Method for manufacturing stretchable color-changing element and stretchable color-changing element manufactured by the method

Abstract

The present invention relates to a method for manufacturing a stretchable color-changing element and a stretchable color-changing element manufactured thereby. More specifically, the stretchable color-changing element is manufactured by stretching a color-changing polymer gel and then coating one and / or the other side of the gel with a metal solution. The stretchable color-changing element has excellent water resistance and initial transmittance.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a stretchable color-changing element and a stretchable color-changing element manufactured thereby, and more particularly, to a stretchable color-changing element manufactured by stretching a color-changing polymer gel and then coating one and / or the other side of the stretchable color-changing element with a metal solution, which is characterized by having excellent water resistance and initial transmittance. [Background technology]

[0002] Electrochromism is a phenomenon where the hue changes reversibly depending on the direction of the electric field when a voltage is applied, and a material whose optical properties change reversibly due to an electrochemical redox reaction is called an electrochromic material. Such electrochromic materials have the property that they are colorless unless an external electric signal is applied, and become colored when an electric signal is applied, or conversely, they are colored unless an external signal is applied, and the color disappears when a signal is applied.

[0003] An electrochromic device is a device that changes the light transmission characteristics by changing the color of an electrochromic material through an electrical redox reaction when a voltage is applied. Currently, there is an increasing demand for electrochromic devices that selectively transmit light in various technical fields. Such electrochromic devices are applied in various fields such as smart windows, smart mirrors, display devices, and camouflage devices.

[0004] Therefore, various technologies related to electrochromic devices have been developed. For example, Patent Document 1 (applicant: LG Electronics Inc.) relates to an electrochromic element with improved color change speed. The present invention provides an electrochromic element including a first transparent electrode, a second transparent electrode facing the first transparent electrode, a first bus electrode of a predetermined pattern formed on an upper surface of the first transparent electrode, an electrolyte layer located between the first bus electrode and the second transparent electrode, a first electrochromic layer located between the first transparent electrode and the electrolyte layer and in contact with the electrolyte layer, and a passivation layer formed between the first bus electrode and the electrochromic layer to prevent contact between the first bus electrode and the electrochromic layer and surrounding the first bus electrode.

[0005] However, the electrochromic device (element) or electrochromic element using polymer gel generally has poor stability against water, and research to overcome this problem is being continuously conducted. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Korean Patent Publication No. 10-2017-0115864 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides a method for producing a stretchable color-changing element having excellent stability against water.

[0008] The present invention also provides a stretchable color-changing element produced by the method for producing a stretchable color-changing element.

[0009] The present invention also provides a product comprising the stretchable color-changing element. [Means for solving the problem]

[0010] As a technical means for achieving the above-mentioned technical object, one aspect of the present invention is to The present invention provides a method for manufacturing a stretchable color-changing element, the method including the steps of stretching a polymer gel, coating one surface of the stretched polymer gel with a metal solution, and recovering the stretched polymer gel.

[0011] The polymer gel includes a polymer resin, a plasticizer, an ionic liquid, a color changing material, and a reducing agent.

[0012] The polymer resin includes a polymer resin selected from the group consisting of polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyurethane (PU), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), polyimide (PI), polyethylene terephthalate (PET), and combinations thereof.

[0013] The ionic liquid includes an ionic liquid selected from the group consisting of neutral liquids, anionic liquids, cationic liquids, and combinations thereof.

[0014] The neutral liquid includes a neutral liquid selected from the group consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (Emim TFSI), 1-methyl-3-propylimidazolium iodide (MPII), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf), 1-ethyl-3-methylimidazolium hydrogen sulfate (EMIHSO4), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf), N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRTFSI), and combinations thereof.

[0015] The anionic liquid is trifluoroacetic acid ([tfa] - ), trifluoromethanesulfonate ([CF3SO3] - ) and bis(fluorosulfonyl)imide ([N(SO2F)2] - ) and bis(trifluoromethanesulfonyl)imide ([N(SO2CF3)2] - ) and dicyanamide ([N(CN)2] - ) and tetracyanoborate ([B(CN)4] - ) and dihydrogen phosphate ([H2PO4] - ) and hydrogen sulfate ([HSO4] - ) and combinations thereof.

[0016] The cationic liquid comprises a cationic liquid selected from the group consisting of imidazolium, pyrrolidinium, piperidinium alkylmethylimidazolium, and combinations thereof.

[0017] The content of the ionic liquid is 40 to 140 parts by weight, the content of the plasticizer is 300 to 1,500 parts by weight, and the contents of the color changing material and the reducing agent are each 10 to 140 parts by weight, relative to 100 parts by weight of the polymer resin.

[0018] The polymer gel is stretched by 20% to 80% of the length of the polymer gel.

[0019] The metal solution includes a solution of a metal selected from the group consisting of silver (Ag), gold (Au), platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), osmium (Os), and combinations thereof.

[0020] The concentration of the metal solution is between 1 mg / mL and 20 mg / mL.

[0021] The method for manufacturing the stretchable color-changing element further includes a step of coating one side of the stretched polymer gel with a metal solution, and then spraying water onto the surface of the gel coated with the metal solution to anneal the surface.

[0022] The annealing is carried out for 10 seconds to 1 minute.

[0023] The recovery of the polymer gel is carried out at a speed of 0.01 mm / s to 5.0 mm / s.

[0024] The method for manufacturing the stretchable color-changing element further includes a step of recovering the stretched polymer gel, and then performing the same process on the other side of the polymer gel.

[0025] Another aspect of the present invention provides a stretchable color-changing element manufactured by the method for manufacturing a stretchable color-changing element, and a product including the stretchable color-changing element. Effect of the Invention

[0026] The stretchable color-changing element manufactured by the manufacturing method of the stretchable color-changing element according to the present invention has excellent stability against water because it is manufactured by stretching the color-changing polymer gel and then coating one and / or the other side of the gel with a metal solution.

[0027] In addition, the stretchable color-changing element has excellent initial transmittance and is stable against any deformation, so that the performance as a color-changing element is maintained. [Brief description of the drawings]

[0028] [Figure 1] 1 is a flow chart illustrating a method for manufacturing a stretchable color-changing element according to an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram showing a method for manufacturing a stretchable color-changing element according to an embodiment of the present invention. [Diagram 3] 1 is a photograph showing the water stability of a stretchable color-changing element manufactured according to an embodiment of the present invention. [Figure 4]1 is a graph showing water stability of a stretchable color-changing element manufactured according to an embodiment of the present invention. [Diagram 5] 1 is a graph showing the transmittance over time of a stretchable color-changing element manufactured according to an embodiment of the present invention. [Figure 6] 1 is a graph showing the optical density as a function of charge density of a stretchable pigment molecule manufactured according to an embodiment of the present invention. [Figure 7] 1 is a photograph showing a modified example of a stretchable pigment molecule manufactured according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather as defined only by the claims set forth below.

[0030] In addition, the terms used in the present invention are merely used to describe certain embodiments and are not intended to limit the present invention. A singular surface includes a plural expression unless the context clearly indicates otherwise. Throughout the present specification, "comprising" a certain component means that it further includes other components, not excluding other components, unless otherwise specified to the contrary.

[0031] A first aspect of the present application provides a method for manufacturing a stretchable color-changing element, the method including the steps of stretching a polymer gel, coating one side of the stretched polymer gel with a metal solution, and recovering the stretched polymer gel.

[0032] Hereinafter, a method for manufacturing a stretchable color-changing element according to a first aspect of the present application will be described in detail step by step with reference to Figures 1 and 2. Hereinafter, Figure 1 is a flow chart showing a method for manufacturing a stretchable color-changing element according to an embodiment of the present invention, and Figure 2 is a schematic diagram showing a method for manufacturing a stretchable color-changing element according to the present invention.

[0033] Meanwhile, since the configurations shown in Figures 1 and 2 are merely examples, it should be understood that any modifications of the form or replacement of the components are included within the scope of the present invention. First, in one embodiment of the present invention, the method for manufacturing the stretchable color-changing element includes a step S10 of stretching a polymer gel.

[0034] In one embodiment of the present application, the polymer gel is stretched by 20% to 80% of the length of the polymer gel, and in one embodiment of the present invention, it is stretched by 50%. At this time, the degree of stretching is a percentage (%) of the original length of the polymer gel, for example, if the length of the polymer gel is 5 cm and it is stretched by 50%, the length of the stretched polymer gel is 7.5 cm. Meanwhile, the polymer gel is stretched by applying a certain force in the length direction, and both ends are fixed to maintain the length of the stretched polymer gel.

[0035] In an embodiment of the present disclosure, the polymer gel includes a polymer resin, a plasticizer, an ionic liquid, a color changing material, and a reducing agent.

[0036] In one embodiment of the present application, the polymer resin is plasticized without a solvent and includes a polymer resin selected from the group consisting of polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyurethane (PU), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), polyimide (PI), polyethylene terephthalate (PET), and combinations thereof.

[0037] In one embodiment of the present application, the plasticizer is a material that plasticizes the polymer resin at a certain temperature and has a flash point of 200° C. or more. Meanwhile, according to one embodiment of the present invention, the plasticizer is dibutyl adipate (DBA), which is represented by the following Chemical Formula 1:

[0038] [ka]

[0039] In an embodiment of the present application, the ionic liquid refers to a liquid containing ions, and includes, for example, a neutral liquid, an anionic liquid, or a cationic liquid.

[0040] In one embodiment of the present application, the neutral liquid includes a neutral liquid selected from the group consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (Emim TFSI), 1-methyl-3-propylimidazolium iodide (MPII), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf), 1-ethyl-3-methylimidazolium hydrogen sulfate (EMIHSO4), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf), N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRTFSI), and combinations thereof.

[0041] In one embodiment of the present application, the anionic liquid is trifluoroacetic acid ([tfa] - ), trifluoromethanesulfonate ([CF3SO3] - ) and bis(fluorosulfonyl)imide ([N(SO2F)2] - ) and bis(trifluoromethanesulfonyl)imide ([N(SO2CF3)2] - ) and dicyanamide ([N(CN)2] - ) and tetracyanoborate ([B(CN)4] -) and dihydrogen phosphate ([H2PO4] - ) and hydrogen sulfate ([HSO4] - ) and combinations thereof.

[0042] In one embodiment of the present application, the cationic liquid includes a cationic liquid selected from the group consisting of imidazolium, pyrrolidinium, piperidinium alkylmethylimidazolium, and combinations thereof.

[0043] Meanwhile, according to one embodiment of the present invention, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (Emim TFSI), which is represented by the following Chemical Formula 2.

[0044] [ka]

[0045] In one embodiment of the present application, the color change material is a material used to change the color of the polymer gel, and according to one embodiment of the present invention, DHV[TFSI]2 is used, but is not limited to this. Meanwhile, the DHV[TFSI]2 is represented by the following chemical formula 3.

[0046] [ka]

[0047] In one embodiment of the present disclosure, the reducing agent is a material that reduces a target material, and according to one embodiment of the present disclosure, dimethylferrocene is used, but is not limited thereto. Meanwhile, the dimethylferrocene is represented by the following Chemical Formula 4:

[0048] [ka]

[0049] In one embodiment of the present application, the content of the ionic liquid is 40 to 140 parts by weight, the content of the plasticizer is 300 to 1,500 parts by weight, and the content of the color changing material and the reducing agent is 10 to 140 parts by weight, respectively, relative to 100 parts by weight of the polymer resin. Preferably, the content of the ionic liquid is 100 to 140 parts by weight, the content of the plasticizer is 800 to 1,000 parts by weight, and the content of the color changing material and the reducing agent is 10 to 120 parts by weight, respectively. Meanwhile, according to one embodiment of the present invention, the weight content ratio of the polymer resin, the plasticizer, the ionic liquid, the color changing material, and the reducing agent is 1:9:1.2:0.7061:0.1652. If the content of the constituent materials deviates from the above range, there is a possibility that the ionic conductivity, the color changing speed, and the decoloring speed of the polymer gel may be reduced.

[0050] Next, in an embodiment of the present disclosure, the method for manufacturing the stretchable color-changing element includes a step S20 of coating one surface of the stretched polymer gel with a metal solution.

[0051] In an embodiment of the present application, the coating may be performed by any common coating method without limitation, for example, by spraying a metal solution.

[0052] According to an embodiment of the present application, the metal solution includes a solution of a metal selected from the group consisting of silver (Ag), gold (Au), platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), osmium (Os), and combinations thereof, and preferably, a silver (Ag) nanowire solution is used. In this case, when the silver (Ag) nanowire solution is used, a polymer such as polyvinylpyrrolidone (PVP) is used in the manufacturing process, and the size of the silver nanowire is an average diameter of 30 nm and an average length of 20 um. Meanwhile, the metal solution means a solution in which the metal is dissolved in a solvent, and the solvent may be ethanol, water, isopropyl alcohol, or the like, but is not limited thereto, and according to an embodiment of the present invention, ethanol is used. Meanwhile, the concentration of the metal solution is 1 mg / mL to 20 mg / mL, preferably 1 mg / mL to 10 mg / mL, and about 5 mg / mL according to an embodiment of the present invention. If the concentration of the metal solution is less than 1 mg / mL, the content of the metal contained therein is relatively too small, which may result in a decrease in performance as a color-changing element, whereas if the concentration exceeds 20 mg / mL, the content of the metal contained therein is relatively too large, which may result in a decrease in dispersion stability.

[0053] In one embodiment of the present disclosure, the method for manufacturing the stretchable color-changing element includes a step of spraying water onto one surface of the polymer gel coated with the metal solution, and annealing the surface.

[0054] In one embodiment of the present application, the water injection and annealing are performed simultaneously. The annealing is performed for 10 seconds to 1 minute, preferably 20 seconds to 40 seconds, and in one embodiment of the present invention, for about 30 seconds. If the annealing is performed for less than 10 seconds, the time may be too short and the annealing may not be sufficient, and if it is performed for more than 1 minute, there may be a problem of the coated metal being peeled off.

[0055] Next, in an embodiment of the present disclosure, the method for manufacturing the stretchable color-changing element includes a step S30 of recovering the stretched polymer gel.

[0056] In an embodiment of the present application, the recovery step is a step of recovering the length of the stretched polymer gel to its original length by performing the annealing process simultaneously.

[0057] In an embodiment of the present application, the polymer gel is restored at a speed of 0.01 mm / s to 5.0 mm / s, but is not limited thereto, and may be restored at a speed that can be appropriately changed depending on the original length of the polymer gel.

[0058] In one embodiment of the present disclosure, the method for manufacturing the stretchable color-changing element further includes performing the same steps (S10 to S30) on another side of the polymer gel.

[0059] In one embodiment of the present disclosure, the method for manufacturing the stretchable color-changing element described above coats the metal solution on only one side of the polymer gel, but the metal solution may also be coated on the other side.

[0060] More specifically, the method further includes recovering the stretched polymer gel, then further stretching the recovered polymer gel, coating the other side of the stretched polymer gel with a metal solution, and recovering the stretched polymer gel. As a result, as shown in FIG. 2, the stretchable color-changing element has a form in which both sides of the polymer gel are coated with a metal solution.

[0061] A second aspect of the present application provides a stretchable color-changing element manufactured by the method for manufacturing a stretchable color-changing element according to the first aspect of the present application, and a product including the stretchable color-changing element.

[0062] Detailed descriptions of parts that overlap with the first aspect of the present application have been omitted, but the contents described with respect to the first aspect of the present application will apply equally even if the description is omitted in the second aspect.

[0063] The stretchable color-changing element and the product including the same according to the second aspect of the present application will now be described in detail.

[0064] In one embodiment of the present application, the stretchable color-changing element is manufactured by stretching a color-changing polymer gel and then coating one and / or the other side of the gel with a metal solution, so that the stretchable color-changing element has excellent stability against water. In addition, the stretchable color-changing element has excellent initial transmittance and is stable against any deformation, so that the performance of the color-changing element is smoothly maintained.

[0065] In one embodiment of the present application, the product including the stretchable color-changing element may be applied to any product that requires a stretchable color-changing element, for example, architectural window glass, smart windows, vehicle mirrors, displays, or electronic shelf labels (ESLs).

[0066] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to exemplary embodiments thereof, so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0067] Example: Manufacture of stretchable color-changing elements by stretching 1. Manufacturing of PVC discoloration gel Polyvinyl chloride (PVC) was added and dissolved in tetrahydrofuran (THF) stirred at 400 rpm with a magnetic bar. The ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM] [TFSI], the color changing material DHV [TFSI] 2, and the reducing agent dimethylferrocene were added to the solution, and finally the plasticizer dibutyl adipate (DBA) was added and thoroughly stirred for 12 hours. At this time, the weight mixing ratio of the PVC, DBA, [EMIM] [TFSI], DHV [TFSI] 2, and dimethylferrocene was 1:9:1.2:0.7061:0.1652. Next, the solution was poured into a Petri dish and dried at room temperature for 48 hours to produce a PVC color changing gel.

[0068] 2. Fabrication of stretchable color-changing element As shown in Figure 2, a stretchable color-changing element was manufactured. In detail, the PVC color-changing gel manufactured in 1 was cut into a size of 5 cm x 6 cm, and then cut into a thickness of 0.5 mm and stretched by 50% of the original length.

[0069] Next, a silver nanowire solution (concentration: 5 mg / mL) mixed with ethanol was placed in an air spray and sprayed onto one side of the stretched PVC discoloration gel to coat the silver nanowires (height: 15 cm / spray pressure: 1 psi).

[0070] Next, after the coated solution was dried, water was sprayed onto the coated surface to anneal it for 30 minutes, and at the same time, the length of the stretched PVC gel was restored at a speed of 0.5 mm / s.

[0071] Finally, the opposite side of the PVC gel coated with the silver nanowires was coated with silver nanowires by the same process to prepare a stretchable color-changing element.

[0072] Experimental example 1. Evaluation of water resistance In order to evaluate the water resistance of the stretchable color-changing element manufactured according to the above embodiment, the color-changing element was immersed in water and the change in volume was measured, which is shown in FIG. 3, and the transmittance over time was measured, which is shown in FIG. 4.

[0073] As shown in FIG. 3, it was confirmed that the stretchable color-changing element manufactured according to the embodiment of the present invention did not change in volume even after being immersed in water for about a day.

[0074] In addition, as shown in FIG. 4, it was confirmed that the transmittance of the stretchable color-changing element manufactured according to the embodiment of the present invention did not change significantly with time before and after immersion in water.

[0075] It was analyzed that this is because the stretchable color-changing element according to the present invention is made of a non-aqueous-based material.

[0076] Experimental Example 2: Evaluation of the optical performance of stretchable colorimeters The transmittance of the stretchable color-changing element prepared in the above example was measured before and after stretching as a function of time, and the results are shown in FIG.

[0077] As shown in FIG. 5, it was confirmed that the initial transmittance increased when the stretchable color-changing element was stretched.

[0078] In addition, the optical density of the stretchable color-changing element prepared in the above example was measured before and after stretching according to the charge density, and the results are shown in FIG.

[0079] As shown in FIG. 6, it was confirmed that the color change amount, color change speed, and decolorization speed decreased when the stretchable color-changing element was stretched. This was analyzed to be due to an increase in the resistance of the electrodes.

[0080] Experimental Example 3. Evaluation of the stability of elastic metamorphic molecules The stretchable color-changing element prepared in the above example was evaluated for stability when deformed in various ways, and the results are shown in FIG.

[0081] As shown in FIG. 7, it was confirmed that the stretchable color-changing element manufactured according to the embodiment of the present invention was stable even when deformed in various ways, and the performance as a color-changing element was also maintained.

[0082] Although the present invention has been described in detail above with reference to the drawings and preferred embodiments, the scope of the technical idea of ​​the present invention is not limited to these drawings and embodiments. Therefore, there are various modifications or equivalent embodiments within the scope of the technical idea of ​​the present invention. Therefore, the scope of the technical idea of ​​the present invention should be interpreted according to the claims, and any technical idea equivalent to or within the equivalent scope should be interpreted as belonging to the scope of the present invention.

[0083] This patent is the result of the Korea Research Foundation's (NRF-2021R1A2C201198) grant for "Application of next-generation transparent stretchable sensors and electrochemical display devices using non-aqueous, high-performance, and multifunctional ion-conductive and non-ion-conductive polymer gels."

Claims

1. stretching the polymer gel; coating one surface of the stretched polymer gel with a metal solution; recovering the stretched polymer gel; A method for producing a stretchable color-changing element comprising the steps of:

2. The method for producing a stretchable color-changing element according to claim 1 , wherein the polymer gel contains a polymer resin, a plasticizer, an ionic liquid, a color-changing substance, and a reducing agent.

3. The polymer resin is selected from the group consisting of polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyurethane (PU), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), polyimide (PI), polyethylene terephthalate (PET), and combinations thereof. The method for producing a stretchable color-changing element according to claim 2.

4. The method for producing a stretchable color-changing element according to claim 2 , wherein the ionic liquid comprises an ionic liquid selected from the group consisting of a neutral liquid, an anionic liquid, a cationic liquid, and a combination thereof.

5. The neutral liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (Emim TFSI), 1-methyl-3-propylimidazolium iodide (MPII), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF ４ ), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf), and 1-ethyl-3-methylimidazolium hydrogen sulfate (EMIHSO ４ 5. The method for producing a stretchable color-changing element according to claim 4, comprising a neutral liquid selected from the group consisting of N-methyl-N-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRTFSI) and combinations thereof.

6. The anionic liquid is trifluoroacetic acid ([tfa] － ), trifluoromethanesulfonate ([CF ３ SO ３ ] － ) and bis(fluorosulfonyl)imide ([N(SO ２ F) ２ ] － ) and bis(trifluoromethanesulfonyl)imide ([N(SO ２ CF ３ ) ２ ] － ) and dicyanamide ([N(CN) ２ ] － ) and tetracyanoborate ([B(CN) ４ ] － ) and dihydrogen phosphate ([H ２ P.O. ４ ] － ) and hydrogen sulfate ([HSO ４ ] － 5. The method for producing the stretchable color-changing element according to claim 4, comprising an anionic liquid selected from the group consisting of:

7. The method for producing a stretchable color-changing element according to claim 4, wherein the cationic liquid comprises a cationic liquid selected from the group consisting of imidazolium, pyrrolidinium, piperidinium alkylmethylimidazolium, and combinations thereof.

8. For 100 parts by weight of the polymer resin, The content of the ionic liquid is 40 to 140 parts by weight, The content of the plasticizer is 300 parts by weight to 1,500 parts by weight, The method for manufacturing a stretchable color-changing element according to claim 2, wherein the content of the color-changing material and the content of the reducing agent are each 10 to 140 parts by weight.

9. The method for manufacturing a stretchable color-changing element according to claim 1, wherein the polymer gel is stretched by 20% to 80% of the length of the polymer gel.

10. The metal solution is selected from the group consisting of silver (Ag), gold (Au), platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh), ruthenium (Ru), osmium (Os), and combinations thereof. The method for producing a stretchable color-changing element according to claim 1, comprising:

11. The method for producing a stretchable color-changing element according to claim 1 , wherein the concentration of the metal solution is 1 mg / mL to 20 mg / mL.

12. The method for producing the stretchable color-changing element includes the steps of: coating one surface of the stretched polymer gel with a metal solution; and annealing the surface of the gel coated with the metal solution by spraying water; The method for producing the stretchable color-changing element according to claim 1 , further comprising:

13. The method for manufacturing a stretchable color-changing element according to claim 12, wherein the annealing is performed for 10 seconds to 1 minute.

14. The method for producing a stretchable color-changing element according to claim 1 , wherein the polymer gel is restored at a speed of 0.01 mm / s to 5.0 mm / s.

15. The method for producing the stretchable color-changing element includes the steps of: recovering the stretched polymer gel; and then performing the same process on the other side of the polymer gel; The method for producing the stretchable color-changing element according to claim 1 , further comprising:

16. A stretchable color-changing element produced by the method for producing a stretchable color-changing element according to claim 1.

17. 17. An article of manufacture comprising the stretchable color-changing element of claim 16.

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