High-flexibility stretchable transparent electrode and preparation method and application thereof

Abstract

The invention provides a high-flexibility stretchable transparent electrode and a preparation method and application thereof, and belongs to the technical field of flexible electrodes. The method comprises the following steps: spin-coating a metal nanowire dispersion liquid on the surface of a glass substrate to form a conductive film; spin-coating a polyrotaxane solution containing double bonds to form a PRA film; coating the elastomer precursor solution to form an elastic substrate; and after curing, stripping the elastic substrate from the glass substrate to prepare the high-flexibility stretchable transparent electrode. The method can be used for an electroluminescent device, a flexible touch screen and wearable flexible electronic equipment for detecting physiological electric signals of a human body. According to the invention, the metal nanowire is used as a conductive material, and isocyanate-modified polyrotaxane PRA is used as a cross-linking agent to be introduced into the nanowire and a transparent elastic substrate; when the electrode is stretched, cyclodextrin in the PRA can freely move on a polyethylene glycol long chain, and the stress concentration problem is effectively relieved, so that the fracture of the nanowire is reduced, the working range of the transparent electrode is widened, and the change rate of resistance is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible electrodes, and particularly relates to a highly flexible and stretchable transparent electrode, its preparation method and uses. Background Art

[0002] Stretchable electronic devices have received extensive attention due to their potential applications in fields such as wearable sensors, electronic skin, and artificial intelligence. As one of the important components of flexible electronic devices, transparent stretchable electrodes play a crucial role in the electronic conductive layers and windows of touch screen displays, solar cells, wearable electronics, and communication devices. Metal nanowires, especially silver nanowires, have become the most promising choice for stretchable transparent electrodes due to their significant advantages such as low cost, excellent mechanical flexibility, high optical transmittance, low sheet resistance, and easy processing.

[0003] The basic composition of a stretchable transparent electrode is a stretchable transparent elastic substrate and a conductive material. Currently, there are mainly two problems in preparing high-performance stretchable transparent electrodes: (1) the mechanical mismatch between the conductive material and the substrate; (2) the inherent contradiction between high light transmittance and low resistance, and between low resistance and high stretchability.

[0004] The reason for the mechanical mismatch is that the elongation at break of the elastic substrate is much higher than that of the conductive element. Under certain strain conditions, the conductive material will separate from the elastic substrate, and then be damaged and finally lose its conductivity. The mechanical mismatch between metal nanowires and flexible substrates leads to stress concentration problems at the interface of transparent stretchable electrodes, causing the nanowires to break and fall off, thus affecting the stretchability and electrical stability of the electrodes. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a highly flexible and stretchable transparent electrode based on metal nanowires and its preparation method, aiming to solve at least one of the technical problems in the background art.

[0006] The present invention is implemented as follows:

[0007] A preparation method of a highly flexible and stretchable transparent electrode, which comprises the following steps:

[0008] Provide a glass substrate;

[0009] Spin-coat a metal nanowire dispersion on the surface of the glass substrate to form a conductive thin film;

[0010] Spin-coat a polyrotaxane solution containing double bonds on the surface of the conductive thin film to form a PRA thin film;

[0011] Coat an elastomer precursor solution on the surface of the PRA thin film to form an elastic substrate;

[0012] After curing, the elastic substrate is peeled off from the glass substrate to obtain a highly flexible and stretchable transparent electrode;

[0013] Among them, the synthesis method of the polyrotaxane containing double bonds is as follows: Prepare a pseudo-polyrotaxane using hydroxypropyl-α-cyclodextrin and polyethylene glycol diamine as raw materials; Use 3-hydroxy-1-adamantane carboxylic acid and 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride as capping agents, and react with the pseudo-polyrotaxane to obtain a capped polyrotaxane; Use 2-acryloyloxyethyl isocyanate to bond with the hydroxyl groups on the cyclodextrin in the capped polyrotaxane to form a polyrotaxane containing double bonds.

[0014] Preferably, the synthesis method of the polyrotaxane containing double bonds includes the following steps:

[0015] First, add hydroxypropyl-α-cyclodextrin and polyethylene glycol diamine to PBS buffer solution, stir at room temperature until completely dissolved, and let the solution stand in the refrigerator for at least 48 h to obtain a pseudo-polyrotaxane;

[0016] Add 3-hydroxy-1-adamantane carboxylic acid and 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride to the pseudo-polyrotaxane, stir at room temperature for at least 24 h for the capping reaction;

[0017] Add 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride again, stir at room temperature and continue to react for at least 24 h. After the reaction, dialyze and freeze-dry the mixture to obtain a capped polyrotaxane;

[0018] Dissolve 2-acryloyloxyethyl isocyanate in anhydrous dimethyl sulfoxide to form solution A; Dissolve butylhydroxytoluene, dibutyltin dilaurate and the capped polyrotaxane in anhydrous dimethyl sulfoxide to form solution B; Under the conditions of light avoidance and oxygen-free, drop solution A into solution B, stir evenly and then heat and react overnight; After the reaction, add an excessive amount of methanol, and successively carry out cooling and standing precipitation, dialysis, and freeze-drying to obtain a polyrotaxane containing double bonds.

[0019] Preferably, the threading rate of cyclodextrin in the pseudo-polyrotaxane is 1%-10%; the molecular weight of polyethylene glycol diamine is 5000-200000;

[0020] In the process of synthesizing the polyrotaxane containing double bonds, the dosage of hydroxypropyl-α-cyclodextrin is 0.063 - 0.65 mol / L; the dosage of polyethylene glycol diamine is 4.3 mmol / L; the molar ratio of the quasi-polyrotaxane, 3-hydroxy-1-adamantane carboxylic acid, and the first addition of 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride is 1:39:60; the dosage of the second addition of 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride is 0.2 mol / L; the molar ratio of 2-acryloyloxyethyl isocyanate, butylhydroxytoluene, dibutyltin dilaurate, and the capped polyrotaxane is 120:1:10:5.

[0021] Preferably, the metal nanowires are selected from at least one of gold nanowires, silver nanowires, and copper nanowires.

[0022] Preferably, the concentration of the metal nanowire dispersion is 1 mg / mL - 10 mg / mL; the diameter of the metal nanowires is 10 nm - 300 nm, and the length is 3 μm - 300 μm; the number of spin-coated layers of the metal nanowire dispersion is 1 - 10 layers.

[0023] Preferably, the concentration of the polyrotaxane solution containing double bonds is 0.1 mg / mL - 1 mg / mL, and the number of spin-coated layers of the polyrotaxane solution containing double bonds is 1 - 10 layers.

[0024] Preferably, the elastomer precursor solution includes polyurethane, acrylic acid (5-ethyl-1,3-dioxan-5-yl) methyl ester, and a photoinitiator.

[0025] Preferably, the photoinitiator is one of photoinitiator TPO, photoinitiator 1173, photoinitiator 184, and photoinitiator 2959.

[0026] The second aspect of the present invention provides the highly flexible and stretchable transparent electrode prepared by the above preparation method.

[0027] The third aspect of the present invention provides the use of the highly flexible and stretchable transparent electrode prepared by the above preparation method, which is applied to electroluminescent devices, flexible touch screens, and wearable flexible electronic devices for detecting human physiological electrical signals.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. In the present invention, metal nanowires are used as the conductive material, and polyrotaxane PRA modified with isocyanate is introduced into the nanowires and the transparent elastic substrate; when the electrode is stretched, the cyclodextrin in PRA can move freely on the polyethylene glycol long chain, effectively alleviating the stress concentration problem, thereby reducing the fracture of the nanowires, broadening the working range of the transparent electrode, and reducing the change rate of resistance.

[0030] 2. The highly flexible metal nanowire stretchable transparent electrode prepared by the present invention has characteristics such as high transparency, large working range, high stability, and insensitivity to strain.

[0031] 3. In the stretchable transparent electrode of the present invention, various forces such as covalent bonds, ionic bonds, hydrogen bonds, and van der Waals forces are formed between the metal nanowires and the cyclodextrins in the polyrotaxane, and between the elastic substrate and the polyrotaxane, effectively improving the stretchability and electrical stability of the electrode. Brief Description of the Drawings

[0032] Figure 1 is a schematic structural diagram of the highly flexible stretchable transparent electrode of the present invention;

[0033] Figure 2 is a corresponding curve graph of the sheet resistance and light transmittance of the highly flexible stretchable transparent electrode prepared in Example 1 of the present invention;

[0034] Figure 3 is a working curve graph of the highly flexible stretchable transparent electrode prepared in Example 1 of the present invention;

[0035] Figure 4 is a SEM image of the highly flexible stretchable transparent electrodes prepared in Example 1 and Comparative Example 1 of the present invention under strain. Detailed Embodiments

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] A preparation method of a highly flexible stretchable transparent electrode includes the following steps S1 to S4.

[0038] S1. Raw material preparation

[0039] (1) Prepare a metal nanowire dispersion

[0040] Mix metal nanowires with a diameter of 10 nm to 300 nm and a length of 3 μm to 300 μm in an organic solvent such as methanol, ethanol, isopropanol, or dichloromethane to form a metal nanowire dispersion with a concentration of 1 mg / mL to 10 mg / mL;

[0041] In specific implementation, the metal nanowires are selected from at least one of gold nanowires, silver nanowires, and copper nanowires;

[0042] (2) Prepare a polyrotaxane containing double bonds

[0043] Hydroxypropyl-α-cyclodextrin (HP-α-CD) and polyethylene glycol diamine (NH 2 -PEG-NH 2 ) were added to PBS buffer solution and stirred at room temperature for 1 h to completely dissolve them. The solution was left standing in the refrigerator for more than 2 days to react, and a pseudo-polyrotaxane was prepared; the threading rate of cyclodextrin in the pseudo-polyrotaxane was 1%-10%, and the molecular weight of polyethylene glycol diamine was 5000-200000;

[0044] Then, 3-hydroxy-1-adamantane carboxylic acid and 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride (DMTMM) were added to the pseudo-polyrotaxane for end-capping and stirred at room temperature for 1 day; DMTMM was added again and the reaction continued at room temperature for another day; the mixture was dialyzed for 2 days and freeze-dried to obtain the end-capped polyrotaxane PR;

[0045] 2-Acryloyloxyethyl isocyanate was dissolved in anhydrous dimethyl sulfoxide to form solution A; butylated hydroxytoluene, dibutyltin dilaurate and the end-capped polyrotaxane were mixed and dissolved in anhydrous dimethyl sulfoxide to form solution B; under light-shielded and oxygen-free conditions, solution A was added dropwise to solution B, stirred vigorously and uniformly, and then heated and reacted overnight. In this process, the hydroxyl groups on the cyclodextrin in the polyrotaxane could form ester bonds with the isocyanate groups. After the reaction, an excess of methanol was added, and the mixture was left standing in the refrigerator for precipitation. The precipitate was dialyzed with deionized water for three days and then freeze-dried to obtain the polyrotaxane PRA containing double bonds;

[0046] In specific embodiments, the dosage of hydroxypropyl-α-cyclodextrin was 0.063 mol / L - 0.65 mol / L, and 0.064 mol / L was selected in the following examples; however, it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable; the dosage of polyethylene glycol diamine was 4.3 mmol / L; the molar ratio of the pseudo-polyrotaxane, 3-hydroxy-1-adamantane carboxylic acid, and the first addition of 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride was 1:39:60; the dosage of the second addition of 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride was 0.2 mol / L; the molar ratio of 2-acryloyloxyethyl isocyanate, butylated hydroxytoluene, dibutyltin dilaurate, and the end-capped polyrotaxane was 120:1:10:5.

[0047] (3) Preparation of elastomer precursor solution

[0048] Polyurethane, acrylic acid (5-ethyl-1,3-dioxan-5-yl) methyl ester and a photoinitiator were uniformly mixed and centrifuged to remove bubbles, and a transparent elastic precursor solution was prepared;

[0049] The photoinitiator is one of photoinitiator TPO (diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide), photoinitiator 1173 (2-hydroxy-2-methyl-1-phenyl-1-propanone), photoinitiator 184 (1-hydroxycyclohexyl phenyl ketone), and photoinitiator 2959 (2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone). Photoinitiator TPO is selected in the following examples, but it is not limited to the listed photoinitiators, and other unlisted photoinitiators are also applicable.

[0050] S2. Preparation of the conductive thin film

[0051] The metal nanowire dispersion liquid prepared in step S1 is spin-coated on the surface of a clean glass substrate, and the number of spin-coated layers is 1 to 10 layers. After heating and curing, a conductive thin film is formed.

[0052] S3. Preparation of the PRA thin film

[0053] The polyrotaxane PRA containing double bonds prepared in step S1 is configured into a PRA solution with a concentration of 0.1 mg / mL to 1 mg / mL; it is spin-coated on the surface of the conductive thin film, and the number of spin-coated layers is 1 to 10 layers to form a PRA thin film.

[0054] S4. Preparation of the elastic substrate

[0055] The elastomer precursor solution prepared in step S1 is evenly spread on the surface of the PRA thin film to prepare an elastic substrate. After curing, it is peeled off to obtain a highly flexible and stretchable transparent electrode, and its structure is as Figure 1 shown.

[0056] In Figure 1 the left side is the schematic diagram of the structure of the highly flexible and stretchable transparent electrode, and the right side is the enlarged cross-sectional view of the stretchable transparent electrode. From top to bottom, they are: conductive thin film (MNWs), PRA thin film (PRA), and elastic substrate (PU). Covalent bonds, ionic bonds, hydrogen bonds, van der Waals forces, and other interactions are formed between the metal nanowires and the cyclodextrin in the polyrotaxane, and between the elastic substrate and the polyrotaxane. The hydroxyl groups on the cyclodextrin in the polyrotaxane can form ester bonds with isocyanate groups, enabling the polyrotaxane to crosslink to form a network; when the electrode is stretched, the cyclodextrin in the PRA can move freely on the polyethylene glycol long chain, effectively alleviating the stress concentration problem, thereby reducing the fracture of the metal nanowires.

[0057] The highly flexible and stretchable transparent electrode is applied to electroluminescent devices, flexible touch screens, and wearable flexible electronic devices for detecting human physiological electrical signals.

[0058] Example 1

[0059] This Example 1 is a preparation method of a highly flexible and stretchable transparent electrode, which is specifically as follows:

[0060] Step 1: Select a 1 mg / ml silver nanowire dispersion solution. Use spin coating to evenly spread the conductive material on the surface of the glass slide. The number of spin coating layers is 10 layers. Heat at 120 °C for 3 min to obtain a silver nanowire conductive film.

[0061] Step 2: Add hydroxypropyl-α-cyclodextrin (HP-α-CD) and polyethylene glycol diamine 20000 (NH 2 -PEG-NH 2 ) into the PBS buffer solution. Stir at room temperature for 1 h to completely dissolve it. Let the solution stand in the refrigerator for more than 2 days to react to obtain a quasi-polyrotaxane. Then add 3-hydroxy-1-adamantane carboxylic acid and 4-(4,6-dimethoxytriazin-2-yl)-4-methylmorpholine hydrochloride (DMTMM) to the above mixture for end-capping. Stir at room temperature for 1 day. Add DMTMM again, and the reaction continues at room temperature for another day. Dialyze the mixture for 2 days and freeze-dry to obtain the end-capped polyrotaxane PR. Dissolve butylated hydroxytoluene BHT, dibutyltin dilaurate DBTDL, and polyrotaxane PR in anhydrous dimethyl sulfoxide DMSO. Under the conditions of avoiding light and oxygen, dropwise add 2-acryloyloxyethyl isocyanate pre-dissolved in anhydrous dimethyl sulfoxide to the above solution and stir vigorously. Heat and stir the solution overnight. The hydroxyl group on the cyclodextrin in the polyrotaxane can form an ester bond with the isocyanate group. After the reaction, add an excess of methanol, let it stand and precipitate in the refrigerator, dialyze the precipitate with deionized water for three days, and then perform freeze-drying to obtain the polyrotaxane PRA containing double bonds. Prepare a 1 mg / ml PRA solution, and spin coat it onto the silver nanowire conductive film at a rotation speed of 700 rpm for 20 s. The number of spin coating layers is 1 layer to form an AgNWs / PRA film.

[0062] Step 3: Weigh 4 g of polyurethane 6210, 1 g of acrylic acid (5-ethyl-1,3-dioxan-5-yl) methyl ester, and 0.15 g of photoinitiator and mix them evenly to obtain an elastomer precursor solution. Centrifuge (5000 rpm, 5 min) to remove air bubbles. Spread the elastomer precursor solution evenly on the surface of the AgNWs / PRA film. After curing, peel it off to obtain a highly flexible and stretchable transparent electrode.

[0063] Example 2

[0064] The difference between this Example 2 and Example 1 is that in Step 1, the material of the conductive film is copper nanowires, and the other steps and conditions are the same as those in Example 1.

[0065] Example 3

[0066] The difference between this Example 3 and Example 1 is that in Step 1, the material of the conductive film is gold nanowires, and the other steps and conditions are the same as those in Example 1.

[0067] Example 4

[0068] The difference between this Example 4 and Example 1 is that the number of spin-coated layers of the PRA solution in step 2 is 2 layers, and the other steps and conditions are the same as those in Example 1.

[0069] Example 5

[0070] The difference between this Example 5 and Example 1 is that the number of spin-coated layers of the PRA solution in step 2 is 6 layers, and the other steps and conditions are the same as those in Example 1.

[0071] Example 6

[0072] The difference between this Example 6 and Example 1 is that the number of spin-coated layers of the PRA solution in step 2 is 10 layers, and the other steps and conditions are the same as those in Example 1.

[0073] Example 7

[0074] The difference between this Example 7 and Example 1 is that the number of spin-coated layers of the silver nanowire dispersion in step 1 is 5 layers, and the other steps and conditions are the same as those in Example 1.

[0075] Example 8

[0076] The difference between this Example 8 and Example 1 is that the number of spin-coated layers of the silver nanowire dispersion in step 1 is 1 layer, and the other steps and conditions are the same as those in Example 1.

[0077] Example 9

[0078] The difference between this Example 9 and Example 1 is that the molecular weight of the polyethylene glycol diamine in step 2 is adjusted to 200000, and the other steps and conditions are the same as those in Example 1.

[0079] Example 10

[0080] The difference between this Example 10 and Example 1 is that the molecular weight of the polyethylene glycol diamine in step 2 is adjusted to 5000, and the other steps and conditions are the same as those in Example 1.

[0081] Comparative Example 1

[0082] This Comparative Example 1 prepares a stretchable transparent electrode, and the difference from Example 1 is that: step 2 is deleted, there is no PRA film, and the other steps and conditions are the same as those in Example 1.

[0083] Comparative Example 2

[0084] This Comparative Example 2 prepares a stretchable transparent electrode, and the difference from Example 1 is that: in step 2, the spin-coated solution is a capped polyrotaxane solution instead of a polyrotaxane solution containing double bonds, and the PRA film becomes a PR film, and the other steps and conditions are the same as those in Example 1.

[0085] The number of layers of the silver nanowire conductive film in Example 1 was adjusted to: 10 layers, 20 layers, 40 layers, and 80 layers respectively; the corresponding curves of the sheet resistance and light transmittance of the highly flexible and stretchable transparent electrode are as Figure 2 shown, and from Figure 2 it can be seen that as the amount of nanowires increases, the sheet resistance of the transparent electrode decreases and the light transmittance decreases;

[0086] The working curve of the highly flexible and stretchable transparent electrode prepared in Example 1 back and forth is as Figure 3 shown, that is, the change of resistance with the change of the working range. From Figure 3 it can be seen that the resistance change rate of the transparent electrode is only 60% within a large working range of 130%;

[0087] The SEM images of the highly flexible and stretchable transparent electrodes prepared in Example 1 and Comparative Example 1 under strain are as Figure 4 shown. From Figure 4 it can be seen that under 50% stretching, the electrode in Comparative Example 1 suffered obvious fracture, while the electrode in Example 1 did not fracture.

[0088] Taking the stretchable transparent electrodes prepared in Example 1 to Example 10, Comparative Example 1 and Comparative Example 2 as samples for performance testing, the results are shown in Table 1, specifically including:

[0089] (1) Sheet resistance;

[0090] The test method is to test the sheet resistance of the stretchable transparent electrode using a four-probe test system: then calculate the conductivity of the stretchable transparent electrode using the formula conductivity = 1 / (sheet resistance * electrode thickness), and further judge the conductivity of the stretchable transparent electrode. It can be seen from the formula that the smaller the sheet resistance, the better the conductivity.

[0091] (2) Light transmittance:

[0092] The test method is to test the light transmittance of the stretchable transparent electrode using an ultraviolet-visible spectrophotometer;

[0093] (3) Working range

[0094] The test method is to perform a stretching test on the stretchable transparent electrode using a reciprocator and a source meter, record the maximum stretching length and resistance change rate that the sample withstands during the stretching process, and calculate the working range based on the recorded data.

[0095] (4) Bending stability

[0096] Fix the stretchable transparent electrode sample on a bending fixture and bend it 1000 times, then test the sheet resistance and light transmittance of the sample after bending, and calculate the change situation.

[0097] (5) Tensile stability

[0098] Mount the stretchable transparent electrode sample on the fixture of a material testing machine. After starting, stretch the sample uniformly at a set rate, and test the sheet resistance and light transmittance of the sample when the stretch ratio is 50%, and calculate the change situation.

[0099] Table 1

[0100]

[0101]

[0102] It can be seen from the data in Table 1 that the stretchable transparent electrodes prepared in Examples 1 to 10 of the present invention have high conductivity, high light transmittance, and a working range of 50%-150%.

[0103] It can be seen from Examples 1 to 3 that gold, silver, and copper nanowires can be used as conductive materials to prepare highly flexible and high-performance stretchable transparent electrodes.

[0104] It can be seen from the comparison of Examples 1, 4 to 6 that as the number of PRA film layers increases, its sheet resistance increases, the light transmittance decreases, and the working range, bending stability, and stretching stability all decrease. This is because as the amount of PRA increases, PRA agglomerates, affecting the optoelectronic properties and working range of the transparent electrode.

[0105] It can be seen from the comparison of Examples 1, 7 to 8 that as the number of metal nanowire conductive film layers increases, its sheet resistance decreases, the light transmittance decreases, the working range increases, the bending stability increases, and the stretching stability increases.

[0106] It can be seen from the comparison of Examples 1, 9 to 10 that as the molecular weight of polyethylene glycol diamine increases, its sheet resistance decreases, the light transmittance increases, the working range increases, the bending stability increases, and the stretching stability increases. This is because as the molecular weight of polyethylene glycol diamine increases, the moving range of cyclodextrin during stretching increases, reducing the breakage of nanowires and increasing the stretching range and stability of the electrode.

[0107] It can be seen from the comparison of Examples 1, Comparative Example 1 and Comparative Example 2 that the electrodes without PRA film and the electrodes of conventional polyrotaxane have lower conductivity, light transmittance, and stability than Example 1, and the metal nanowires are more likely to break and fall off.

[0108] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A method for preparing a highly flexible stretchable transparent electrode, characterized in that: The preparation method comprises the following steps: providing a glass substrate; Spin coating the metal nanowire dispersion onto the surface of the glass substrate to form a conductive film; Spin coating a polyrotaxane solution containing double bonds on the surface of the conductive film to form a PRA film; Coating an elastomer precursor liquid on the surface of the PRA film to form an elastic substrate; After curing, the elastic substrate is peeled off from the glass substrate to obtain a highly flexible and stretchable transparent electrode; Among them, the synthesis method of the polyrotaxane containing a double bond is as follows: hydroxypropyl-α-cyclodextrin and polyethylene glycol diamine are used as raw materials to prepare a pseudo-polyrotaxane; 3-hydroxy-1-adamantanecarboxylic acid and 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride are used as capping agents to react with the pseudo-polyrotaxane to obtain a blocked polyrotaxane; 2-acryloyloxyethyl isocyanate is used to bond with the hydroxyl group on the cyclodextrin in the blocked polyrotaxane to form a polyrotaxane containing a double bond.

2. The method for preparing a highly flexible stretchable transparent electrode according to claim 1, characterized in that: The synthesis method of the double-bond-containing polyrotaxane comprises the following steps: First, hydroxypropyl-α-cyclodextrin and polyethylene glycol diamine were added to a PBS buffer solution, stirred at room temperature to completely dissolve them, and the solution was allowed to stand in a refrigerator to react for at least 48 hours to obtain a pseudopolyrotaxane; Add 3-hydroxy-1-adamantanecarboxylic acid and 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride to the pseudopolyrotaxane and stir at room temperature for at least 24 hours to perform a capping reaction; 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride was added again, and the reaction was continued with stirring at room temperature for at least 24 hours. After the reaction was completed, the mixture was dialyzed and freeze-dried to obtain a capped polyrotaxane; 2-Acryloyloxyethyl isocyanate is dissolved in anhydrous dimethyl sulfoxide to form a solution A; butylated hydroxytoluene, dibutyltin dilaurate and the blocked polyrotaxane are mixed and dissolved in anhydrous dimethyl sulfoxide to form a solution B; in a light-proof and oxygen-free condition, solution A is added dropwise to solution B, stirred evenly, and then heated to react overnight; after the reaction is completed, excess methanol is added, and the solution is cooled, allowed to stand for precipitation, dialyzed, and freeze-dried in sequence to obtain a polyrotaxane containing a double bond.

3. The method for preparing a highly flexible stretchable transparent electrode according to claim 2, characterized in that: The threading rate of cyclodextrin in the pseudopolyrotaxane is 1%-10%; the molecular weight of polyethylene glycol diamine is 5000-200000; In the process of synthesizing a polyrotaxane containing a double bond, the amount of hydroxypropyl-α-cyclodextrin used is 0.063 mol / L-0.65 mol / L; the amount of polyethylene glycol diamine used is 4.3 mmol / L; the molar ratio of the pseudo-polyrotaxane, 3-hydroxy-1-adamantanecarboxylic acid, and the first addition of 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride is 1:39:60; the amount of the second addition of 4-(4,6-dimethoxytriazine-2-yl)-4-methylmorpholine hydrochloride is 0.2 mol / L; the molar ratio of 2-acryloyloxyethyl isocyanate, butylhydroxytoluene, dibutyltin dilaurate, and the end-capped polyrotaxane is 120:1:10:

5.

4. The method for preparing a highly flexible stretchable transparent electrode according to claim 1, characterized in that: The metal nanowire is selected from at least one of gold nanowire, silver nanowire and copper nanowire.

5. The method for preparing a highly flexible stretchable transparent electrode according to claim 4, characterized in that: The concentration of the metal nanowire dispersion is 1 mg / mL to 10 mg / mL; the diameter of the metal nanowire is 10 nm to 300 nm, and the length is 3 μm to 300 μm; the number of spin-coated layers of the metal nanowire dispersion is 1 to 10 layers.

6. The method for preparing a highly flexible stretchable transparent electrode according to claim 1, characterized in that: The concentration of the polyrotaxane solution containing double bonds is 0.1 mg / mL to 1 mg / mL, and the number of spin-coated layers of the polyrotaxane solution containing double bonds is 1 layer to 10 layers.

7. The method for preparing a highly flexible stretchable transparent electrode according to claim 1, characterized in that: The elastomer precursor liquid comprises polyurethane, methyl acrylate (5-ethyl-1,3-dioxane-5-yl) and a photoinitiator.

8. The method for preparing a highly flexible stretchable transparent electrode according to claim 7, characterized in that: The photoinitiator is one of photoinitiator TPO, photoinitiator 1173, photoinitiator 184, and photoinitiator 2959.

9. A highly flexible stretchable transparent electrode prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the highly flexible stretchable transparent electrode prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The highly flexible stretchable transparent electrode is applied to electroluminescent devices, flexible touch screens, and wearable flexible electronic devices for detecting physiological electrical signals of the human body.

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