Modularized integrated stretchable electrochromic device array and preparation method thereof

Abstract

The invention discloses a modular integrated stretchable electrochromic device array and a preparation method thereof. The modular integrated stretchable electrochromic device array comprises a hydrogel-based adhesion substrate, ionic conductive hydrogel, electrochromic units, a microcontroller and hydrogel-based conductive electrodes. The invention discloses acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerin hydrogel with a substrate having excellent adhesion, stretchability and transparency. The ionic conductive hydrogel has excellent ionic conductivity, stretchability and transparency, and the electrochromic layer is dispensed on the surface of the hydrogel to form a uniform composite layer, so that the electrode has excellent electronic conductivity, stretchability and transparency. According to the flexible stretchable electrochromic array, simple, convenient and rapid integration of devices can be achieved by means of the self-adhesion performance between hydrogel and modular structural design, and the devices can still run reliably after multiple times of stretching circulation and show excellent stability; the response speed is excellent, the optical contrast ratio is good, and the visual response to voltage is realized.

Description

Technical Field

[0001] The present invention relates to the field of preparation of electrochromic devices, and particularly to a modular integrated stretchable electrochromic device array and a preparation method thereof. Background Art

[0002] The rapid development of the Internet of Things and flexible electronics technologies has promoted the rise of user-centered flexible visual sensing technologies, which can be widely applied to human-computer interaction and intelligent sensing. Flexible visual sensing devices can convert mechanical, optoelectronic, physiological, and electrochemical signals into changes in color or brightness, enabling real-time and direct monitoring of external signals invisible to the naked eye, and providing innovative solutions for health monitoring, medical diagnosis, food safety, environmental detection, and energy management. However, most current flexible visual sensing devices mainly rely on single brightness or color depth changes to transmit information, which is vulnerable to environmental interference, thus affecting the reliability of monitoring. Flexible visual sensing systems adopting colorful and multimodal sensing fusion can effectively avoid these limitations, but also increase the complexity of material and device design.

[0003] Through systematic integration of visual sensing, soft electronics, and functional / nanomaterials, rapid response and direct visual display of monitored analytes can already be achieved. In addition, advanced integration technologies have also promoted the development of multimodal or multifunctional integrated flexible visual sensing systems, enabling more complex and precise monitoring and preliminary intelligent decision-making. The latest integrated flexible visual sensing technologies are developing towards higher stability, better stretchability, and more flexible autonomy. The progress of these technologies endows visual sensing devices with more operability and adaptability, enabling them to perform more precise, complex, and challenging monitoring tasks under complex shapes and dynamic systems. However, during the device integration process, precise circuit layout and meticulous structure assembly are required, which usually rely on advanced manufacturing technologies such as printed circuit board technology, 3D printing, laser engraving, and magnetron sputtering, etc. These devices are costly and require professional operation skills, seriously affecting the transformation of devices towards large-scale and batch production. In addition, currently, the devices are limited by flexible substrates (including polydimethylsiloxane, styrene-ethylene-butylene-styrene block copolymer, and polyethylene terephthalate), and can only achieve a certain range of bending, deformation, and ≤20% stretching, hindering close fitting under dynamic changes or complex environments (non-planar or irregular surfaces), and reducing the adaptability, functionality, and comfort of the devices. At the same time, current multifunctional or multimodal integrated visual sensing devices usually involve the integration of multiple sensing elements. These devices often can only respond to limited sensing elements, and this limitation significantly narrows their potential application scope. Summary of the Invention

[0004] The object of the present invention is to solve the technical problems that existing flexible integrated vision sensor devices need to rely on complex flexible circuit layout and precise structural assembly to achieve precise monitoring, tensile and bending stability, and single functionality. Therefore, a flexible and stretchable modular electrochromic device and a preparation method thereof are provided. In the present invention, the flexible and stretchable modular electrochromic device can be closely integrated through the self-adhesion between hydrogels with excellent mechanical and functional properties, thereby ensuring the tensile stability and simplicity and flexibility of the device. And the device has excellent tensile properties (cyclic tensile 8000 times with a tensile elongation rate of 80%), fast response speed (tb = 2s, tc = 2s), and optical contrast (DT = 43%).

[0005] The present invention adopts the following technical solutions: A modular integrated stretchable electrochromic device array, comprising a hydrogel-based flexible adhesion substrate, an electrochromic unit, a microcontroller, and a hydrogel-based conductive electrode arranged in sequence.

[0006] A matrix for a modular integrated stretchable electrochromic device array, comprising a hydrogel-based flexible adhesion substrate, a modular electrochromic unit, and a hydrogel-based conductive electrode arranged in sequence.

[0007] In the present invention, the hydrogel-based flexible adhesion substrate is an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate; the electrochromic unit includes an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel and a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid electrochromic layer on its surface; the hydrogel-based conductive electrode is a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid conductive hydrogel.

[0008] In the present invention, the number of electrochromic units is not greater than the number of microcontroller ports. The microcontroller is a prior art and can be commercially purchased or obtained according to conventional methods. As common knowledge, the microcontroller has ports, power interfaces, sensor interfaces, etc. In the present invention, the number of electrochromic units is not greater than the number of microcontroller ports, that is, the number of electrochromic units is less than the number of microcontroller ports or the number of electrochromic units is the same as the number of microcontroller ports; a plurality of electrochromic units form an array, and the specific arrangement of the array does not affect the understanding of those skilled in the art of the technical effects of the present invention.

[0009] The present invention discloses a preparation method of the above modular integrated stretchable electrochromic device array, comprising the following steps: assembling the hydrogel-based adhesion substrate, the electrochromic unit, the microcontroller, and the hydrogel-based conductive electrode in sequence by a layer-by-layer assembly method to obtain a modular integrated stretchable electrochromic device array.

[0010] In the present invention, acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate is prepared from acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and glycerol; acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel is prepared from acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and lithium chloride. Tungsten oxide quantum dots are mixed with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution and surfactant to prepare tungsten oxide quantum dots / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution. The tungsten oxide quantum dots / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution is coated on the surface of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel to form an electrochromic unit; polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared from polyvinyl alcohol, acrylic acid, glycerol, and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution.

[0011] In the present invention, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, glycerol, initiator, N,N'-methylenebisacrylamide, surfactant, and water are mixed to form a solution, and then dried to obtain an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate; acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, lithium chloride, initiator, N,N'-methylenebisacrylamide, surfactant, and water are mixed to form a solution, and then dried to obtain acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel; hydrochloric acid solution is added dropwise to an aqueous solution of sodium tungstate dihydrate until precipitation occurs, and then the precipitate is taken and added to ethylene glycol to form a transparent solution, and heated to react to obtain a tungsten oxide quantum dot solution; the tungsten oxide quantum dot solution, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution, ethylene glycol, and surfactant are mixed to prepare a tungsten oxide quantum dots / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution; polyvinyl alcohol, acrylic acid, glycerol, and water are mixed to form a solution, and then subjected to freeze-thaw cycles to obtain polyvinyl alcohol / acrylic acid / glycerol hydrogel, and then a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid film is formed on the surface of the polyvinyl alcohol / acrylic acid / glycerol hydrogel by spin coating, and after annealing treatment, polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared.

[0012] The present invention discloses the application of the above modularly integrated stretchable electrochromic device array or the matrix for the modularly integrated stretchable electrochromic device array in the preparation of electronic devices.

[0013] The present invention discloses the application of the above-mentioned modular integrated stretchable electrochromic device array in the preparation of flexible modular color-changing devices or as a flexible modular color-changing device.

[0014] The present invention discloses the application of the above-mentioned modular integrated stretchable electrochromic device array in the preparation of health monitoring and medical diagnostic devices.

[0015] Specifically, the present invention discloses a modular integrated stretchable electrochromic device array and a preparation method thereof, comprising the following steps: (1) Using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and glycerol as raw materials, prepare an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate; (2) Using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and lithium chloride as raw materials, prepare an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel; (3) Using ethylene glycol, sodium tungstate dihydrate, and hydrochloric acid solution as raw materials, prepare a tungsten oxide quantum dot solution; (4) Using polyvinyl alcohol, acrylic acid, glycerol, and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution as raw materials, prepare a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel by freeze cycling. Finally, a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid film is formed on the surface of the polyvinyl alcohol / acrylic acid / glycerol hydrogel by spin coating, and a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared after annealing treatment; (5) Mix tungsten oxide quantum dots with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution and a surfactant to prepare a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution; (6) Using polyethylene terephthalate (PET) as a template material, having one or a plurality of pores; (7) Attach (place) the template on the surface of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel, and dropwise coat the tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution into the pores by drop coating. After annealing treatment, one or a plurality of electrochromic units are formed on the surface of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel; (8) The hydrogel-based adhesion substrate, one or a plurality of electrochromic units, a microcontroller, and a hydrogel-based conductive electrode are assembled successively in a layer-by-layer assembly manner, and a flexible and stretchable electrochromic device is prepared by utilizing the adhesion performance between hydrogels. The specific assembly method is a conventional technique, and each layer can be simply pasted together without the need for additional adhesives or adhesive layers.

[0016] In the present invention, in step (1), acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, glycerol, ammonium persulfate, N,N'-methylenebisacrylamide, polyvinylpyrrolidone, and water are mixed to form a homogeneous solution, and then dried to obtain an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate. Preferably, the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, glycerol, ammonium persulfate, N,N'-methylenebisacrylamide, polyvinylpyrrolidone, and water is (15-25):(15-25):(20-40):(0.15-0.2):(0.1-0.15):(1.5-2):100.

[0017] In the present invention, in step (2), acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, lithium chloride, ammonium persulfate, N,N'-methylenebisacrylamide, polyvinylpyrrolidone, and water are mixed and stirred, and then dried to obtain an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel. Preferably, the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, lithium chloride, ammonium persulfate, N,N'-methylenebisacrylamide, polyvinylpyrrolidone, and water is (20-30):(5-7):(10-20):(0.15-0.2):(0.1-0.15):(1.5-2):100.

[0018] In the present invention, in step (3), sodium tungstate dihydrate is stirred and dissolved in water, and then hydrochloric acid solution is added dropwise until precipitation is complete. The supernatant solution is removed by centrifugation and washed repeatedly until the pH of the precipitate is ≥3. The centrifugation process is as follows: the centrifugation speed is 8000-12000 r / min, the centrifugation time is 8-12 min, and ethylene glycol is added and heated to dissolve to form a transparent solution. It is transferred to a reaction kettle, heated at a constant temperature in an oven and then cooled to room temperature. The temperature of the hydrothermal reaction is 170-190 °C, and the time of the hydrothermal reaction is 40-55 h. The obtained solution is taken out and subjected to dialysis treatment to prepare a tungsten oxide quantum dot solution. The dialysis time is 12-36 h, and deionized water is replaced every 4 h. Preferably, the mass ratio of sodium tungstate dihydrate to water is (0.8-0.9):1; the mass ratio of the precipitate to ethylene glycol is 1:(4-6), the temperature of the hydrothermal reaction is 180 °C, the time of the hydrothermal reaction is 48 h, the centrifugation speed is 10000 r / min, the centrifugation time is 10 min, and the dialysis time is 24 h.

[0019] In the present invention, in step (4), polyvinyl alcohol, acrylic acid, glycerol and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution are used as raw materials, and a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared through freeze-thaw cycles. Finally, a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid film is formed on the surface of the polyvinyl alcohol / acrylic acid / glycerol hydrogel by spin coating at a spin coating speed of 1000 - 3000 r / min and a spin coating time of 50 - 70 s. After annealing treatment at 80 °C for 3 - 7 min, a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared; preferably, the mass ratio of polyvinyl alcohol, acrylic acid, glycerol and water is (18 - 22):(22 - 26):(46 - 50):100. Freezing process: the freezing temperature is -16 to -20 °C, the freezing time is 3 - 5 h, the thawing time is 2 - 4 h, and the freeze-thaw cycles are 3 - 4 times. Spin coating process: the spin coating speed is 2000 r / min, the spin coating time is 60 s. The annealing time is 5 min.

[0020] In the present invention, in step (5), tungsten oxide quantum dots are mixed with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution and a surfactant to prepare a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution. The mass ratio of tungsten oxide quantum dots to poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution is 2:(0.8 - 1.2); the mass ratio of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution: ethylene glycol: surfactant is 1:(0.12 - 0.16):(0.0002 - 0.0003). Preferably, the mass ratio of tungsten oxide quantum dots to poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution is 2:1; the mass ratio of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution: ethylene glycol: surfactant is 1:0.14:0.0025 The present invention discloses the application of the above-mentioned modular integrated stretchable electrochromic device array and its preparation method in the preparation of flexible modular color-changing devices or as flexible modular color-changing devices. Further, the present invention discloses the application of the above-mentioned flexible stretchable modular electrochromic device in the preparation of health monitoring and medical diagnosis.

[0021] The present invention relates to a modular integrated stretchable electrochromic device array and a preparation method thereof, which includes an acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate, a modular tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid-acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / lithium chloride electrochromic unit, a microcontroller, and a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel-based conductive electrode. In the present invention, the modular integrated stretchable electrochromic device array and the preparation method thereof can rely on the self-adhesion performance between hydrogels and the modular structure design to achieve the simple and rapid integration of the device, and prepare a flexible stretchable modular electrochromic device.

[0022] The thickness of the acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate of the present invention is 0.5 - 1.5 mm; the thickness of the modular tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid-acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / lithium chloride electrochromic unit is 0.5 - 1.5 mm; the thickness of the microcontroller is 0.3 - 0.7 mm; and the thickness of the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel-based conductive electrode is 0.5 - 1.5 mm. Preferably, the thickness of the acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate is 1 mm; the thickness of the modular tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid-acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / lithium chloride electrochromic unit is 1 mm; the thickness of the microcontroller is 0.5 mm; and the thickness of the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel-based conductive electrode is 1 mm.

[0023] Advantages of the present invention: (1) Through the modular structure design and the self-adhesion performance between hydrogels, the present invention avoids the design of high-density and high-precision flexible circuits for integrated devices, saves the manufacturing cost and operation precision of the devices, realizes the preparation of simple, flexible and rapid flexible integrated devices, and provides a feasibility for large-scale and batch production.

[0024] (2) The stretchable integrated electrochromic device prepared by the present invention uses hydrogel as the main material, solves the problem that the existing flexible electrochromic devices can only achieve bending, deformation within a certain range and stretching of ≤20%, realizes the preparation of an integrated visual sensor device with high electrochromic performance and high stretchability, and improves the adhesion performance of the device in dynamic environmental changes or complex environments. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0026] Figure 1 It is a preparation flow chart of a flexible modular electrochromic device.

[0027] Figure 2 It is a polyethylene terephthalate template prepared by a laser cutting machine.

[0028] Figure 3 It is a structural schematic diagram of a 6-port microcontroller.

[0029] Figure 4 It is a structural schematic diagram of a stretchable modular electrochromic device.

[0030] Figure 5 It is an operation flow chart of a stretchable modular electrochromic device.

[0031] Figure 6 It is a transmittance curve, shear strength, hydrogel air permeability characterization, and air permeability comparison chart of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based adhesion substrate with other commercial materials.

[0032] Figure 7 It is the conductivity, transmittance curve, ionic conductivity, and mechanical tensile properties of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride ion-conductive hydrogel.

[0033] Figure 8 It is the resistance comparison of polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel with other hydrogels, the resistance and transmittance changes at different spin coating speeds, the resistance changes after standing at room temperature for different times, and the resistance changes after stretching cycles at 100% tensile elongation.

[0034] Figure 9 It is an optical photograph of the bending and twisting of a stretchable modular electrochromic device.

[0035] Figure 10 It is an optical photograph before and after stretching and the electrochromic behavior after stretching of a stretchable modular electrochromic device when the tensile elongation is 80%.

[0036] Figure 11 It is an optical photograph, optical contrast, and response time curve of the color change behavior of a stretchable modular electrochromic unit.

[0037] Figure 12 It is the response behavior of a stretchable modular electrochromic device to different voltages. Detailed implementation mode

[0038] In the prior art, during the device integration process, high-density and high-precision flexible circuit preparation is required by means of etching, deposition, printing, etc. Tiny errors may lead to the failure of the overall circuit. At the same time, during high-frequency bending and stretching, the circuit is prone to breakage, resulting in the device being unable to work properly. The present invention starts from aspects such as materials engineering and structural design, replaces the traditional flexible circuit with a stretchable modular hydrogel electrochromic unit, and realizes the preparation of a highly stretchable and simple and fast integrated flexible electrochromic device through the self-adhesion between hydrogels.

[0039] As an example, the present invention discloses a modular integrated stretchable electrochromic device array and a preparation method thereof, including the following steps: (1) Using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and glycerol as raw materials, prepare an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate; (2) Using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and lithium chloride as raw materials, prepare an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel; (3) Using ethylene glycol, sodium tungstate dihydrate, and hydrochloric acid solution as raw materials, prepare a tungsten oxide quantum dot solution; (4) Using polyvinyl alcohol, acrylic acid, glycerol, and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution as raw materials, prepare a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel; (5) Mix tungsten oxide quantum dots with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution and a surfactant to prepare a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution; (6) Using polyethylene terephthalate (PET) as a template material, prepare holes by laser cutting; (7) Attach the perforated template to the surface of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel, and dropwise coat the tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution into the holes. After annealing treatment, form an electrochromic unit on the surface of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel; (8) Divide the prepared electrochromic acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel into electrochromic units; (9) Take a microcontroller with an open circuit port; (10)Assemble the hydrogel-based adhesion substrate, modular electrochromic unit, microcontroller, and hydrogel-based conductive electrode in a layer-by-layer manner to prepare a flexible and stretchable electrochromic device by utilizing the adhesion properties between hydrogels. Figure 1 It is the preparation flow chart of the above flexible modular electrochromic device.

[0040] In the above step (1), acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, glycerol, ammonium persulfate, N,N'-methylenebisacrylamide, polyvinylpyrrolidone, and water are mixed to form a homogeneous solution, and then dried to obtain an acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based flexible adhesion substrate.

[0041] In the above step (2), acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, lithium chloride, ammonium persulfate, N,N'-methylenebisacrylamide, polyvinylpyrrolidone, and water are mixed and stirred, and then dried to obtain an acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / lithium chloride hydrogel.

[0042] In the above step (3), sodium tungstate dihydrate is stirred and dissolved in water, and then hydrochloric acid solution is added dropwise until precipitation is complete. The supernatant solution is removed by centrifugation and washed repeatedly until the pH of the precipitate is ≥3, and ethylene glycol is added and heated to dissolve to form a transparent solution. It is transferred to a reaction kettle, heated at a constant temperature in an oven and then cooled to room temperature, and the obtained solution is dialyzed to prepare a tungsten oxide quantum dot solution.

[0043] In the above step (4), polyvinyl alcohol, acrylic acid, glycerol, and water are mixed to form a homogeneous solution, and then frozen cycled to obtain a polyvinyl alcohol / acrylic acid / glycerol hydrogel. Finally, a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid film is formed on the surface of the polyvinyl alcohol / acrylic acid / glycerol hydrogel by spin coating, and after annealing treatment, a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared.

[0044] In the above step (5), the tungsten oxide quantum dot solution, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution, ethylene glycol, and surfactant are mixed and stirred vigorously to prepare a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution.

[0045] The above centrifugation process is as follows: the centrifugation speed is 8000 - 12000 r / min, the centrifugation time is 8 - 12 min, the dialysis time is 12 - 36 h, and the water is changed every 4 h.

[0046] The above spin coating process is as follows: the spin coating speed is 1000 - 3000 r / min, and the spin coating time is 50 - 70 s.

[0047] The mass ratio of the above-mentioned tungsten oxide quantum dots to poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution is 2:(0.8 - 1.2); the mass ratio of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution: ethylene glycol: surfactant is 1:(0.05 - 0.1):(0.0002 - 0.0003).

[0048] In the above step (3), a tungsten oxide quantum dot solution is prepared by a one-step hydrothermal method. The temperature of the hydrothermal reaction is 170 - 190 °C, and the time of the hydrothermal reaction is 40 - 55 h.

[0049] The present invention discloses a flexible stretchable modular electrochromic device prepared by the above modular integrated stretchable electrochromic device array and its preparation method, and the application of the device in the preparation of flexible modular color-changing devices or as a flexible modular color-changing device; further, its application in the preparation of health monitoring and medical diagnosis.

[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. In the description of the present invention, the mention of "embodiment", "one embodiment" or "other embodiments" means that the specific features, structures or characteristics described in conjunction with the embodiments are included in at least some embodiments, but not necessarily all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. The raw materials used in the present invention are existing products, and the specific preparation operations and performance tests are conventional technologies.

[0051] As Figure 4 shown, the present invention adopts a modular structure design. By constructing a multi-layer composite structure, an integrated stretchable modular electrochromic device is prepared, which shows broad application prospects in the fields of wearable devices, health monitoring and visual medical diagnosis.

[0052] The raw materials and molds used in the present invention are existing products, and the specific preparation operations and performance tests are conventional technologies. Among them, the poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution is the PH1000 type reagent produced by Heraeus Electronic Materials Company. Mechanical property test: The tensile property test of the device is carried out by using a Mark-10 seriesf mesur type mechanical testing machine. Sheet resistance test of the conductive electrode: The sheet resistance of the conductive electrode is tested by using an ST-2258C digital four-probe. Transmittance and optical contrast test: The transmittance of the conductive electrode and the electrochromic layer and the transmittance difference of the device in the colored and faded states at a wavelength of 550 nm are measured by using an ultraviolet spectrophotometer. Preparation of the polyethylene terephthalate template: The design and cutting of the template are carried out by using a TR-9060 type laser cutting machine.

[0053] Example 1 A preparation method of a modular integrated stretchable electrochromic device array is as follows: (1) Preparation of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based adhesion substrate: Weigh 4 g of acrylamide, 4 g of 2-acrylamido-2-methylpropanesulfonic acid and 6 g of glycerol in a beaker, add 14 g of deionized water, and stir for 30 min to form a homogeneous mixed solution; then add 0.34 g of polyvinylpyrrolidone, 0.025 g of N,N-methylenebisacrylamide and 0.036 g of ammonium persulfate to the mixed solution, continue to stir for 30 min, then transfer it to a conventional mold, place it in an oven at 60 °C for 60 min, and then at 80 °C, continue to keep warm for 30 min and then take it out, and let it cool naturally to room temperature to obtain acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel; (2) Preparation of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel: Weigh 5 g of acrylamide, 1.2 g of 2-acrylamido-2-methylpropanesulfonic acid and 2.95 g of lithium chloride in a beaker, add 20 g of deionized water, and stir for 30 min to form a homogeneous mixed solution; then add 0.34 g of polyvinylpyrrolidone, 0.025 g of N,N-methylenebisacrylamide and 0.036 g of ammonium persulfate to the mixed solution, continue to stir for 30 min, then transfer it to a conventional mold, place it in an oven at 60 °C for 60 min, and then at 80 °C, continue to keep warm for 30 min and then take it out, and let it cool naturally to room temperature to obtain 2-acrylamido-2-methylpropanesulfonic acid / acrylamide / acrylic acid / lithium chloride hydrogel; (3) Preparation of tungsten oxide quantum dot solution: Dissolve 8.25 g of sodium tungstate dihydrate in 25 g of deionized water solution, and add concentrated hydrochloric acid (37%) solution after complete dissolution to form a white precipitate; then centrifuge at a speed of 8000 r / min for 5 min, remove the supernatant solution, and wash the precipitate with deionized water until the pH of the precipitate ≥ 3; then, mix the precipitate with 30 mL of ethylene glycol, stir and mix at 90 °C to form a transparent and colorless solution, transfer it to a 100 mL polytetrafluoroethylene reaction kettle, heat and react in an oven at 180 °C for 48 h, and cool to room temperature; place the obtained solution in a dialysis bag with a molecular weight of 1000 for dialysis treatment for 24 h to remove impurities in the solution, and take out the solution to obtain tungsten oxide quantum dot solution; (4) Polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate conductive hydrogel: Weigh 4.8 g of polyvinyl alcohol, 6 g of acrylic acid and 12 g of glycerol into a beaker, add 24 g of deionized water, and stir on a heating table at 90 °C for 30 min to form a uniform and transparent mixed solution; then transfer the solution to a conventional mold, place it in a -18 °C refrigerator and freeze for 4 h, then take it out and thaw at room temperature for 3 h, repeat this cycle 4 times, and finally dry naturally for 48 h to obtain polyvinyl alcohol / acrylic acid / glycerol hydrogel; Spin-coat poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate on the surface of the polyvinyl alcohol / acrylic acid / glycerol hydrogel. The spin-coating process is a spin speed of 2000 r / min, a spin time of 60 s, annealing at 80 °C for 5 min, and natural cooling to room temperature to obtain a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate conductive hydrogel conductive electrode; (5) Preparation of tungsten oxide quantum dots / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate composite electrochromic solution: Weigh 1 g of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate solution, 2 g of tungsten oxide quantum dot solution and 0.025 g of Triton-X100 solution, add them to 1 g of deionized water and mix them to form a mixed solution, and continuously stir for 24 h to prepare a tungsten oxide quantum dots / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate composite electrochromic solution; (6) Preparation of polyethylene terephthalate template: Prepare a 3.5 * 3.5 cm circular template as shown in Figure 2 by laser cutting. There are 8 square holes of 3 * 3 mm on the circle. Laser cutting process parameters: processing power: 14%, turning power: 14%, processing speed: 30 mm / s, processing times: 3 times; (7) Preparation of modular electrochromic unit: Place the template prepared in (6) on the surface of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel, and dropwise coat the tungsten oxide quantum dots / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate electrochromic solution into 8 square frames of 3 * 3 mm. After annealing treatment in an oven at 80 °C for 5 min, 8 square electrochromic units are formed on the surface of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel. Remove the polyethylene terephthalate template, and use a paper cutter to cut the hydrogel coated with electrochromic units into 8 equal modular electrochromic unit hydrogels, and take 6 of the modular electrochromic unit hydrogels for standby; (8) The microcontroller is a conventional product, such as Figure 3The structure shown is a microcontroller with six open-circuit ports. The microcontroller is composed of a printed circuit board and a microchip. The printed circuit board is purchased from Shenzhen Jiali Technology Group Co., Ltd., and the microchip is purchased from Shenzhen Lichuang E-commerce Co., Ltd. The microcontroller can be obtained through conventional soldering. (9)Preparation of the stretchable modular electrochromic device: The acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate, the microcontroller, the modular electrochromic unit, and the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel-based conductive electrode are compounded to prepare a stretchable modular electrochromic device. Among them, the thicknesses of the acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate, the modular tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid-acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / lithium chloride electrochromic unit, and the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel-based conductive electrode are all 1 mm, and the thickness of the microcontroller is 0.5 mm. Specifically, the microcontroller is placed on the acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate, and then 6 modular electrochromic units are placed to cover the 6 open-circuit ports respectively; then the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel-based conductive electrode is placed to obtain the stretchable modular electrochromic device of the present invention. Figure 4 It is a schematic diagram of the structure of the stretchable modular electrochromic device. As common knowledge, the controller is conventionally provided with leads for connecting electricity. For the sake of simplicity, the leads are not shown in the drawings.

[0054] Figure 5 It is a flowchart of the operation of the stretchable modular electrochromic device.

[0055] Figure 6 It is the transmittance curve, shear strength, hydrogel air permeability characterization, and comparison chart of the air permeability of the hydrogel with other commercial materials of the acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based adhesion substrate. It can be seen that the transmittance of the acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel at 550 nm is above 95%, the shear strength is 24.7 kPa, and when placed at 35 °C and 40% humidity for 48 h, the water loss rate is 13%. It has excellent air permeability compared with other adhesion materials.

[0056] Figure 7Regarding the conductivity, transmittance curve, ionic conductivity, and mechanical tensile properties of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride ion-conductive hydrogel, it can be seen that the transmittance of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride ion-conductive hydrogel at 550 nm is 92%, and the ionic conductivity is 2.84 S cm -1 , and the elongation at break of the hydrogel is above 250%, and the breaking strength is 103 kPa. Among them, when the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride ion-conductive hydrogel is used as a conductor and connected to a power source and a small light bulb to form a closed circuit, when the elongation of the hydrogel is 100%, the small light bulb can still be kept lit, verifying its excellent conductivity.

[0057] Figure 8 Regarding the resistance comparison of the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel with other hydrogels, the resistance and transmittance changes at different spin-coating speeds, the resistance changes after standing at room temperature for different times, and the resistance changes after stretching cycles at 100% elongation, it can be seen that the resistance of the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel is 44 Ω, the transmittance of the hydrogel prepared under the condition of 2000 r / min is 78%, the resistance after standing at room temperature for 400 h is 38 Ω, and the resistance increases from 42 Ω to 354 Ω after 10000 stretching cycles at 100% elongation.

[0058] Figure 9 Regarding the optical photos of the bend and twist of the stretchable modular electrochromic device, it can be seen that the device can achieve a large degree of bending and twisting, and still has electrochromic performance after bending and twisting.

[0059] Figure 10 Regarding the optical photos before and after stretching and the electrochromic behavior after stretching of the stretchable modular electrochromic device at a stretching elongation of 80%; it can be seen that the device still exhibits excellent electrochromic behavior after multiple cycles at a stretching elongation of 80%.

[0060] Figure 11 Regarding the optical photos, optical contrast, and response time curve of the color change behavior of the stretchable modular electrochromic unit, it can be seen that the optical contrast of the color change of the stretchable modular electrochromic unit is 43%, and the electrochromic and fading response times are both 2 s.

[0061] Figure 12Regarding the response behavior of the stretchable modular electrochromic device to different voltages, it can be seen that the device can produce color-changing behaviors of different numbers of modular electrochromic units at different voltages. The specific process is as follows: First, connect the G and V ports of the microcontroller to the negative and positive poles of the power supply respectively to supply power to the microcontroller and make it work. Connect wires to the A and G ports respectively as the input terminals of the sensor. Subsequently, layer by layer attach the microcontroller, the modular electrochromic unit hydrogel, and the hydrogel electrode onto the adherent hydrogel substrate, and through the self-adhesive property, the device assembly can be achieved by simple pressing. Lead out another wire from the negative pole of the power supply and connect it to the corner of the hydrogel electrode of the device to complete the device assembly. Its working mechanism is as follows: The microcontroller has six output ports, and the on / off of the microcontrol ports can be controlled through program programming. The specific effects are shown in Table 1. By regulating the voltage at the input terminal of the sensor, the number of on / off of the microcontroller ports can be controlled, thereby achieving different numbers of color changes of the modular electrochromic units.

[0062] Table 1 Microcontroller Port On / Off and External Sensor Voltage Parameters

[0063] Example 2 On the basis of Example 1, change step (4), replace acrylic acid with glacial acetic acid, and the rest remains the same, to obtain polyvinyl alcohol / glacial acetic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate conductive hydrogel.

[0064] Figure 8 Regarding the resistance comparison between polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate hydrogel and other hydrogels, the resistance and transmittance changes at different spin-coating speeds, the resistance changes after standing at room temperature for different times, and the resistance changes after stretching cycles at 100% elongation, it can be seen that the resistance of polyvinyl alcohol / glacial acetic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate hydrogel is 50 Ω.

[0065] Example 3 On the basis of Example 1, change step (4), the spin-coating speed is 1000 r / min, and the rest remains the same, to obtain polyvinyl alcohol / glacial acetic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate conductive hydrogel.

[0066] Figure 8For the resistance comparison of polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel with other hydrogels, the resistance and transmittance changes at different spin-coating speeds, the resistance changes after standing at room temperature for different times, and the resistance changes after stretching cycles at 100% tensile elongation, it can be seen that under the condition of a spin-coating speed of 1000 r / min, the resistance of the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel is 31 Ω and the transmittance is 68%.

[0067] Example 4 On the basis of Example 1, step (4) was changed, the spin-coating speed was 3000 r / min, and the rest was the same, to obtain a polyvinyl alcohol / glacial acetic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel.

[0068] Figure 8 For the resistance comparison of polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel with other hydrogels, the resistance and transmittance changes at different spin-coating speeds, the resistance changes after standing at room temperature for different times, and the resistance changes after stretching cycles at 100% tensile elongation, it can be seen that under the condition of a spin-coating speed of 3000 r / min, the resistance of the polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel is 78 Ω and the transmittance is 80%.

[0069] The present invention synthesizes hydrogels with various functions by regulating the raw material ratio and types. By constructing and designing a modular and multi-layer composite structure, a simple, rapid, stretchable integrated flexible electrochromic device is prepared. The device exhibits excellent bending, twisting and stretching properties, and has excellent response speed and optical contrast, and can realize the visual response behavior to voltage. It has broad application prospects in wearable intelligent display and medical health visual monitoring.

[0070] The present invention discloses a modular integrated stretchable electrochromic device array and a preparation method thereof, including a hydrogel-based adhesive substrate, an ion-conductive hydrogel, an electrochromic unit, a microcontroller, and a hydrogel-based conductive electrode. The hydrogel-based adhesive substrate is an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel with excellent adhesion, stretchability, and transparency. The ion-conductive hydrogel is an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel with excellent ionic conductivity, stretchability, and transparency. The electrochromic layer is a uniform composite layer formed by drop-coating a mixture of tungsten oxide quantum dots prepared by a hydrothermal method and a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution on the surface of the hydrogel. The hydrogel-based electrode is a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid hydrogel with excellent electronic conductivity, stretchability, and transparency. In the present invention, the flexible and stretchable electrochromic array can achieve simple and rapid integration of the device by relying on the self-adhesion performance between hydrogels and the modular structure design, showing excellent stability, and having excellent response speed, good optical contrast, and visual response to voltage.

[0071] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A modular integrated stretchable electrochromic device array, characterized in that, It includes a hydrogel-based flexible adhesion substrate, an electrochromic unit, a microcontroller, and a hydrogel-based conductive electrode arranged in sequence.

2. A substrate for a modular integrated stretchable electrochromic device array, characterized in that, It includes a hydrogel-based flexible adhesion substrate, a modular electrochromic unit, and a hydrogel-based conductive electrode arranged in sequence.

3. The modular integrated stretchable electrochromic device array according to claim 1 or the substrate for the modular integrated stretchable electrochromic device array according to claim 2, characterized in that, The hydrogel-based flexible adhesion substrate is an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate; the electrochromic unit includes an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel and a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic layer on its surface; the hydrogel-based conductive electrode is a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel.

4. The modular integrated stretchable electrochromic device array according to claim 1, characterized in that, The number of electrochromic units is not greater than the number of ports of the microcontroller.

5. The preparation method of the modular integrated stretchable electrochromic device array according to claim 1, characterized in that, It includes the following steps: The hydrogel-based adhesion substrate, the electrochromic unit, the microcontroller, and the hydrogel-based conductive electrode are assembled in sequence by a layer-by-layer assembly method to obtain a modular integrated stretchable electrochromic device array.

6. The preparation method of the modular integrated stretchable electrochromic device array according to claim 5, characterized in that, Using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and glycerol as raw materials, prepare an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / glycerol hydrogel-based flexible adhesion substrate; using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and lithium chloride as raw materials, prepare an acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel, mix tungsten oxide quantum dots with a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution and a surfactant to prepare a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution, and coat the tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution on the surface of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / lithium chloride hydrogel to form an electrochromic unit; using polyvinyl alcohol, acrylic acid, glycerol, and a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution as raw materials, prepare a polyvinyl alcohol / acrylic acid / glycerol / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel.

7. The preparation method of the modular integrated stretchable electrochromic device array according to claim 6, wherein, Acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, glycerol, initiator, N,N'-methylenebisacrylamide, surfactant and water are mixed to form a solution, and then dried to obtain an acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / glycerol hydrogel-based flexible adhesion substrate; acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, lithium chloride, initiator, N,N'-methylenebisacrylamide, surfactant and water are mixed to form a solution, and then dried to obtain acrylamide / 2-acrylamido-2-methylpropane sulfonic acid / lithium chloride hydrogel; hydrochloric acid solution is dropped into an aqueous solution of sodium tungstate dihydrate until precipitation occurs, and then the precipitate is taken and added to ethylene glycol to form a transparent solution, and heated to react to obtain a tungsten oxide quantum dot solution; the tungsten oxide quantum dot solution, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid solution, ethylene glycol and surfactant are mixed to prepare a tungsten oxide quantum dot / poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid electrochromic solution; polyvinyl alcohol, acrylic acid, glycerol and water are mixed to form a solution, and then freeze-thawed to obtain polyvinyl alcohol / acrylic acid / glycerol hydrogel, and then a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid film is formed on the surface of the polyvinyl alcohol / acrylic acid / glycerol hydrogel by spin coating, and after annealing treatment, a poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid conductive hydrogel is prepared.

8. Use of the modular integrated stretchable electrochromic device array according to claim 1 or the substrate for the modular integrated stretchable electrochromic device array according to claim 2 in the preparation of electronic devices.

9. Use of the modular integrated stretchable electrochromic device array according to claim 1 in the preparation of flexible modular color-changing devices or as a flexible modular color-changing device.

10. Use of the modular integrated stretchable electrochromic device array according to claim 1 in the preparation of health monitoring and medical diagnostic devices.

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