nm, and 6 parts of conductive carbon black with a size of 30 nm are added to 62 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 36 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 13 parts of polyurethane resin powder with a diameter of 100-150 nm are added to 61 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The remaining steps are the same as those in Example 1.

[0046] Comparative Example 1 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1. Add 8 parts of 100-150nm polydopamine and 6 parts of 30nm conductive carbon black into 60 parts of polydimethylsiloxane, disperse them evenly by planetary dispersion, add curing agent and stir evenly to obtain flexible conductive layer slurry for later use; S2. Add 10 parts of 100-150 nm polyurethane resin powder to 60 parts of polydimethylsiloxane, disperse evenly by planetary dispersion, add curing agent and stir evenly to obtain flexible insulation layer slurry for standby use; The difference between this comparative example 1 and the example 1 is that the flexible conductive layer material and the flexible insulating layer material of the elastomer do not contain carboxylated cellulose nanofibers; The remaining steps are the same as those in Example 1.

[0047] Comparative Example 2 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 50-100 nm and a length of 1-3 μm, 8 parts of polydopamine with a size of 100-150 nm, and 6 parts of conductive carbon black with a size of 30 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 32 parts of carboxylated cellulose nanofibers with a diameter of 50-100 nm and a length of 1-3 μm, and 10 parts of 100-150 nm polyurethane resin powder are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulation layer slurry for standby use; The difference between this comparative example 2 and the example 1 is that the particle size of the carboxylated cellulose nanofibers in the flexible conductive layer material and the flexible insulating layer material of the elastomer is 50-100 nm in diameter and 1-3 μm in length; The remaining steps are the same as those in Example 1.

[0048] Comparative Example 3 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, and 14 parts of 30 nm conductive carbon black are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 10 parts of polyurethane resin powder with a size of 100-150 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; This comparative example 3 is different from example 1 in that: the flexible conductive layer material of the elastomer does not contain polydopamine; The remaining steps are the same as those in Example 1.

[0049] Comparative Example 4 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 8 parts of polydopamine with a size of 300-400 nm, and 6 parts of conductive carbon black with a size of 30 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 10 parts of polyurethane resin powder with a size of 100-150 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The difference between this comparative example 4 and example 1 is that the particle size of the polydopamine of the flexible conductive layer material of the elastomer is 300-400 nm; The remaining steps are the same as those in Example 1.

[0050] Comparative Example 5 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 8 parts of polydopamine with a size of 100-150 nm, and 6 parts of conductive carbon black with a size of 50-100 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm and 10 parts of polyurethane resin powder with a size of 100-150 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible insulating layer slurry for standby use; The difference between this comparative example 5 and the example 1 is that the conductive carbon black particle size of the flexible conductive layer material of the elastomer is 50-100 nm; there is agglomeration in the flexible conductive layer slurry; The remaining steps are the same as those in Example 1.

[0051] Comparative Example 6 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: S1, 27 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm, 8 parts of polydopamine with a size of 100-150 nm, and 6 parts of conductive carbon black with a size of 30 nm are added to 60 parts of polydimethylsiloxane, dispersed evenly by planetary dispersion, and then a curing agent is added and stirred evenly to obtain a flexible conductive layer slurry for standby use; S2, add 32 parts of carboxylated cellulose nanofibers with a diameter of 4-10 nm and a length of 100-200 nm into 60 parts of polydimethylsiloxane, disperse them evenly by planetary dispersion, add a curing agent and stir evenly to obtain a flexible insulating layer slurry for standby use; This comparative example 6 is different from the example 1 in that: the flexible insulating layer material of the elastomer does not contain polyurethane resin powder; The remaining steps are the same as those in Example 1.

[0052] Comparative Example 7 A method for preparing a flexible electrode material and a flexible electrode, the specific steps are as follows: The difference between this comparative example 7 and the example 1 is that: S4, embossing is performed on the surface of the semi-cured flexible conductive layer 1 away from the base layer, the pattern is a grid of lines interlaced vertically and horizontally on the vertical projection surface, and horizontal straight lines on the vertical projection surface, the line width is 1.5 mm, and the thickness is 8 μm; The remaining steps are the same as those in Example 1.

[0053] Related effect test: 1. Conductive properties: The flexible conductive layer slurry of the flexible electrodes of Example 1, Examples 3 to 7 and Comparative Examples 1 to 7 was spin-coated on a rigid base layer 0 to a preset thickness and cured to form a flexible conductive layer with a thickness of 0.5 mm. The samples were cut into 10 mm × 20 mm samples, and their ohmic resistance was measured and the conductivity was calculated. The conductivity (S / m) results are shown in Table 1.

[0054] 2. Conductive properties: The flexible electrodes of Example 1, Examples 3 to 7 and Comparative Examples 1 to 7 were taken as samples respectively, both ends of the samples were fixed with clamps, tensile stress was applied to the samples, and the strain under tensile stress was measured to calculate the Young's modulus. The results of Young's modulus (Mpa) are shown in Table 1.

[0055] 3. Adhesion performance: The flexible electrodes of Example 1, Examples 3 to 7 and Comparative Examples 1 to 7 were taken as samples, and the flexible conductive layers of the samples were subjected to adhesion tests with the PET and pig skin substrates, respectively, to obtain the interfacial energy (also binding energy) of the flexible electrode and the two substrates, the interfacial energy (J / m 2)The results are shown in Table 1.

[0056] 4. Corresponding characteristics of tensile strain: The flexible electrodes of Example 1, Examples 3 to 7 and Comparative Examples 1 to 7 were taken as samples respectively; the resistance signals of the samples at 15%, 30% and 50% tensile strain were measured, and the resistance change rate was (resistance signal after stretching - resistance signal before stretching) / resistance signal before stretching × 100%. The corresponding characteristic results of tensile strain are shown in Table 1.

[0057] 5. Resistance stability: The flexible electrodes of Example 1, Example 7 and Comparative Examples 1 to 7 were taken as samples, and stretched in cycles, each with a stretching strain of 50%. The change of the resistance signal after stretching was calculated as (resistance signal after stretching stopped - resistance signal before stretching) / resistance signal before stretching × 100% as the resistance change rate. The resistance stability was as follows: Figure 3 shown.

[0058] Table 1

[0059] Combined with Table 1, it is found through Comparative Examples 1 and 2 that the material of the flexible conductive layer of Examples 1 and 3 to 7 contains carboxylated cellulose nanofibers and the smaller the particle size, the better the conductivity of the flexible conductive layer. It is found through Comparative Examples 3 and 4 that the material of the flexible conductive layer of Examples 1 and 3 to 7 contains polydopamine and the smaller the particle size, the stronger the conductivity of the flexible conductive layer. It is found through Comparative Example 5 that the material of the flexible conductive layer of Examples 1 and 3 to 7 contains conductive carbon black with a smaller particle size and better dispersibility, so that the conductivity of the flexible conductive layer is better. Therefore, the conductivity effect of the flexible conductive layer of Examples 1 and 3 to 7 is better.

[0060] Combined with Table 1, it is found through Comparative Examples 1 and 2 that the material of the flexible conductive layer of Examples 1 and 3 to 7 contains carboxylated cellulose nanofibers and its particle size is small, the lower the Young's modulus of the flexible electrode, the better the flexibility of the flexible electrode; it is found through Comparative Examples 3 and 4 that the material of the flexible conductive layer of Examples 1 and 3 to 7 contains polydopamine and its particle size is small, which will reduce the Young's modulus of the flexible electrode and help improve the flexibility of the flexible electrode; compared with Examples 1 and 3 to 7, the particle size of the conductive carbon black in Comparative Example 5 is large, which will increase the Young's modulus of the flexible electrode and reduce The flexibility of the flexible electrode is reduced; compared with Example 1 and Examples 3 to 7, the material of the flexible insulating layer of Comparative Example 6 does not contain polyurethane resin powder, which leads to reduced toughness of the flexible electrode and a higher Young's modulus, thereby affecting the flexibility of the flexible electrode; compared with Comparative Example 7, the electrode layer of Example 1 and Examples 3 to 7 is generated on a wavy structure, that is, the flexible conductive layer and the flexible insulating layer have a wavy structure, which can reduce the Young's modulus of the flexible electrode; therefore, the flexible electrode of Example 1 and Examples 3 to 7 has a low Young's modulus of up to 1.8 MPa and has good flexibility.

[0061] Combined with Table 1, the visible interfacial energy of the flexible conductive layer of the flexible electrode of Example 1 and Examples 3 to 7 all reached 98 J / m 2 And above, therefore, the flexible electrode of the present invention has better adhesion performance with the substrate.

[0062] Combined with Table 1, compared with Comparative Examples 1 to 5, the flexible conductive layers of Examples 1 and 3 to 7 contain carboxylated cellulose nanofibers with a small particle size, polydopamine with a small particle size, and the smaller the particle size of the conductive carbon black, the better the structure of the flexible conductive layer is, and the smaller the resistance signal is in response to the tensile strain; compared with Comparative Example 6, the polyurethane resin powder contained in the flexible insulating layer of Examples 1 and 3 to 7 can improve the toughness of the flexible insulating layer, improve the overall stability of the flexible electrode, and also make the resistance signal respond less to the tensile strain. Compared with Comparative Example 7, the electrode layer of Examples 1 and 3 to 7 is generated on a wavy structure. When the wavy structure is stretched, the wavy structure gradually approaches the straight structure, and the length of the electrode layer changes less, so that the resistance signal responds very little to the tensile strain; therefore, the resistance signal of the flexible electrode of Examples 1 and 3 to 7 responds very little to the tensile strain, and the resistance change rate is less than 11% when the tensile strain is 50%.

[0063] Combination Figure 3The flexible electrode of Example 1 is stretched cyclically for less than 4500 times and the resistance signal fluctuates significantly; the flexible electrodes of Examples 2 and 6 are stretched cyclically for less than 5000 times and the resistance signal fluctuates significantly; the flexible electrode of Example 3 is stretched cyclically for less than 6000 times and the resistance signal fluctuates significantly; the flexible electrodes of Examples 3~4 and 7 are stretched cyclically for more than 6000 times but the resistance signal fluctuates significantly, the resistance stability of the flexible electrode is poor, and the resistance signal of Example 7 responds relatively strongly to the tensile strain; while the flexible electrodes of Examples 1 and 7 can achieve more than 6000 cyclic stretchings and the resistance signal of the electrode does not fluctuate significantly after the stretching; therefore, compared with Examples 1 to 7, the resistance of the flexible electrodes of Examples 1 to 7 is more stable, and the stability of the conductive capacity under tensile strain is higher.

[0064] It will be apparent 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 spirit and essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, 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 be included in the present invention.

[0065] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains 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 may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A flexible electrode, characterized in that: It includes an electrode layer, which is embedded in an elastomer. The elastomer includes a flexible conductive layer and a flexible insulating layer. The electrode layer is arranged between the flexible conductive layer and the flexible insulating layer. In a vertical projection, the electrode layer presents a grid of lines interlaced in vertical and horizontal directions, and in a vertical projection, the electrode layer presents a wavy line with uneven contours.

2. A flexible electrode according to claim 1, characterized in that: The electrode layer has a thickness of 10-30 μm and a line width of 1-2.5 mm.

3. A flexible electrode according to claim 1, characterized in that: The electrode layer is one of an aluminum silver-plated electrode layer, a copper silver-plated electrode layer, a pure silver electrode layer, and a nickel-coated graphite electrode layer.

4. The flexible electrode according to claim 1, characterized in that: A connection area is provided on one side of the flexible insulating layer close to the flexible conductive layer, a wire connection portion is provided in the connection area, and the wire connection portion is electrically connected to the electrode layer; The elastic body is also provided with ventilation holes.

5. A method for preparing a flexible electrode, characterized in that: For preparing the flexible electrode according to any one of claims 1 to 4, the steps are as follows: (1) Spin coating on a rigid base layer to form a flexible conductive layer, followed by semi-curing; (2) embossing the surface of the semi-cured flexible conductive layer away from the base layer, wherein the pattern is a grid of lines interlaced vertically and horizontally on the surface in vertical projection and wavy lines with undulating shapes on the surface in vertical projection; (3) growing an electrode layer using the embossed pattern as a base layer; (4) spin coating a flexible insulating layer using the unembossed portion of the flexible conductive layer and the electrode layer as a base layer, and then curing the flexible insulating layer and the flexible conductive layer to form an elastomer; (5) Punching holes in the portion of the elastomer that is not covered by the electrode layer to form air-permeable through holes, the air-permeable through holes penetrate the flexible conductive layer and the flexible insulating layer, and the elastomer is peeled off from the rigid base layer to obtain a flexible electrode.

6. The method for preparing a flexible electrode according to claim 5, characterized in that: In step (3), after the electrode layer is generated, a wire connection portion is placed at a position of the electrode layer, and the wire connection portion is covered by a flexible insulating layer.

7. The method for preparing a flexible electrode according to claim 5, characterized in that: In step (3), the electrode layer is grown by sputtering.

8. A flexible electrode material, characterized in that: An elastomer for a flexible electrode according to any one of claims 1 to 5, wherein the elastomer comprises a flexible conductive layer and a flexible insulating layer; the flexible conductive layer comprises polydimethylsiloxane, polydopamine, carboxylated cellulose nanofibers and conductive carbon black; The flexible insulating layer comprises polydimethylsiloxane, carboxylated cellulose nanofibers and polyurethane resin.

9. A flexible electrode material according to claim 8, characterized in that: The flexible conductive layer comprises, by weight, 60 to 67 parts of polydimethylsiloxane, 27 to 32 parts of carboxylated cellulose nanofibers, 8 to 12 parts of polydopamine and 6 to 9 parts of conductive carbon black; The flexible insulating layer comprises, by weight, 60 to 67 parts of polydimethylsiloxane, 32 to 37 parts of carboxylated cellulose nanofibers and 10 to 15 parts of polyurethane resin.

10. The flexible electrode material according to claim 8, characterized in that: The diameter of the carboxylated cellulose nanofiber is 4-10 nm, and the length is 100-200 nm; the particle size of the polydopamine is 100-150 nm; and the particle size of the conductive carbon is less than 30 nm.

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