Flexible fibrous infrared emissivity modulation device and method of making same

Abstract

The application relates to a flexible fiber-like infrared emissivity regulating device and a preparation method thereof. The device is coated with an ion gel layer formed by a polymer matrix and an ionic liquid on the surface of a core electrode with a nanopore network, the ionic liquid containing imidazole cations and bistrifluoromethanesulfonylimide anions, so that the two form a mechanical interlocking effect, the interface bonding strength is significantly enhanced, and the problem of interlayer sliding under repeated bending or stretching working conditions is solved. Meanwhile, the surface of the ion gel electrolyte layer is coated with a carbon nanotube network or a reduced graphene oxide network as an infrared emissivity regulating surface, the highly connected nanometer network provides sufficient active point positions for the electrochemical intercalation of ions, so that the infrared reflectivity is greatly improved, and dynamic reversible regulation of the infrared radiation characteristics is realized.

Description

Technical Field

[0001] This application relates to the field of infrared radiation modulation technology, specifically to a flexible fiber-shaped infrared emissivity modulation device and its fabrication method. Background Technology

[0002] With the continuous development of infrared detection and precision guidance technologies, the survivability of various targets under complex thermal backgrounds faces increasingly severe challenges. Traditional static low emissivity coatings, due to their fixed emissivity, cannot adapt to rapid changes in environmental thermal characteristics and also have inherent limitations in suppressing heat dissipation, which can lead to an increase in the target's physical temperature.

[0003] In recent years, significant progress has been made in dynamic infrared emissivity modulation technology. For example, in existing technologies, electrochromic fibers are prepared using a custom-designed equipment based on a slurry layer-by-layer deposition method to produce radiochromic fibers. This device uses nickel-plated copper wire as the core electrode, sequentially coating carbon nanotubes through a continuous coating process, and then spirally winding ultrafine metal wires as the outermost electrode to construct a coaxial core-shell structured fibrous infrared emissivity modulation device.

[0004] However, this technical solution still suffers from limitations such as a relatively limited emissivity control range, difficulty in meeting the requirements for high-fidelity thermal characteristic matching under complex thermal backgrounds, and a reliance on physical winding for interface bonding, which makes it prone to interface slippage under repeated bending or stretching conditions. This results in a slow response speed, falling short of real-time thermal camouflage requirements, and the long-term stability of the interface under mechanical deformation is not clearly demonstrated, leading to unsuccessful cycle life verification. Furthermore, its electrolyte encapsulation relies on physical coating, with the outermost layer providing only physical protection through helically wound metal wires, leaving the electrolyte layer vulnerable to long-term volatilization. Summary of the Invention

[0005] The purpose of this invention is to provide a flexible fibrous infrared emissivity modulation device and its preparation method, which simultaneously achieves high interfacial bonding strength and long-range uniform infrared modulation, effectively overcomes interlayer slippage and axial electrical attenuation, and ensures that the fiber maintains stable and reversible infrared emissivity modulation performance even under bending and meter-long lengths.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a flexible fiber-shaped infrared emissivity modulation device, comprising: The core electrode has a network of interconnected nanopores on its surface; An ion gel electrolyte layer is coated on the surface of the core electrode. The ion gel electrolyte layer is an ion gel layer formed by a polymer matrix and an ion liquid. The ion liquid contains imidazole cations and bis(trifluoromethanesulfonyl)imide anions. An infrared radiation modulation layer is coated on the surface of the ion gel electrolyte layer, wherein the infrared radiation modulation layer is a carbon nanotube network or a reduced graphene oxide network. The outer electrode is spirally wound around the surface of the infrared radiation modulation layer; The polymer matrix is ​​selected from one or more of thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide or polymethyl methacrylate; the imidazole cation is selected from one or more of 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation or 1-propyl-3-methylimidazolium cation.

[0007] Furthermore, the pore size of the nanopore network is in the range of 30nm-100nm.

[0008] Furthermore, the nanoporous network is formed by electrolytic acid etching of wires / conductive fibers.

[0009] Furthermore, the pitch of the spiral winding is 1mm to 3mm.

[0010] Furthermore, the core electrode is selected from one of metal fibers, carbon fibers, or conductive polymer fibers; the outer electrode is selected from one of metal wires, carbon fibers, or conductive polymer fibers; and the carbon nanotube network is a multi-walled carbon nanotube film, a single-walled carbon nanotube film, or a carbon nanotube array.

[0011] Furthermore, the device, under a ±4V drive voltage, exhibits an infrared emissivity modulation depth... Response time ≤ 3s.

[0012] Furthermore, the device is a fibrous device integrated into a fabric.

[0013] This application also provides a method for fabricating the above-mentioned flexible fiber-shaped infrared emissivity modulation device, comprising: S1: Surface treatment of the wire / conductive fiber to form a network of interconnected nanopores on its surface to obtain the core electrode; S2: Coating the surface of the core electrode with an ion gel precursor solution, and drying and curing it to form an ion gel electrolyte layer, wherein the ion gel electrolyte layer is an ion gel layer formed by a polymer matrix and an ion liquid; S3: Coat the surface of the ion gel electrolyte layer with a carbon nanotube network or a reduced graphene oxide network to form an infrared radiation modulation layer; S4: An external electrode is disposed on the surface of the infrared radiation modulation layer in a spiral winding manner.

[0014] Further, the preparation method of the ionic gel precursor solution includes: dissolving a polymer matrix and an ionic liquid in an organic solvent at a mass ratio of 1:1 to 1:4; wherein the polymer matrix is ​​selected from one or more of thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or polymethyl methacrylate; the ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, or 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; and the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, or tetrahydrofuran. Preferably, the mass ratio of the polymer matrix to the ionic liquid is 1:2.

[0015] The beneficial effects of the present invention include at least the following: The flexible fiber-like infrared emissivity modulation device of this application utilizes an ion gel electrolyte layer formed by a polymer matrix and an ion liquid, coated on the surface of a core electrode with a network of interconnected nanopores. The ion liquid contains imidazole cations and bis(trifluoromethanesulfonyl)imide anions, creating a "mechanical interlocking" effect that significantly enhances the interfacial bonding strength and solves the problem of interlayer slippage under repeated bending or stretching conditions. Simultaneously, by coating the surface of the ion gel electrolyte layer with a carbon nanotube network layer or a reduced graphene oxide network as the infrared emissivity modulation surface, the highly interconnected nanonetwork provides ample active sites for the electrochemical intercalation of ions. When a bias voltage is applied, the anions and cations in the ion gel undergo electrochemical intercalation into the carbon nanotube network layer or the reduced graphene oxide network under the drive of a radial electric field. This increases the carrier concentration, shifts the Fermi level, and excites plasmon resonance, thereby enhancing infrared reflectivity. According to Kirchhoff's thermal radiation law, the increase in reflectivity directly translates into a decrease in emissivity, thus achieving dynamic and reversible modulation of infrared radiation characteristics.

[0016] Furthermore, since the external electrode is arranged in a spiral winding manner on the surface of the infrared radiation modulation layer, this spiral current collector architecture transforms the long-range axial charge transport into short-range radial electrode polarization, eliminating the accumulation of axial impedance. This effectively overcomes the problem of long-range electrical attenuation in one-dimensional long fiber devices, enabling the fiber to maintain uniform infrared modulation performance even at meter-scale lengths.

[0017] This application also utilizes the strong hydrogen bonds and dipole-dipole non-covalent interactions between the polymer matrix and the ionic liquid to firmly anchor the ionic liquid within the three-dimensional polymer framework, forming a quasi-solid-state ionic gel. This ionic gel not only retains high ionic conductivity comparable to that of a pure liquid, but also... Furthermore, it fundamentally eliminates the risk of leakage and volatilization of liquid electrolytes under stress or long-term operation. Experiments have shown that after 2000 charge-discharge cycles, the infrared tuning performance of this device still retains 86.6%, fully demonstrating its excellent environmental adaptability and long-term service stability.

[0018] Therefore, the flexible fiber-shaped infrared emissivity modulation device of this application can simultaneously achieve high interfacial bonding strength and long-range uniform infrared modulation, effectively overcome interlayer slippage and axial electrical attenuation, and ensure that the fiber maintains stable and reversible infrared emissivity modulation performance even under bending and meter-scale lengths.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a coaxial core-shell structured fibrous infrared emissivity modulation device according to the present invention; Figure 2 This is a scanning electron microscope (SEM) image of the surface of the porous metal core obtained in step one of Example 1; Figure 3 This is a comparison of the maximum emissivity modulation depth of devices with different gel coating thicknesses; Figure 4 These are in-situ infrared thermal images of the fiber device prepared in Example 1 under different bias voltages; Figure 5 These are the response time curves of the fiber device prepared in Example 1 under different bias voltages; Figure 6 This is a graph showing the performance retention rate of the fiber device prepared in Example 1 after 2000 cycles; Figure 7 This is a graph showing the apparent temperature regulation capability of the fiber device prepared in Example 1 under different background temperatures; Figure 8 This is an image showing the adaptive thermal camouflage effect of the fiber device prepared in Example 1 in a human wearable scenario; Figure 9 These are the mid-infrared reflectance spectra of the fiber device prepared in Example 1 under different bias voltages; Figure 10 This is the curve showing the integral emissivity of the fiber device prepared in Example 1 as a function of bias voltage.

[0021] Figure labels: 1. Core electrode; 2. Ion gel electrolyte layer; 3. Carbon nanotube network layer; 4. External electrode. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Please see Figure 1 The flexible fibrous infrared emissivity modulation device of one embodiment of the present invention comprises, from the inside out, a core electrode, an ion gel electrolyte layer, an infrared radiation modulation layer, and an outer electrode. In one embodiment, the device can be a fibrous device integrated into a fabric. In practical applications, the morphology of the device can be similar to that of conventional textile fibers (cotton, polyester, nylon, etc.), and it can be blended with ordinary yarns using textile processes (such as weaving, knitting, embroidery, etc.) to form a smart electronic fabric. Compared with the prior art of attaching planar devices to the surface of clothing, the fibrous device integrated into the fabric does not compromise the breathability and wearing comfort of the fabric, solving the problem of the difficulty in integrating existing planar infrared modulation devices into clothing. Moreover, the fibrous device can be freely bent and stretched with human movement in the fabric, without rigid nodes or interface stress concentration problems. The device has an infrared emissivity modulation depth of ±4V driving voltage. Response time ≤ 3s.

[0025] The surface of the core electrode has a network of interconnected nanopores with pore sizes ranging from 30 nm to 100 nm. In an alternative embodiment, this interconnected nanopore network is formed by electrolytic acid etching of wires / conductive fibers, or by plasma etching, chemical deposition of nanoparticles, or other methods. The core electrode can be selected from metal fibers (such as copper wire, silver wire, or tin-plated copper wire), carbon fibers, or conductive polymer fibers.

[0026] An ionogel electrolyte layer is coated on the surface of the core electrode. The ionogel electrolyte layer is an ionogel layer formed by a polymer matrix and an ionic liquid. The ionic liquid contains imidazole cations and bis(trifluoromethanesulfonyl)imide anions. Specifically, the polymer matrix is ​​selected from one or more of thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or polymethyl methacrylate; the imidazole cation is selected from one or more of 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, or 1-propyl-3-methylimidazolium cation.

[0027] An infrared radiation modulation layer is coated on the surface of the ionogel electrolyte layer. This infrared radiation modulation layer is a carbon nanotube network or a reduced graphene oxide network. In specific applications, the carbon nanotube network can be a multi-walled carbon nanotube film, a single-walled carbon nanotube film, or a carbon nanotube array.

[0028] The external electrode is spirally wound around the surface of the carbon nanotube network layer. The external electrode can be one or more ultrafine wires or conductive fibers with a diameter of 30 μm to 80 μm. This electrode can be selected from metal wires, carbon fibers, or conductive polymer fibers. The spiral winding pitch is 1 mm to 3 mm. By setting the spiral range to 1 mm to 3 mm, a balance can be achieved between electric field uniformity and infrared radiation efficiency.

[0029] This device achieves a “mechanical interlocking” effect by coating the surface of the core electrode, which has a network of interconnected nanopores, with an ion gel electrolyte layer formed by a polymer matrix and an ion liquid. The ion liquid contains imidazole cations and bis(trifluoromethanesulfonyl)imide anions, which significantly enhances the interfacial bonding strength and solves the problem of interlayer slippage under repeated bending or stretching conditions.

[0030] Meanwhile, by coating the surface of the ion gel electrolyte layer with a carbon nanotube network layer or a reduced graphene oxide network as an infrared emissivity modulation surface, the highly interconnected nanonetwork provides ample active sites for the electrochemical intercalation of ions. When a bias voltage is applied, the anions and cations in the ion gel undergo electrochemical intercalation into the carbon nanotube network layer or the reduced graphene oxide network under the drive of the radial electric field. This can cause an increase in carrier concentration, a shift in the Fermi level, and excitation of plasmon resonance, thereby improving infrared reflectivity. According to Kirchhoff's thermal radiation law, the increase in reflectivity will directly translate into a decrease in emissivity, thus achieving dynamic and reversible control of infrared radiation characteristics.

[0031] Specifically, when a positive bias is applied, anions in the ionogel electrolyte layer migrate outward under the drive of the radial electric field and embed into the carbon nanotube network layer or reduced graphene oxide network for anion doping. When a negative bias is applied, cations are strongly driven to the outer layer, resulting in a deep cation intercalation reaction. With the injection of a large number of anions and cations, the carrier concentration inside the carbon nanotube network or reduced graphene oxide network increases sharply, and the Fermi level shifts dramatically, effectively suppressing the interband absorption of carbon materials in the mid-infrared band and simultaneously exciting a strong plasmon resonance effect. This change in microscopic energy bands directly leads to a significant increase in infrared reflectivity. According to Kirchhoff's thermal radiation law, for opaque materials, the sum of emissivity and reflectivity is always 1. The increase in reflectivity directly translates into a decrease in infrared emissivity, thereby achieving dynamic and reversible control of the infrared radiation characteristics of the device surface.

[0032] Taking a multi-walled carbon nanotube network as the infrared radiation modulation layer as an example, experimental results show that, driven by a working voltage of ±4V, the spectral emissivity of a 60μm thick device can be modulated from the initial high-emissivity state (0.80) to the low-emissivity state (0.32), with a maximum emissivity modulation depth. The emissivity reached 0.48, with response times of 1.9 s (forward bias) and 2.3 s (negative bias). After up to 2000 cycles of repeated charge-discharge and infrared modulation, the overall performance retention remained at an extremely high level (close to 86.6%). It is understandable that when a reduced graphene oxide network replaces the multi-walled carbon nanotube network, based on a similar electrochemical intercalation mechanism, the device can also achieve dynamic control of infrared emissivity. Specific performance parameters may vary due to differences in the microstructure of the materials, but all fall within the scope of protection covered by this invention.

[0033] Furthermore, because the external electrodes are spirally wound onto the surface of the infrared radiation modulation layer, this application utilizes a spiral current collector architecture to transform long-range axial charge transport into short-range radial electrode polarization, eliminating axial impedance accumulation. This effectively overcomes the long-range electrical attenuation problem in one-dimensional long fiber devices, allowing the fiber to maintain uniform infrared modulation performance even at meter-length lengths. Experimental results show that at a fiber length of 1 m, the attenuation rate of the end modulation depth is reduced from over 50% of that of traditional axial electrode structures to below 5%, significantly addressing the limitation of coaxial dynamic infrared radiation modulation fiber devices being unable to fabricate long-length devices due to length constraints.

[0034] Therefore, this flexible fiber-shaped infrared emissivity modulation device can simultaneously achieve high interfacial bonding strength and long-range uniform infrared modulation, effectively overcoming interlayer slippage and axial electrical attenuation, and ensuring that the fiber maintains stable and reversible infrared emissivity modulation performance even under bending and meter-long lengths.

[0035] When the device was used as a fabric, the test results showed that the temperature difference could be controlled up to 21°C under extreme heating conditions of 90°C. The actual wear test on the human body confirmed that the device can achieve rapid, bidirectional, high-fidelity thermal camouflage under complex high and low temperature conditions.

[0036] It should be noted that in this embodiment, an interconnected nanoporous network is formed on the surface of the core electrode through electrolytic acid etching, creating a mechanically interlocking structure between the core electrode and the ion gel electrolyte. This interlocking structure depends not only on the geometry of the pores but also on the volume shrinkage effect during the ion gel curing process, resulting in a tight physical fit between the gel material and the inner wall of the pores.

[0037] It should also be noted that during the research and development process of this application, the inventors discovered that in the field of flexible fibrous infrared control devices, the conventional technical approaches to solving the interfacial slippage problem between the core electrode and the electrolyte layer mainly include: increasing the winding density of the outer electrode and coating the surface of the core electrode with a flexible adhesive layer. The common feature of these methods is that they rely on macroscopic structures (such as winding and bonding) or the introduction of third-party adhesive materials to improve the interfacial bonding force. Furthermore, during the process of devising a solution, the literature reviewed revealed that those skilled in the art generally hold the following technical biases: the main function of nanopores formed on the surface of metal wires through electrolytic acid etching is to increase the specific surface area to enhance the density of electrochemical active sites or improve the adhesion between the coating and the substrate. However, it is not considered that these nanopores can form a strong mechanical interlock with the subsequently coated polymer-based ionogel to resist interfacial slippage under repeated bending / stretching conditions. This is because, although ionogels undergo volume shrinkage during curing, those skilled in the art generally consider this shrinkage effect to be "adverse," as it can easily lead to internal stress, cracking, or detachment from the substrate in the gel layer. Therefore, shrinkage is often suppressed by adjusting the solvent evaporation rate or adding plasticizers, rather than utilizing the shrinkage effect.

[0038] However, the inventors broke through existing knowledge and, through numerous experiments, discovered that when an electrolytic acid etching process is used to form a network of interconnected nanopores on the surface of the core electrode, and its surface is coated with a specific ion gel electrolyte layer, specifically, the core electrode in a specific ion gel precursor solution (such as thermoplastic polyurethane (TPU) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt solution) During the impregnation, lifting, and drying process using a 1:2 N,N-dimethylformamide (DMF) solution, the evaporation of the DMF solvent causes controlled shrinkage of the ionogel volume. Since the size of the nanopores is on the same order of magnitude as the radius of gyration of the ionogel molecular chains, the gel material is "pulled" deep into the pores during shrinkage, forming a three-dimensional mechanically interlocked structure after solidification. This structure not only prevents the gel layer from cracking but also increases the interfacial shear strength several times compared to conventional physically wound interfaces (example data shows that the device maintains structural integrity after 2000 bending / stretching cycles).

[0039] This application also provides a method for fabricating the above-mentioned flexible fiber-shaped infrared emissivity modulation device, comprising: S1: Surface treatment of the wire / conductive fiber to form a network of interconnected nanopores on its surface to obtain the core electrode. In specific applications, the core electrode can be selected from one of metal fiber, carbon fiber or conductive polymer fiber. S2: An ion gel precursor solution is coated on the surface of the core electrode and dried and cured to form an ion gel electrolyte layer. The ion gel electrolyte layer is an ion gel layer formed by a polymer matrix and an ion liquid. S3: A carbon nanotube network or a reduced graphene oxide network is coated onto the surface of the ionogel electrolyte layer to form an infrared radiation modulation layer. In specific applications, this carbon nanotube network can be a multi-walled carbon nanotube film, a single-walled carbon nanotube film, or a carbon nanotube array; S4: An external electrode is arranged on the surface of the infrared radiation modulation layer in a spiral winding manner. In specific applications, the external electrode can be selected from one of the following: metal wire, carbon fiber, or conductive polymer fiber.

[0040] In an alternative embodiment, in step S1, the surface treatment employs a constant current electrolysis method, using a wire / conductive fiber as the anode, and electrolytic etching is performed in a sulfuric acid electrolyte. Specifically, copper wire is used, and it is ultrasonically cleaned sequentially in acetone and ethanol to remove surface oil. Then, using sulfuric acid solution as the electrolyte, the pre-treated copper wire is used as the anode, and a stainless steel sheet (or platinum wire) as the cathode. A constant current electrolysis method is employed, and the micro-roughness of the copper wire surface is altered by controlling the electrolysis time to increase the specific surface area, thereby obtaining the core electrode. The pore size of the nanoporous network is controlled to be 30 nm to 100 nm by controlling the electrolysis time.

[0041] In an alternative embodiment, the core electrode is coated with an ion gel electrolyte layer by dip-coating. Specifically, the treated core electrode is used as a substrate, and an ion gel precursor solution is uniformly coated on its surface by dip-coating. After drying and curing, a dense solid ion gel layer is formed on the surface of the core electrode. The dipping speed can be 0.5 cm / min to 5 cm / min.

[0042] In one embodiment, the method for preparing the ionogel precursor solution includes: dissolving a polymer matrix and an ionic liquid in an organic solvent at a mass ratio of 1:1 to 1:4; wherein the polymer matrix is ​​selected from one or more of thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or polymethyl methacrylate; the ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, or 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; and the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, or tetrahydrofuran. Preferably, the thermoplastic polyurethane and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide are dissolved in N,N-dimethylformamide at a mass ratio of 1:2.

[0043] The preparation method described above will be illustrated with some specific examples below.

[0044] Example 1 The fabrication method of the coaxial core-shell structured fibrous infrared emissivity modulating device in this embodiment includes: S1. Core Electrode Preparation: Copper wire (200 μm in diameter) was ultrasonically cleaned in acetone and ethanol sequentially to remove surface oil. A constant current electrolysis method was used, with 15% sulfuric acid solution as the electrolyte. The pretreated metal fiber was used as the anode, and a stainless steel sheet as the cathode, at a current of 1 A / dm². 2 The metal fiber surface was treated at a current density of 30 s to construct an interconnected porous network structure with a pore size of approximately 50 nm. S2, Forming a solid ionogel layer: A solution of thermoplastic polyurethane (TPU) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt (…) A solid ionogel precursor solution was prepared by dissolving the copper wire core obtained in S1 in N,N-dimethylformamide (DMF) at a mass ratio of 1:2. The porous copper wire core obtained in S1 was then passed through a storage tank containing the solid ionogel precursor solution using an dip-pull process at a speed controlled at 8.8 mm / s. A 60 μm thick ionogel layer was uniformly coated onto the surface of the metal core. The core was then transferred to a vacuum drying oven and continuously dried at 60 °C for 48 h to allow the solvent to fully evaporate. Electrochemical impedance spectroscopy analysis showed that the radial mass transfer impedance of the ionogel layer was 634.6 Ω (≤700 Ω).

[0045] S3, Coated Carbon Nanotube Network Layer: A multi-walled carbon nanotube (MWCNT) film is wrapped around the surface of the dried ion gel layer using a winding process; S4. Forming an external electrode: A loop of ultrafine copper wire is wound around the surface of the carbon nanotube network layer with a fixed helical pitch (2 mm) as an external current collector.

[0046] Example 2: The difference between this embodiment and Embodiment 1 is that the diameter of the copper wire in step S1 is 200μm (the same as in Embodiment 1, this is just an example and can be adjusted in practice).

[0047] Example 3: The difference between this embodiment and Embodiment 1 is that the electrolytic etching current density in step S1 is 0.5-2 A / dm. 2 The etching time is 20-60 seconds.

[0048] Example 4: The difference between this embodiment and Embodiment 1 is that the average pore size of the porous metal core surface in step S1 is 30-100 nm.

[0049] Example 5: The difference between this embodiment and embodiment 1 is that the lifting speed in step S2 is 5-12 mm / s.

[0050] Example 6: The difference between this embodiment and Embodiment 1 is that the thickness of the solid ionogel layer in step S2 is 40-80 μm.

[0051] Example 7: The difference between this embodiment and Embodiment 1 is that the multi-walled carbon nanotube (MWCNT) film in step S3 is replaced with a reduced graphene oxide network (rGO).

[0052] Example 8: The difference between this embodiment and embodiment 1 is that the spiral current collector in step S4 can be replaced by a conductive filament.

[0053] Example 9: The difference between this embodiment and embodiment 1 is that: after the spiral current collector is wound in step S4, it is encapsulated on the outermost layer of the fiber device, and the encapsulation material is a polyolefin thermoplastic tube.

[0054] The following combination Figures 2 to 10 The performance test results of the device prepared in Example 1 are analyzed and explained.

[0055] Figure 2 This is a scanning electron microscope (SEM) image of the surface of the porous metal core obtained in step one of Example 1. Figure 2 (a), (b), (c), and (d) show the microstructure at different magnifications, with scale bars of 80 μm, 40 μm, 200 nm, and 50 nm, respectively, which respectively demonstrate the characteristics from micron-level pore structure to nano-level surface details. It can be seen that the copper wire surface is uniformly etched to form an extremely dense, highly interconnected porous network structure with a pore size of about 50 nm.

[0056] Figure 3 This is a comparison of the maximum emissivity modulation depth of the devices under different gel coating thicknesses. From Figure 3 It can be seen that when the gel thickness is 60 μm, the maximum emissivity modulation depth of the device is... The maximum modulation depth reaches an extreme value of 0.48; when the thickness is too thin (20μm, 40μm), the maximum modulation depth is only 0.42 and 0.45 respectively due to the limited supply of ion source; when the thickness is too thick (80μm, 100μm), the maximum modulation depth drops back to 0.45 and 0.4 due to the increased radial mass transfer resistance.

[0057] Figure 4 This is a two-dimensional infrared thermal imaging distribution map of the fiber device prepared in Example 1 under different bias voltages. From... Figure 4It can be observed that: in the initial state (0V), the device exhibits a bright yellow high-emissivity characteristic, with an apparent temperature of 36℃; when the voltage rises to 2V, the surface turns orange, and the temperature drops to 31.8℃; at 3V, it turns purple, and the temperature drops to 29.6℃; under the 4V extreme bias voltage, the entire plane completely transforms into a dark black low-emissivity characteristic, and the apparent temperature drops to 26.3℃. Throughout the entire control process, the thermal image color distribution under each voltage gradient is extremely uniform, and no electrical loss patches or control blind spots appear due to size enlargement.

[0058] Figure 5 These are the response time curves of the fiber device prepared in Example 1 under different bias voltages. From... Figure 5 It can be seen that under ±4V drive, the device response time is stable at 1.9s and 2.3s respectively, which is very fast.

[0059] Figure 6 This is a graph showing the performance retention of the fiber device prepared in Example 1 after 2000 cycles. Figure 6 It can be seen that after 2000 cycles of repeated charge-discharge and infrared modulation, the infrared tuning performance retention rate of the device remains at an extremely high level of close to 86.6%.

[0060] Figure 7 The graph shows the apparent temperature regulation capability of the fiber device prepared in Example 1 under different background temperatures. (a) is a curve showing the dynamic change of the apparent temperature of the device under different background temperatures, which intuitively presents the temperature response process of the device during the heating and cooling cycles. (c) is a statistical bar chart of the apparent temperature regulation span of the device, showing the maximum temperature regulation difference under different base temperatures. It can be seen that in a wide temperature range of 30℃ to 90℃, the apparent temperature regulation span of the device increases with the increase of the background temperature. Under the extreme high temperature background of 90℃, by applying the ultimate operating bias voltage, the maximum modulation difference of the apparent temperature reaches 21℃.

[0061] Figure 8These are adaptive thermal camouflage effect images of the fiber device prepared in Example 1 in a wearable human scenario. (a) is a visible light view, visually presenting the device's wearing position and appearance; (b) and (c) are infrared thermal imaging views, demonstrating the thermal camouflage effect of the device under different operating states. (b) shows the state without external voltage (0V), where the device maintains high infrared emissivity and an apparent temperature of approximately 36.2℃, naturally matching the high-temperature background (36.4℃). (c) shows the state with ±4V bias applied, where the device's infrared emissivity drops sharply, and the apparent temperature drops to approximately 28℃, achieving thermal camouflage against the low-temperature background (23.7℃). Therefore, it can be seen that under a high-temperature background, the device maintains a high infrared emissivity of approximately 0.8 in the initial 0V state, and its apparent temperature naturally matches the surrounding hot environment. Under a low-temperature cold background, by applying a ±4V operating bias, the infrared emissivity drops sharply, and the fabric's apparent temperature drops precipitously, rapidly transforming into a dark tone consistent with the cold background, successfully achieving bidirectional thermal camouflage.

[0062] Figure 9 The figures show the mid-infrared reflectance spectra of the fiber device prepared in Example 1 under different bias voltages. (a) shows the mid-infrared reflectance spectra of the device under different positive bias voltages, corresponding to the test results of applying positive voltages of 0V, 1V, 2V, 3V, and 4V; (b) shows the mid-infrared reflectance spectra of the device under different negative bias voltages, corresponding to the test results of applying negative voltages of 0V, -1V, -2V, -3V, and -4V. It can be seen that the spectral curve exhibits a highly regular dynamic response as the external driving voltage is applied. Whether the positive voltage or the absolute value of the negative voltage is gradually increased, the infrared reflectance curve of the device shows an overall and continuous upward trend. It can be clearly seen from the figures that when the bias voltage gradually approaches the limit value (e.g., reaching ±4V), the increase in reflectance of the device in the 8-14μm band is particularly dramatic and concentrated.

[0063] Figure 10 This is the curve showing the integral emissivity of the fiber device prepared in Example 1 as a function of bias voltage. From... Figure 10 It can be seen that the integrated emissivity reaches a peak of about 0.8 in the initial state of 0V; as the positive and negative bias voltages gradually increase, the integrated emissivity decreases continuously, reaching a minimum of 0.32 under the -4V extreme bias voltage, and a minimum of about 0.35 at 4V, demonstrating the device's ability to perform stepless, precise and continuous control of the surface thermal signal.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A flexible fiber-shaped infrared emissivity modulation device, characterized in that, include: The core electrode is formed by electrolytic acid etching of the wire / conductive fiber to create a network of interconnected nanopores on its surface, with the pore size of the nanopores ranging from 30 nm to 100 nm. An ion gel electrolyte layer is coated on the surface of the core electrode. The ion gel electrolyte layer is an ion gel layer formed by a polymer matrix and an ion liquid. The ion liquid contains imidazole cations and bis(trifluoromethanesulfonyl)imide anions. An infrared radiation modulation layer is coated on the surface of the ion gel electrolyte layer, wherein the infrared radiation modulation layer is a carbon nanotube network or a reduced graphene oxide network. The outer electrode is spirally wound around the surface of the infrared radiation modulation layer; The polymer matrix is ​​selected from one or more of thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or polymethyl methacrylate; the imidazole cation is selected from one or more of 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, or 1-propyl-3-methylimidazolium cation. During the curing process of the ionogel electrolyte layer, a volume shrinkage effect occurs. The gel material in the ionogel electrolyte layer is pulled into the nanoporous network during the shrinkage process, so that the gel material and the interior of the nanoporous network form a tight physical interlocking, forming a three-dimensional mechanical interlocking structure.

2. The flexible fiber-shaped infrared emissivity modulation device as described in claim 1, characterized in that, The pitch of the spiral winding is 1 mm to 3 mm.

3. The flexible fiber-shaped infrared emissivity modulation device as described in claim 1, characterized in that, The core electrode is selected from one of metal fiber, carbon fiber or conductive polymer fiber; the outer electrode is selected from one of metal wire, carbon fiber or conductive polymer fiber; when the infrared radiation modulation layer is a carbon nanotube network, the carbon nanotube network is a multi-walled carbon nanotube film, a single-walled carbon nanotube film or a carbon nanotube array.

4. The flexible fiber-shaped infrared emissivity modulation device as described in claim 1, characterized in that, The device, under a ±4V drive voltage, has an infrared emissivity modulation depth. Response time ≤ 3s.

5. The flexible fiber-shaped infrared emissivity modulation device as described in claim 1, characterized in that, The device is a fibrous device integrated into a fabric.

6. A method for fabricating a flexible fiber-shaped infrared emissivity modulating device as described in any one of claims 1-5, characterized in that, The preparation method includes: S1: Surface treatment of the wire / conductive fiber to form a network of interconnected nanopores on its surface to obtain the core electrode; S2: Coating the surface of the core electrode with an ion gel precursor solution, and drying and curing it to form an ion gel electrolyte layer, wherein the ion gel electrolyte layer is an ion gel layer formed by a polymer matrix and an ion liquid; S3: Coat the surface of the ion gel electrolyte layer with a carbon nanotube network or a reduced graphene oxide network to form an infrared radiation modulation layer; S4: An external electrode is disposed on the surface of the infrared radiation modulation layer in a spiral winding manner.

7. The preparation method according to claim 6, characterized in that, The method for preparing the ion gel precursor solution includes: dissolving a polymer matrix and an ionic liquid in an organic solvent at a mass ratio of 1:1 to 1:4; wherein the polymer matrix is ​​selected from one or more of thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or polymethyl methacrylate; the ionic liquid is selected from one or more of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, or 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; and the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, or tetrahydrofuran.

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