阅读说明：本技术 一种全柔性透明薄膜电极及其制备方法和应用 (Fully flexible transparent film electrode and preparation method and application thereof ) 是由 赖文勇 牛坚 李冠军 于 2021-07-30 设计创作，主要内容包括：本发明涉及柔性电极技术领域,具体涉及一种全柔性透明薄膜电极及其制备方法和应用。所述为全柔性透明薄膜电极,由水溶性聚合物作为掺杂物和导电聚合物共混构成；制备方法包括：将水溶性聚合物溶解于极性有机溶剂中,加热搅拌后和PEDOT:PSS溶液搅拌混匀得到全柔性透明薄膜溶液,然后滴涂到基底上,通过旋涂、刮涂或者丝网印刷在基底上制备全柔性透明薄膜；全柔性透明薄膜连同基底退火干燥后转移至水中,超声处理使全柔性透明薄膜和基底分离,得到全柔性透明薄膜电极。本发明提供了一种全柔性透明薄膜电极,制备的全柔性透明薄膜电极具有良好的导电性和透明度,同时具有良好的机械性能,可承受一定程度的应变。(The invention relates to the technical field of flexible electrodes, in particular to a fully flexible transparent film electrode and a preparation method and application thereof. The electrode is a fully flexible transparent film electrode and is formed by blending a water-soluble polymer serving as a dopant and a conductive polymer; the preparation method comprises the following steps: dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution and PEDOT, namely PSS solution, uniformly stirring the solution and the PEDOT solution to obtain a fully flexible transparent film solution, then dripping the fully flexible transparent film solution on a substrate, and preparing a fully flexible transparent film on the substrate by spin coating, blade coating or screen printing; and (3) annealing and drying the fully flexible transparent film and the substrate, transferring the fully flexible transparent film and the substrate into water, and separating the fully flexible transparent film from the substrate by ultrasonic treatment to obtain the fully flexible transparent film electrode. The invention provides a fully flexible transparent film electrode, which has good conductivity and transparency, good mechanical properties and can bear strain to a certain degree.)

1. The fully flexible transparent film electrode is a fully polymer-based flexible transparent conductive electrode and is formed by blending a water-soluble polymer serving as a dopant and a conductive polymer;

PSS, and the water-soluble polymer is a hydrophilic high-molecular polymer with hydroxyl.

2. The fully flexible transparent thin film electrode according to claim 1, wherein the water-soluble polymer is one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer, or hydrophilic polyurethane; the molecular weight of the water-soluble polymer is 2500-; the mass ratio of the water-soluble polymer to the conductive polymer is 0-0.83: 1, wherein 0 is not included.

3. A method for preparing a fully flexible transparent thin film electrode according to any one of claims 1-2, comprising the steps of:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a conductive polymer solution to obtain a fully flexible transparent film solution;

(2) dripping the fully flexible transparent film solution on a substrate, and preparing a fully flexible transparent film on the substrate by spin coating, blade coating or screen printing;

(3) and (3) annealing and drying the fully flexible transparent film and the substrate, transferring the fully flexible transparent film and the substrate into water, and separating the fully flexible transparent film from the substrate by ultrasonic treatment to obtain the fully flexible transparent film electrode.

4. The method for preparing a fully flexible transparent thin film electrode according to claim 3,

in the step (1): the polar organic solvent is one or more of acetonitrile, acetone, dichloromethane, dimethylformamide, methanol, ethanol and glycol; the mass concentration of the water-soluble polymer in the polar organic solvent is 1-10 mg/mL, and the heating and stirring are specifically stirring at the rotating speed of 300-1000 rpm/min at 60 ℃; the water-soluble polymer and PEDOT: the mass ratio of the PSS is 0-0.83: 1, wherein 0 is not included.

In the step (2): the substrate is a flexible substrate or a rigid substrate, the flexible substrate is one of polyethylene terephthalate (PET), Polyimide (PI) or Polydimethylsiloxane (PDMS), and the rigid substrate is one of a glass sheet, a silicon wafer and a quartz sheet; the spin coating specifically comprises the following steps: spin coating at 800-80000 rpm/min for 30-60 s; the blade coating specifically comprises the following steps: the distance between the scraper and the substrate is 0.1-1.2 mm, and the scraping speed of the scraper is 0.05-5 cm/s; the silk-screen printing specifically comprises the following steps: a 100-600 mesh screen is used.

In the step (3): the annealing and drying temperature is 25-200 ℃, and the time is 1-3 h; the ultrasonic power is 10-100W, and the ultrasonic time is 20-60 s.

5. Use of a fully flexible transparent thin film electrode according to any one of claims 1-2 for the preparation of flexible electronic, optoelectronic or electronic devices.

6. A flexible electronic device comprising a fully flexible transparent thin film electrode according to any one of claims 1-2; the flexible electronic device is a flexible wearable sensor, a flexible light emitting diode or a flexible supercapacitor.

7. A method for preparing the flexible electronic device according to claim 6, wherein when the flexible electronic device is a flexible wearable sensor, the method comprises the following steps:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a PEDOT (PSS) solution to obtain a fully flexible transparent film solution;

(2) spin-coating the fully flexible transparent film solution on one surface of PDMS subjected to oxygen plasma treatment, and annealing and drying;

(3) and (3) repeating the step (2) to prepare a fully flexible transparent film on the other surface of the PDMS subjected to the oxygen plasma treatment to obtain the flexible wearable sensor.

8. The method for manufacturing the flexible electronic device according to claim 6, wherein when the flexible electronic device is a flexible light emitting diode, the method comprises the following steps:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a PEDOT (PSS) solution to obtain a fully flexible transparent film solution;

(2) spin-coating the fully flexible transparent film solution on the PET substrate subjected to ultraviolet treatment, and annealing and drying to obtain a fully flexible transparent film electrode;

(3) putting the fully flexible transparent film electrode into an evaporation device, and carrying out evaporation in sequence according to the sequence of N, N '-di (1-naphthyl) -N, N' -diphenyl- (1,1 '-biphenyl) -4,4' -diamine (NPB) (60 nm)/tris (8-hydroxyquinoline) aluminum (Alq3) (60 nm)/lithium fluoride (1 nm)/aluminum (80nm) and the film thickness to obtain the flexible light-emitting diode.

9. The method for preparing the flexible electronic device according to claim 6, wherein when the flexible electronic device is a flexible supercapacitor, the method comprises the following steps:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a PEDOT (PSS) solution to obtain a fully flexible transparent film solution;

(2) spin-coating the fully flexible transparent film solution on the PDMS subjected to ultraviolet treatment, and annealing and drying to obtain a fully flexible transparent film electrode;

(3) and assembling the fully flexible transparent film electrode and the hydrogel electrolyte to obtain the flexible supercapacitor.

10. The method for manufacturing a flexible electronic device according to any one of claims 7 to 9, wherein the polar organic solvent in step (1) is one or more of acetonitrile, acetone, dichloromethane, dimethylformamide, methanol, ethanol, ethylene glycol; the mass concentration of the water-soluble polymer in the polar organic solvent is 1-10 mg/mL, and the heating and stirring are specifically stirring at the rotating speed of 300-1000 rpm/min at 60 ℃; the water-soluble polymer and PEDOT: the mass ratio of the PSS is 0-0.83: 1, excluding 0;

the spin coating in the step (2) is carried out at the speed of 2000r/min, and the annealing and drying are specifically carried out at the temperature of 110 ℃ for 10 min.

Technical Field

The invention relates to the technical field of flexible electrodes, in particular to a fully flexible transparent film electrode and a preparation method and application thereof.

Background

Flexible electronic products have been rapidly developed in the last decade, and the development trend of flexible and light-weight electronic devices has made flexible electronic devices closer to practical applications. Transparent Conductive Electrodes (TCEs) are widely used as basic elements in flexible electronic devices, such as Organic Light Emitting Diodes (OLEDs), Organic Solar Cells (OSCs), and flexible touch panels. For conventional electronic devices, Indium Tin Oxide (ITO) is generally used to prepare TCEs, but the shortages of brittle texture and high production cost limit further application of the material in flexible electronic devices. In view of the above problems, extensive research on conductive materials (such as single-walled carbon nanotubes, graphene, metal meshes, and metal nanowires) having bending resistance has been conducted. In general, one-dimensional materials with high aspect ratios (e.g., silver nanowires) are considered the most promising materials for the preparation of flexible TCEs due to their high conductivity, transparency, and flexibility. However, the silver nanowire network generally has high roughness, and is easy to penetrate through an active layer of an optoelectronic device, thereby causing overlarge leakage current and even short circuit, and further causing poor device performance. In addition, due to the lack of electrochemical performance, silver nanowires can only be used as current collectors of flexible energy storage devices, but not as electrodes, so that the universality of the application of the silver nanowires as the electrodes is limited. These problems also arise when other conductive materials are used as TCEs.

In summary, although the prior art has proposed solutions such as embedding a conductive network in an elastomer to improve its roughness, the complexity and non-uniformity of the process still prevents its further application. Therefore, it is still an urgent problem to develop a universal transparent conductive electrode suitable for various flexible electronic products.

Disclosure of Invention

Aiming at the defects and improvement requirements of the prior art, the invention provides the fully flexible transparent film electrode, and the prepared fully flexible transparent film electrode has good conductivity and transparency, and simultaneously has good mechanical properties and can bear strain to a certain degree.

One of the technical schemes of the invention is that the full-flexible transparent film electrode is a full-polymer-based flexible transparent conductive electrode and is formed by blending a water-soluble polymer serving as a dopant and a conductive polymer;

PSS, and the water-soluble polymer is a hydrophilic high-molecular polymer with hydroxyl; the water-soluble polymer is one or more of polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer or hydrophilic polyurethane.

Further, the molecular weight of the water-soluble polymer is 2500-; the mass ratio of the water-soluble polymer to the conductive polymer is 0-0.83: 1, wherein 0 is not included.

In the second technical scheme of the invention, the preparation method of the fully flexible transparent film electrode comprises the following steps:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a conductive polymer solution to obtain a fully flexible transparent film solution;

(2) dripping the fully flexible transparent film solution on a substrate, and preparing a fully flexible transparent film on the substrate by spin coating, blade coating or screen printing;

(3) and (3) annealing and drying the fully flexible transparent film and the substrate, transferring the fully flexible transparent film and the substrate into water, and separating the fully flexible transparent film from the substrate by ultrasonic treatment to obtain the fully flexible transparent film electrode.

Further, in the step (1): the polar organic solvent is one or more of acetonitrile, acetone, dichloromethane, dimethylformamide, methanol, ethanol and glycol; the mass concentration of the water-soluble polymer in the polar organic solvent is 1-10 mg/mL, and the heating and stirring are specifically stirring at the rotating speed of 300-1000 rpm/min at 60 ℃; the water-soluble polymer and PEDOT: the mass ratio of the PSS is 0-0.83: 1.

further, in the step (2): the substrate is a flexible substrate or a rigid substrate, the flexible substrate is one of polyethylene terephthalate (PET), Polyimide (PI) or Polydimethylsiloxane (PDMS), and the rigid substrate is one of a glass sheet, a silicon wafer and a quartz sheet; the spin coating specifically comprises the following steps: spin coating at 800-80000 rpm/min for 30-60 s; the blade coating specifically comprises the following steps: the distance between the scraper and the substrate is 0.1-1.2 mm, and the scraping speed of the scraper is 0.05-5 cm/s; the silk-screen printing specifically comprises the following steps: a 100-600 mesh screen is used.

Further, in the step (3): the annealing and drying temperature is 25-200 ℃, and the time is 1-3 h; the ultrasonic power is 10-100W, and the ultrasonic time is 20-60 s.

Further, the fully flexible transparent film electrode obtained in the step (3) is placed in strong acid (concentrated sulfuric acid), medium strong acid (methanesulfonic acid) or organic solvent (methanol) for post-treatment so as to strengthen the conductivity of the fully flexible transparent film electrode.

In the third technical scheme of the invention, the fully flexible transparent film electrode is applied to the preparation of flexible electronic devices, optoelectronic devices or electronic devices.

In the fourth technical scheme of the invention, the flexible electronic device comprises the fully flexible transparent film electrode; the flexible electronic device is a flexible wearable sensor, a flexible light emitting diode or a flexible supercapacitor.

In the fifth technical scheme of the invention, the preparation method of the flexible electronic device comprises the following steps when the flexible electronic device is a flexible wearable sensor:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a PEDOT (PSS) solution to obtain a fully flexible transparent film solution;

(2) spin-coating the fully flexible transparent film solution on one surface of PDMS subjected to oxygen plasma treatment, and annealing and drying;

(3) and (3) repeating the step (2) to prepare a fully flexible transparent film on the other surface of the PDMS subjected to the oxygen plasma treatment to obtain the flexible wearable sensor.

In the sixth technical scheme of the invention, the preparation method of the flexible electronic device comprises the following steps when the flexible electronic device is a flexible light emitting diode:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a PEDOT (PSS) solution to obtain a fully flexible transparent film solution;

(2) spin-coating the fully flexible transparent film solution on the PET substrate subjected to ultraviolet treatment, and annealing and drying to obtain a fully flexible transparent film electrode;

(3) putting the fully flexible transparent film electrode into an evaporation device, and carrying out evaporation in sequence according to the sequence of N, N '-di (1-naphthyl) -N, N' -diphenyl- (1,1 '-biphenyl) -4,4' -diamine (NPB) (60 nm)/tris (8-hydroxyquinoline) aluminum (Alq3) (60 nm)/lithium fluoride (1 nm)/aluminum (80nm) and the film thickness to obtain the flexible light-emitting diode.

Seventh of the technical scheme of the present invention, in the preparation method of the flexible electronic device, when the flexible electronic device is a flexible supercapacitor, the method comprises the following steps:

(1) dissolving a water-soluble polymer in a polar organic solvent, heating and stirring the solution, and uniformly stirring the solution and a PEDOT (PSS) solution to obtain a fully flexible transparent film solution;

(2) spin-coating the fully flexible transparent film solution on the PDMS subjected to ultraviolet treatment, and annealing and drying to obtain a fully flexible transparent film electrode;

(3) and assembling the fully flexible transparent film electrode and the hydrogel electrolyte to obtain the flexible supercapacitor.

Further, the polar organic solvent in the step (1) is one or more of acetonitrile, acetone, dichloromethane, dimethylformamide, methanol, ethanol and ethylene glycol; the mass concentration of the water-soluble polymer in the polar organic solvent is 1-10 mg/mL, and the heating and stirring are specifically stirring at the rotating speed of 300-1000 rpm/min at 60 ℃; the water-soluble polymer and PEDOT: the mass ratio of the PSS is 0-0.83: 1, excluding 0;

the spin coating in the step (2) is carried out at the speed of 2000r/min, and the annealing and drying are specifically carried out at the temperature of 110 ℃ for 10 min.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention adopts the water-soluble polymer as the dopant, and can realize the preparation of the high-transparency full-flexible thin film electrode by utilizing solution processing modes such as spin coating, blade coating, screen printing and the like. Meanwhile, the addition of the water-soluble polymer can also effectively shield the interaction of coulomb force between PEDOT and PSS, so that the PEDOT and the PSS are promoted to be separated, and the conformation of a PEDOT chain is changed, thereby improving the conductivity and the mechanical property of the film electrode and meeting the requirements of a flexible electronic device on the electrode;

(2) the prepared fully-flexible transparent film electrode has good mechanical property, can realize self-supporting, and can be transferred to any device surface with a complex shape to be used as an electrode. And since it is detached from the substrate, it can be post-treated by soaking it alone in strong acid (concentrated sulfuric acid), medium strong acid (methanesulfonic acid) or organic solvent (methanol) to further improve the conductive properties of the electrode, by PEDOT: the conductivity of the PSS film can be improved to 3204S/cm.

(3) When the fully flexible transparent film electrode prepared by the invention is respectively applied to flexible electronic devices such as ultrathin flexible wearable sensors with shape-preserving capability, flexible light-emitting diodes and flexible super capacitors, the flexible electronic devices can work well and show good properties. The results show that the all-polymer-based flexible transparent conductive electrode prepared by the invention can be used as a universal electrode for replacing ITO (indium tin oxide) to be applied to flexible electronic devices, and has a good application prospect in the future.

Drawings

FIG. 1 is a schematic diagram of a process of preparing a fully flexible transparent thin film electrode by a spin coating method in example 1 of the present invention;

FIG. 2 is a diagram of a transferable implementation of a fully flexible transparent thin-film electrode according to example 1 of the present invention;

fig. 3 shows the effect of different contents of PEO (Mn 5000000) on the conductivity of a fully flexible transparent thin film electrode in example 1 of the present invention;

FIG. 4 is a schematic representation of the conductivity enhancement of PEO to PEDOT/PSS in example 1 of the present invention;

FIG. 5 is an AFM phase diagram representation of the effect of PEO doping on the morphology of PEDOT/PSS films in example 1 of the present invention;

fig. 6 shows the effect of different contents of PEO (Mn 5000000) on transparency of a fully flexible transparent thin film electrode in example 1 of the present invention;

fig. 7 shows the effect of different contents of PEO (Mn 5000000) on the mechanical properties of fully flexible transparent thin film electrodes in example 1 of the present invention;

fig. 8 shows the effect of different contents of PEO (Mn ═ 2500) on conductivity and light transmission of fully flexible transparent thin film electrodes in example 2 of the present invention;

fig. 9 shows the effect of different contents of PEO (Mn 1000000) on the conductivity and transmittance of the fully flexible transparent thin film electrode in example 2 of the present invention;

fig. 10 shows the effect of different contents of PEO (Mn ═ 8000000) on conductivity and light transmission of fully flexible transparent thin film electrodes in example 2 of the present invention;

fig. 11 is a schematic structural diagram and a graph of a strain response test result of a flexible wearable sensor in embodiment 3 of the present invention, where fig. a is a schematic structural diagram of a principle of the flexible wearable sensor, fig. b is a test for monitoring a quick bending response of a finger, fig. c is a test for monitoring a quick pressing response of a finger, and fig. d is a test for monitoring responses of fingers at different bending angles;

fig. 12 is a schematic structural diagram of a flexible light emitting diode, and graphs of a test result of light emitting performance and electrical performance in example 4 of the present invention, where graph a is a schematic structural diagram of the flexible light emitting diode, graph b is a graph of a test result of voltage-luminance of the light emitting diode, graph c is a graph of a test result of voltage-current density of the light emitting diode, and graph d is a graph of a test result of voltage-current efficiency of the light emitting diode;

fig. 13 is a schematic structural diagram and a test result graph of electrochemical properties of the flexible supercapacitor in example 5 of the present invention, where fig. a is a schematic structural diagram of the flexible supercapacitor, fig. b is a test result graph of Cyclic Voltammetry (CV) of the supercapacitor, fig. c is a test result graph of constant current charging and discharging (GCD) of the supercapacitor, and fig. d is a calculated result graph of mass-to-capacitance at different scanning speeds;

fig. 14 is a diagram of an object of a flexible color-changeable supercapacitor in embodiment 5 of the present invention.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

Example 1

(1) Poly (ethylene oxide) (PEO) solid powder was dissolved in N, N-Dimethylformamide (DMF) solution and stirred at 60 ℃ at 500rpm/min until a uniform and transparent solution A was obtained. The molecular weight of the PEO was 5000000.

(2) PH1000 is selected as a PEDOT-PSS solution, wherein the solid content of PEDOT is 1.3%, and the mass ratio of PEDOT to PSS is 1: 6. Before use, the solution was filtered through a 0.45 μm water-based glass fiber frit to remove large particles from the solution.

(3) And (3) mixing the solution A obtained in the step (1) and the PEDOT-PSS solution obtained in the step (2) to ensure that the doping amount of PEO is 3 wt%, 13 wt%, 23 wt%, 33 wt%, 43 wt% and 53 wt%, and stirring at the rotating speed of 1000rpm/min for 2-4 hours until a uniformly mixed solution B is obtained.

(4) And (3) transferring 200 mu L of the mixed solution B obtained in the step (3) to a substrate of the ultraviolet-treated glass sheet by using a liquid transfer gun, spin-coating at the speed of 3000rpm/min for 40s, annealing and drying at the temperature of 110 ℃ for 10 minutes, immediately transferring to a glass container containing water, and performing 50W ultrasonic treatment for 30s to obtain the fully flexible transparent film electrode.

(5) And (3) soaking the prepared fully-flexible transparent film electrode in a sulfuric acid solution with the volume fraction of 30% for 10min, and performing acid treatment to obtain the fully-flexible transparent film electrode subjected to acid treatment.

The specific preparation process is shown in figure 1; the transfer test was performed on the prepared fully flexible transparent thin film electrode, and the result is shown in fig. 2.

(6) The conductivity test of the prepared fully flexible transparent thin film electrode and the acid-treated fully flexible transparent thin film electrode was verified, and the results are shown in fig. 3. The principle of the conductivity enhancement of PEO to PEDOT: PSS is schematically shown in FIG. 4.

(7) The preparation of the fully flexible transparent thin film electrode of the step (4) was directly performed by mixing the PEDOT-PSS solution obtained in the step (2), and the obtained product was subjected to AFM analysis with the fully flexible transparent thin film electrode of the step (4) having a PEO doping amount of 33 wt%, and the result is shown in fig. 5.

(8) The prepared fully flexible transparent film electrode (before acid treatment) was subjected to light transmittance test verification, and the result is shown in fig. 6.

(9) The mechanical property test verification is carried out on the prepared fully flexible transparent film electrode (before acid treatment), and the result is shown in figure 7.

Example 2

The difference from example 1 is that the molecular weights of PEO in step (1) were 2500, 1000000, 8000000, respectively.

The conductivity and light transmittance of the prepared fully flexible transparent film electrode (before acid treatment) were verified, and the results are shown in fig. 8-10.

Example 3 preparation of Flexible wearable Sensors

(1) Dissolving poly (ethylene oxide) (PEO) solid powder in N, N-Dimethylformamide (DMF) solution, and stirring at the rotating speed of 300-500 rpm/min at 60 ℃ until uniform and transparent solution A is obtained. The molecular weight of the PEO was 5000000.

(2) Mixing a certain amount of the solution A in the step (1) with a PEDOT/PSS solution (the PEO doping amount is 33 wt%), stirring at the rotating speed of 1000rpm/min for 4 hours until a uniformly mixed solution B is obtained;

(3) obtaining an ultrathin PDMS film: mixing a PDMS prepolymer (Sylgard 184, Dow Corning) and a PDMS curing agent in a weight ratio of 10: 1, mixing.

(4) The step (3) mixture was degassed in vacuo for 30 minutes to eliminate air and form PDMS prepolymer. The prepolymer was poured onto a 3X 3cm silicon wafer hydrophobicized with Octadecyltrimethoxysilane (OTMS), spun at 1500rpm for 1 minute and finally cured at a temperature of 75 ℃ for 1 hour.

(5) And (3) using a pipetting gun to pipette the mixed solution B in the step (2) to one side of the PDMS film which is treated by the oxygen plasma, spin-coating the PDMS film at the speed of 2000rpm for 30 seconds, then annealing the PDMS film at the temperature of 110 ℃ for 10 minutes, and preparing the other side of the PDMS film by the same method, thus obtaining the ultrathin transparent flexible wearable sensor.

The sensor was tested by coating both sides of the pressure sensor with silver paste, drying, and connecting the test instrument and the silver paste-coated portion with copper wires. The specific result is shown in fig. 11, wherein a is a schematic diagram of a principle structure of the flexible wearable sensor, b is a test for monitoring the quick bending response of the finger, c is a test for monitoring the quick pressing response of the finger, and d is a test for monitoring the responses of the finger at different bending angles. The result shows that the sensor can identify different states of finger bending and finger pressing and has different responses, can also identify different angles of finger bending, and has high sensitivity and stability.

EXAMPLE 4 preparation of Flexible light emitting diodes

(1) Poly (ethylene oxide) (PEO) solid powder was dissolved in N, N-Dimethylformamide (DMF) solution and stirred at 60 ℃ at 500rpm/min until a uniform and transparent solution A was obtained. The molecular weight of the PEO was 5000000.

(2) Mixing a certain amount of the solution A in the step (1) with a PEDOT/PSS solution (the PEO doping amount is 33 wt%), stirring at the rotating speed of 1000rpm/min for 4 hours until a uniformly mixed solution B is obtained;

(3) and (3) spin-coating the mixed solution B in the step (2) on 3 × 3cm PET subjected to ultraviolet treatment at 2000rpm/min, and annealing at 110 ℃ for 10 minutes to obtain the fully flexible transparent thin film electrode on the substrate.

(4) The thin film electrode was placed in an evaporation apparatus, and N, N '-bis (1-naphthyl) -N, N' -diphenyl- (1,1 '-biphenyl) -4,4' -diamine (NPB) (60 nm)/tris (8-hydroxyquinoline) aluminum (Alq3) (60 nm)/lithium fluoride (1 nm)/aluminum (80nm) were sequentially evaporated in this order and film thickness, respectively, where an all-polymer-based flexible transparent conductive electrode served as an anode, NPB served as a hole transport layer, Alq3 served as both a host material and an electron transport material, and lithium fluoride and aluminum served as an electron injection material and a cathode material.

(5) Respectively carrying out evaporation deposition according to the evaporation sequence in the step (4) to obtain a flexible light emitting diode, and further carrying out a light emitting test on the light emitting diode, wherein the result is shown in fig. 12, wherein a is a schematic diagram of a principle structure of the flexible light emitting diodeFig. b is a led voltage-luminance test, fig. c is a led voltage-current density test, and fig. d is a led voltage-current efficiency test. The highest luminous brightness of the device can reach 696cd m^-2The minimum starting voltage is 3.9V, and the maximum current efficiency is 3.5cd A^-1。

Example 5 preparation of Flexible supercapacitor

(1) Mixing 3.17X 10^-5g of the surfactant Sodium Dodecyl Sulfate (SDS),0.164g of the amphiphilic molecule Dodecyl Glyceryl Itaconate (DGI),0.569g of the polymerizable monomer acrylamide (AAM) and 6.17X 10^-4Dispersing a crosslinking agent N, N' -Methylene Bisacrylamide (MBAA) in 4mL of deionized water, and stirring at the rotating speed of 500rpm/min at 50 ℃ until a uniform and transparent mixed solution is obtained;

(2) adding 0.0018g of 2-hydroxy-4' - (2-hydroxyethoxy) -2-methyl propiophenone serving as a photoinitiator into the mixed solution in the step (1), stirring at the rotating speed of 500rpm/min for 5min at 50 ℃ in a dark condition, and then performing phase formation in a water bath at 55 ℃ for 24 hours until a uniform and transparent light blue solution is obtained;

(3) injecting the light blue mixed solution in the step (2) into a glass mold with the interval of 1000 mu m, and carrying out photopolymerization for 6 hours in an ultraviolet crosslinking instrument at the temperature of 55 ℃ to obtain hydrogel;

(4) the hydrogel obtained is firstly hydrolyzed in aqueous solution for 100 hours to obtain the hydrogel with rapid color change.

(5) Swelling the hydrogel obtained in the step (4) in a 1M phosphoric acid solution for 24 hours until the hydrogel is balanced to obtain a colored hydrogel electrolyte film;

(6) poly (ethylene oxide) (PEO) solid powder was dissolved in N, N-Dimethylformamide (DMF) solution and stirred at 60 ℃ at 500rpm/min until a uniform and transparent solution A was obtained. The molecular weight of the PEO was 5000000.

(7) Mixing the solution A with the PEDOT/PSS solution (the PEO doping amount is 33 wt%) in a certain amount in the step (6), and stirring at the rotating speed of 1000rpm/min for 4 hours until a uniformly mixed solution B is obtained;

(8) and (3) spin-coating the mixed solution B in the step (7) on 3 × 3cm PDMS subjected to ultraviolet treatment at 2000rpm/min, and annealing at 110 ℃ for 10 minutes to obtain a fully flexible transparent thin film electrode on the substrate.

(9) And (3) assembling the colored hydrogel electrolyte film in the step (5) and the full polymer-based flexible transparent conductive electrode in the step (7) to prepare the flexible color-variable supercapacitor, wherein the specific structure is shown in fig. 13, the diagram a is a schematic diagram of a principle structure of the flexible supercapacitor, the diagram b is a Cyclic Voltammetry (CV) test of the supercapacitor, the diagram c is a constant current charging and discharging (GCD) test of the supercapacitor, and the diagram d is a mass-to-capacitance calculation under different scanning speeds. The product object diagram is shown in FIG. 14. The electrochemical properties (cyclic voltammetry and galvanostatic charging and discharging) of this capacitor were then tested and the results are shown in FIG. 13, the maximum specific capacitance of this supercapacitor being at 10mV s^-1At time 28F g^-1And even at 400mV s^-1Still maintains 18F g at high scan rates^-1The specific capacitance of (c).

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included therein.