Gel-based wave-absorbing material as well as preparation method and application thereof

Abstract

The invention relates to a gel-based wave-absorbing material as well as a preparation method and application thereof. The gel-based wave-absorbing material comprises a polymer serving as a framework, hydrophobic ionic liquid, a photoinitiator and a cross-linking agent, the polymer serving as the framework is formed by polymerizing monomers, and the monomers are hydrophilic monomers and / or hydrophobic monomers; the gel-based wave-absorbing material is a hydrophobic, transparent, stretchable and tough ionic gel; the ionic gel is prepared from hydrophobic ionic liquid, a hydrophobic monomer, a hydrophilic monomer, a cross-linking agent and a photoinitiator through photocuring and carbonization. The gel-based wave-absorbing material can be used as an electromagnetic wave-absorbing material, is applied to the sensing field and is used for absorbing electromagnetic waves in X and Ku wave bands.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic wave absorbing materials, and specifically relates to a gel-based absorbing material and a preparation method and application thereof. Background Art

[0002] With the breakthrough of wireless communication technology, wireless connection devices such as augmented reality (AR), artificial intelligence (AI), wearable electronic devices, flexible electronic screens and radio frequency identification (RFID) have become an important part of the current and future society. However, in a complex electromagnetic environment, these precision devices will inevitably be interfered by electromagnetic waves. In order to ensure the normal operation of these devices, electromagnetic wave (EMW) absorbing materials are indispensable. Electromagnetic wave absorbing materials are usually required to have: (i) a wide effective absorption bandwidth (EAB); (ii) transparency, durability, flexibility and simple manufacturing process.

[0003] Traditional electromagnetic wave absorbing materials include: carbon-based absorbing materials (such as graphene, graphite, carbon black, carbon fiber, carbon nanotubes), iron-based absorbing materials (such as ferrite, magnetic iron nanomaterials), and ceramic-based absorbing materials (such as silicon carbide).

[0004] For example, patent CN112521657B provides an electromagnetic wave absorbing material and a preparation method thereof, the method comprising: preparing an electromagnetic wave absorbing material (Y2Fe17-xSix) quick-setting sheet by quick-setting technology using yttrium, iron and silicon in proportion under argon environment protection; the electromagnetic wave absorbing material provided by the invention can be compounded with different electrically insulating polymer materials to obtain different electromagnetic wave absorbing materials-organic composite materials, and the thickness of the Y2Fe17-xSix electromagnetic wave absorbing material-organic composite material can be adjusted to absorb electromagnetic waves of different bands, and the absorption rate of electromagnetic waves is greater than 90%; however, the ferrite absorbing material provided by the invention lacks high optical transparency and flexibility / stretchability, and the raw material involved, the rare earth metal yttrium, is relatively expensive and relatively difficult to obtain.

[0005] For example, patent CN107072128B provides a broadband absorbing material based on a three-dimensional porous structure of polyaniline graphene. The absorbing material has a significant absorption effect on incident electromagnetic waves in the 4-18 GHz band, and the density does not exceed 25 mg / cm 3, thickness and area are controllable. The density of the electromagnetic wave absorbing material of the present invention is much lower than that of carbonyl iron, carbon black, carbon fiber and other absorbing materials, and the total mass per cubic meter does not exceed 25g; for microwaves in the frequency range of 6 to 18GHz, the reflectivity of the electromagnetic wave absorbing material is below -10dB; the absorbing material has excellent performance, but it also lacks high optical transparency and flexibility / stretchability, and the preparation process involves inert gas, high-temperature calcination and other operations, which is relatively complicated.

[0006] In summary, these traditional electromagnetic wave absorbing materials lack high optical transparency and flexibility / stretchability, and their preparation methods are relatively complicated, which limits their application in precision instruments such as optical and flexible devices. Summary of the invention

[0007] In view of the shortcomings of the conventional electromagnetic wave absorbing materials in the prior art, such as the lack of high optical transparency and flexibility / stretchability and the relatively complicated preparation method, the present invention aims to provide a gel-based absorbing material and its preparation method and application, wherein the gel-based absorbing material is a hydrophobic, transparent, stretchable, and tough ion gel. The transparent, stretchable, and tough gel-based absorbing material provided by the present invention has high visible light transparency and excellent stretchable stability, has good electromagnetic wave absorption performance, and can be used as an electromagnetic wave absorbing material.

[0008] There are currently few absorbing materials that are ultra-transparent, highly stretchable, highly environmentally adaptable, durable, and conductive. Therefore, this application has developed a new type of ion gel with a phase-separated ternary polymer network. In addition to ultra-transparency, high stretchability, and durability, the absorbing material provided by this application also integrates other basic properties of ideal electromagnetic wave absorbing materials, including mechanical robustness, hydrophobicity, skin-like Young's modulus, fatigue resistance, puncture resistance, and ice resistance.

[0009] Typically, in ion gels, ionic liquids are used as both dispersion media and conductive ions. However, while increasing the content of ionic liquids can improve conductivity, it also weakens the synergistic bonding between solvated chains, resulting in reduced mechanical properties of ion gels. Here, the present application uses the phase separation principle to prepare a phase-separated ion gel. Phase separation or random copolymerization occurs in a single curing step, producing an isotropic ion gel that forms an in-situ phase domain. During the copolymerization process, a polymer-rich phase is formed, which is tightly bound by hydrogen bonds to improve mechanical strength, while the solvent-rich phase (ion conductive phase) remains intact, resulting in a large strain. More importantly, since no other conductive fillers are added, the ionic conductivity and the desired transparency can be fine-tuned by adjusting the proportion of the rich aggregate phase. Unlike traditional electronic conductive loss absorbers, ion gels rely on ionic conduction. Suitable ionic conductivity can enhance the conductive loss of ion gels and achieve ideal impedance matching.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] In a first aspect of the present invention, a gel-based absorbing material is provided, the gel-based absorbing material comprising: a polymer as a skeleton, a hydrophobic ionic liquid, a photoinitiator and a cross-linking agent; the polymer as the skeleton is polymerized by monomers, and the monomers are hydrophilic monomers and / or hydrophobic monomers;

[0012] The gel-based wave-absorbing material is a hydrophobic, transparent, stretchable and tough ion gel; the ion gel is obtained by photocuring and carbonizing a hydrophobic ionic liquid, a hydrophobic monomer, a hydrophilic monomer, a crosslinking agent and a photoinitiator.

[0013] Further, the hydrophobic ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium any one or more combinations of imidazolide trifluoroacetate, N-butyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide, N-hexylpyridinium hexafluorophosphate, 1,2-dimethyl-3-hydroxyethylimidazolide bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolide hexafluorophosphate, -butyl-1-methylpyrrolidine trifluoromethanesulfonate, 1,3-dimethylimidazolide hexafluorophosphate, 1-butyl-3-methylimidazolide p-toluenesulfonate, 1-butyl-3-methylimidazolide bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolide hexafluorophosphate or N-methyl-N-butylpyrrolidine bis(trifluoromethanesulfonyl)imide.

[0014] Further, the hydrophilic monomer is any one or more combinations of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, acrylamide, 2-hydroxyethyl acrylate, methacrylate, n-butyl acrylate, N-isopropylacrylamide, N,N-dimethylacrylamide, and a polymer of methacrylamide monomers;

[0015] Furthermore, the hydrophobic monomer is any one or more of hexafluorobutyl acrylate, trifluoroethyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate or 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate.

[0016] Furthermore, the cross-linking agent is any one of poly(ethylene glycol) diacrylate and N,N-methylenebisacrylamide.

[0017] Furthermore, the photoinitiator is any one of 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone.

[0018] The second aspect of the present invention provides a method for preparing the above-mentioned gel-based absorbing material, comprising the following steps:

[0019] S1. Prepare a hydrophilic monomer solution, referred to as dispersion I; prepare a hydrophobic monomer solution, referred to as dispersion II; mix dispersion I and dispersion II to obtain a mixed solution;

[0020] S2. Prepare a mixed solution containing a hydrophobic ionic liquid, a crosslinking agent and a photoinitiator, referred to as dispersion III; the dispersion III is added to the mixed solution prepared in step S1, and stirred to obtain a mixed solution;

[0021] S3. The mixed solution obtained in S2 is exposed to ultraviolet light, and a target product is obtained through a one-step photocuring and carbonization, namely, the gel-based absorbing material.

[0022] Furthermore, in step S1, the mass percentage of the hydrophilic monomer in the final mixed solution is 1-40wt%; the mass percentage of the hydrophobic monomer in the final mixed solution is 1-40wt%; the mass ratio between the hydrophilic monomer and the hydrophobic monomer is (0.1-0.5):1;

[0023] In some preferred embodiments of the present application, the mass percentage of the hydrophilic monomer is 1wt%, 2wt%, 3wt%, 3.4wt%, 4wt%, 4.6wt%, 5wt%, 5.5wt%, 6wt%, 6.3wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.2wt%, 10wt%, 12wt%, 12.5wt%, 15wt%, 17wt%, 19wt%, 20wt%, 20.2wt%, 22wt%, 23.6wt%, 25wt%, 28wt%, 30.6wt%, 32wt%, 35wt%, 36.6wt%, 38wt%, 38.9wt% or 39.5wt%, and specific point values ​​between the above point values.

[0024] In some preferred embodiments of the present application, the mass percentage of the hydrophobic monomer is 1wt%, 2wt%, 3wt%, 3.4wt%, 4wt%, 4.6wt%, 5wt%, 5.5wt%, 6wt%, 6.3wt%, 7wt%, 7.5wt%, 8wt%, 8.2wt%, 10wt%, 12wt%, 12.5wt%, 15wt%, 17wt%, 19wt%, 20wt%, 20.2wt%, 21.83wt%, 22wt%, 23.6wt%, 25wt%, 28wt%, 30.6wt%, 32wt%, 35wt%, 36.6wt%, 38wt%, 38.9wt% or 39.5wt%, and specific point values ​​between the above point values.

[0025] In some preferred embodiments of the present application, the hydrophilic monomer is a combination of one or more of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-hydroxypropyl acrylate and / or acrylamide; the hydrophobic monomer is selected from a combination of one or more of hexafluorobutyl acrylate, trifluoroethyl methacrylate, and 2,2,3,4,4,4-hexafluorobutyl methacrylate.

[0026] In some specific embodiments of the present application, the hydrophilic monomer is selected from acrylic acid and acrylamide, and the addition ratio between the two is 1:5 to 3:1, accounting for 6.5 wt % of the total mass of the final mixed solution.

[0027] In some specific embodiments of the present application, the hydrophobic monomer is selected from hexafluorobutyl acrylate.

[0028] Further, in step S2, the mass percentage of the hydrophobic ionic liquid in the final mixed solution is 50-80wt%; the mass percentage of the cross-linking agent in the final mixed solution is 0.1-0.3wt%; the mass percentage of the photoinitiator in the final mixed solution is 0.04-0.07wt%;

[0029] In some preferred embodiments of the present application, the mass percentage of the hydrophobic ionic liquid is 50wt%, 50.5wt%, 51wt%, 51.6wt%, 52.3wt%, 54wt%, 54.6wt%, 55wt%, 55.3wt%, 56.5wt%, 57.6wt%, 58wt%, 58.4wt%, 59.6wt%, 60wt%, 60.1wt%, 63wt%, 64.9wt%, 65wt%, 66wt%, 67.5wt%, 68wt%, 69.9wt%, 70wt%, 70.2wt%, 71.4wt%, 72wt%, 73.5wt%, 74.2wt%, 75.6wt%, 76.3wt%, 77.6wt%, 78wt%, 78.9wt% or 79.9wt% and specific point values ​​between the above point values.

[0030] In some preferred embodiments of the present application, the mass percentage of the cross-linking agent is 0.1wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt%, 0.16wt%, 0.17wt%, 0.18wt%, 0.19wt%, 0.2wt%, 0.21wt%, 0.22wt%, 0.23wt%, 0.24wt%, 0.25wt%, 0.26wt%, 0.27wt%, 0.28wt%, 0.29wt% or 0.3wt% and specific point values ​​between the above point values.

[0031] In some preferred embodiments of the present application, the mass percentage of the photoinitiator is 0.04wt%, 0.041wt%, 0.042wt%, 0.043wt%, 0.044wt%, 0.046wt%, 0.048wt%, 0.049wt%, 0.05wt%, 0.052wt%, 0.053wt%, 0.054wt%, 0.056wt%, 0.057wt%, 0.058wt%, 0.059wt%, 0.06wt%, 0.061wt%, 0.062wt%, 0.063wt%, 0.064wt%, 0.065wt%, 0.066wt%, 0.067wt%, 0.068wt%, 0.069wt% or 0.07wt% and specific point values ​​between the above point values.

[0032] In some preferred embodiments of the present application, the hydrophobic ionic liquid is selected from any one of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide or 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

[0033] In some preferred embodiments of the present application, the cross-linking agent is selected from any one of poly(ethylene glycol) diacrylate and N,N-methylenebisacrylamide.

[0034] In some preferred embodiments of the present application, the photoinitiator is any one of 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone.

[0035] Furthermore, in step S3, the duration of ultraviolet light irradiation is 10 to 120 minutes; the wavelength of ultraviolet light is 340 to 380 nm, preferably 360 nm.

[0036] In a third aspect of the present invention, the present invention provides application of the gel-based absorbing material as an electromagnetic wave absorbing material in the field of sensing.

[0037] Furthermore, the gel-based absorbing material has the characteristics of being hydrophobic, transparent, stretchable and tough, and can be used as an electromagnetic wave absorbing material in the X and Ku bands in practical applications.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The hydrophobic, transparent, stretchable, and tough ion gel provided by the present invention utilizes the different solubility of hydrophilic and hydrophobic monomers in hydrophobic ionic liquids as the principle to produce phase separation, and has good conductivity, stretchability, and mechanical strength. By adjusting the ratio of hydrophilic and hydrophobic monomers, the mechanical properties, electrical conductivity, and transparency of the material can be effectively changed, and the ion gel formed under different ratio conditions can be used to regulate the electrical conductivity to regulate electromagnetic parameters and optimize impedance matching. The conductivity loss from ion conduction and the polarization loss from hydrogen bonding and ion-dipole polarization can make full use of different dissipation mechanisms to obtain better absorption performance.

[0040] (2) The hydrophobic, transparent, stretchable, and tough ion gel provided by the present invention is obtained by a one-step photocuring method. The parameters in the preparation process are controllable, the process is simple, the cost is low, and it is suitable for industrial production. By adjusting the parameters in the preparation process, the transparency, conductivity, mechanical properties, electromagnetic parameters, and wave absorption properties of the hydrophobic, transparent, stretchable, and tough ion gel can be easily adjusted. This is conducive to the preparation of wave absorbing materials that adapt to different environments and broaden the use scenarios of the materials.

[0041] (3) In addition to ultra-transparency, high stretchability and durability, the absorbent material provided by the present application also integrates other basic properties of ideal electromagnetic wave absorbing materials, including mechanical robustness, hydrophobicity, and puncture resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1Optical image of the hydrophobic, transparent, stretchable, tough ion gel provided in Example 1;

[0043] Figure 2 Atomic force microscopy (AFM) image of the hydrophobic, transparent, stretchable, tough ion gel provided in Example 1;

[0044] Figure 3 The transparency curve of the hydrophobic, transparent, stretchable, tough ion gel provided in Example 2;

[0045] Figure 4 The mechanical properties of the hydrophobic, transparent, stretchable, and tough ion gel provided in Example 3;

[0046] Figure 5 The skin-like tissue modulus data provided in Example 5;

[0047] Figure 6 Fatigue resistance provided by Example 6;

[0048] Figure 7 The hydrophobicity picture of the hydrophobic, transparent, stretchable, tough ion gel provided in Example 6;

[0049] Figure 8 The hydrophobic, transparent, stretchable, tough ion gel puncture resistance picture provided in Example 7;

[0050] Fig. 9 This is the anti-icing picture of Example 8;

[0051] Fig.10 It is a reflection loss diagram of the hydrophobic, transparent, stretchable, and tough ion gel of Example 1-2 of the present invention when absorbing waves; wherein a1 and a2 are the 3D reflection loss diagram and the 2D reflection loss projection mapping diagram of Example 1; b1 and b2 are the 3D reflection loss diagram and the 2D reflection loss projection mapping diagram of Example 2;

[0052] Fig.11 It is a reflection loss diagram of the hydrophobic, transparent, stretchable, and tough ion gel of Examples 6-8 of the present invention when absorbing waves; wherein a1 and a2 are the 3D reflection loss diagram and the 2D reflection loss projection mapping diagram of Example 6;

[0053] b1 and b2 are the 3D reflection loss diagram and the 2D reflection loss projection mapping diagram of Example 7; c1 and c2 are the 3D reflection loss diagram and the 2D reflection loss projection mapping diagram of Example 8;

[0054] Fig.12 The invention discloses the transmission and absorption of different waves by the gel-based wave absorbing material. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific embodiments. It should be pointed out that the following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be pointed out that for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention. It should be pointed out that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0056] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0057] Examples 1 to 3

[0058] A hydrophobic, transparent, stretchable, tough ion gel, prepared by the following steps:

[0059] (1) The hydrophilic monomer used is acrylic acid, which is referred to as dispersion I; the hydrophobic monomer used is hexafluorobutyl acrylate, which is referred to as dispersion II; dispersion I and dispersion II are mixed evenly to obtain a mixed solution (specific mixing ratio is shown in Table 1), ensuring that the mixed solution accounts for 29.7 wt% of the total mass;

[0060] (2) mixing the above-mentioned mixed solution with a hydrophobic ionic liquid, a crosslinking agent and a photoinitiator, and stirring to obtain a uniformly dispersed mixed solution; the hydrophobic ionic liquid used is 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide, the crosslinking agent is poly(ethylene glycol) diacrylate, and the photoinitiator is 1-hydroxycyclohexyl phenyl ketone; ensuring that the hydrophobic ionic liquid accounts for 70wt% of the total mass of the final mixed solution, the crosslinking agent accounts for 0.25wt% of the total mass of the final mixed solution, and the photoinitiator accounts for 0.05wt% of the total mass of the final mixed solution;

[0061] (3) The mixed solution obtained in step (2) is irradiated under a 360 nm ultraviolet lamp for 30 min to obtain a hydrophobic, transparent, stretchable, and tough ion gel.

[0062] Table 1 Mixing mass ratio of dispersions I and II

[0063] Mixing ratio of dispersion I and dispersion II Example 1 0.1:1 Example 2 0.3:1 Example 3 0.5:1

[0064] Combining the above preparation steps and Table 1, it can be seen that in the hydrophobic, transparent, stretchable and tough ion gels provided in Examples 1 to 3, by adjusting the mass ratio of dispersion I to dispersion II, ion gels with different transparencies and tensile strengths can be obtained, thereby adjusting the electromagnetic wave absorption performance of the material.

[0065] Figure 1 The optical picture of the hydrophobic, transparent, stretchable and tough ion gel provided in Example 1, from which it can be seen that the ion gel has high transparency;

[0066] Figure 2 The atomic force microscope (AFM) image of the hydrophobic, transparent, stretchable, and tough ion gel provided in Example 1 shows that there is obvious phase separation behavior inside the ion gel;

[0067] Figure 3 The transparency curve of the hydrophobic, transparent, stretchable, and tough ion gel provided in Example 2. As can be seen from the figure, the ion gel has high optical transparency;

[0068] Figure 4 The mechanical properties of the hydrophobic, transparent, stretchable and tough ion gel provided in Example 3. As can be seen from the figure, the fracture stress of the ion gel reaches 0.4 MPa when the strain is 600%, indicating that the mechanical properties of the ion gel are good.

[0069] Embodiments 4 to 9

[0070] A hydrophobic, transparent, stretchable, tough ion gel, prepared by the following steps:

[0071] (1) The hydrophilic monomers used are acrylic acid and acrylamide, and the hydrophobic monomer is hexafluorobutyl acrylate; the total mass percentage of the hydrophilic monomers (hydrophilic monomer mass I: acrylic acid and hydrophilic monomer mass II: acrylamide) is kept constant at 6.5wt%. The specific mixing ratio of the hydrophilic monomer mass I and the hydrophilic monomer mass II is shown in Table 2; the hydrophilic monomer solution is recorded as dispersion I;

[0072] Table 2 Mixing mass ratio of hydrophilic monomer I and hydrophilic monomer II

[0073] Mixing ratio of hydrophilic monomer I and hydrophilic monomer II Example 4 1:5 Example 5 1:3 Example 6 1:2 Example 7 1:1 Example 8 2:1 Example 9 3:1

[0074] (2) preparing a hydrophobic monomer solution, wherein the mass fraction of the hydrophobic monomer is 21.83 wt %, and is recorded as dispersion II;

[0075] The hydrophilic monomer solution (dispersion liquid I) prepared in step (1) and the hydrophobic monomer solution (dispersion liquid II) prepared in step (2) are mixed, and stirred to disperse them uniformly to obtain a mixed solution;

[0076] (3) preparing a solution containing a hydrophobic ionic liquid, a crosslinking agent, and a photoinitiator, wherein the hydrophobic ionic liquid in the solution is: 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide, with a mass fraction of 71.4 wt %; the crosslinking agent is: poly(ethylene glycol) diacrylate, with a mass fraction of 0.2 wt %; and the photoinitiator is: 1-hydroxycyclohexyl phenyl ketone, with a mass fraction of 0.07 wt %; the solution is recorded as dispersion III;

[0077] (4) adding the dispersion III prepared in step (3) to the mixed solution prepared in step (2), and continuing to stir and disperse evenly to obtain a mixed solution;

[0078] (5) irradiating the mixed solution obtained in step (4) under a 360 nm ultraviolet lamp for 60 min to obtain a hydrophobic, transparent, stretchable, and tough ion gel;

[0079] The mixing ratio of hydrophilic monomers I and II in step (1) was adjusted as shown in Table 2 to obtain Examples 4 to 9, while the mass fractions of the remaining steps (2) and (3) and the mixing ratio in step (4) remained unchanged.

[0080] Combining the above preparation steps and Table 2, it can be seen that in the hydrophobic, transparent, stretchable and tough ion gels provided by Examples 4 to 9, by adjusting the mass ratio of hydrophilic monomer I to hydrophilic monomer liquid II, hydrophobic, transparent, stretchable and tough ion gels with different transparencies and conductivity can be obtained, thereby adjusting the electromagnetic wave absorption performance of the material.

[0081] Figure 5 The skin-like tissue modulus diagram of the hydrophobic, transparent, stretchable, and tough ion gel provided in Example 5 shows that the human skin tissue modulus is generally less than 2 MPa, while the ion gel tissue modulus prepared in the present application is less than this value, indicating that it has skin-like tissue properties.

[0082] Figure 6 The fatigue resistance graph of the hydrophobic, transparent, stretchable, and tough ion gel provided in Example 6 shows that after 200 stretching cycles, its mechanical properties remain stable, indicating that it has excellent fatigue resistance.

[0083] Figure 7 The hydrophobicity picture of the hydrophobic, transparent, stretchable and tough ion gel provided in Example 6 shows that the contact angle of the material is 115°, indicating that the hydrophobicity of the ion gel is good.

[0084] Figure 8 The hydrophobic, transparent, stretchable, and tough ion gel anti-puncture picture provided in Example 7 shows that the gel is extended and stretched instead of broken when confronted with a sharp object, indicating that the ion gel has puncture resistance.

[0085] Fig. 9 The hydrophobic, transparent, stretchable, tough ion gel anti-icing picture provided in Example 8 shows that when water passes through the gel on the -20°C surface, it can slide down quickly instead of freezing, indicating that it has certain anti-icing properties.

[0086] Fig.10 The diagram is a reflection loss diagram of the hydrophobic, transparent, stretchable and tough ion gel of Examples 1 to 2 of the present invention when absorbing waves; wherein a is the 2D reflection loss projection mapping diagram of Example 1; b is the 2D reflection loss projection mapping diagram of Example 2. It can be seen from the diagram that the ion gel can cover the entire X-band and has good electromagnetic wave absorption performance.

[0087] Fig.11 The reflection loss diagrams of hydrophobic, transparent, stretchable and tough ion gels of Examples 4 to 6 of the present invention when absorbing waves; wherein a is the 2D reflection loss projection mapping diagram of Example 4; b is the 2D reflection loss projection mapping diagram of Example 5; c is the 2D reflection loss projection mapping diagram of Example 6. It can be seen from the diagram that Example 4 has better absorbing performance, and the bandwidth can reach 7.85GHz. The ion gel has electromagnetic wave absorption performance.

[0088] In summary, the gel-based absorbing material provided in the present application has the characteristics of being hydrophobic, transparent, stretchable, and tough, and can absorb electromagnetic waves EMW well, while other visible light can be fully transmitted ( Fig.12 ).

[0089] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A gel-based absorbing material, characterized in that: The gel-based wave-absorbing material is prepared by photocuring and carbonizing a polymer, a hydrophobic ionic liquid, a photoinitiator and a cross-linking agent; the polymer serves as a skeleton and is polymerized from a hydrophilic monomer and a hydrophobic monomer.

2. A gel-based absorbing material according to claim 1, characterized in that: The hydrophobic ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium trifluorophosphate, A combination of any one or more of fluoroacetate, N-butyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide, N-hexylpyridinium hexafluorophosphate, 1,2-dimethyl-3-hydroxyethylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, -butyl-1-methylpyrrolidine trifluoromethanesulfonate, 1,3-dimethylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium p-toluenesulfonate, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate or N-methyl-N-butylpyrrolidine bis(trifluoromethanesulfonyl)imide.

3. The gel-based absorbing material according to claim 1, characterized in that: The hydrophilic monomer is any one or more of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, acrylamide, 2-hydroxyethyl acrylate, methacrylate, n-butyl acrylate, N-isopropylacrylamide, N,N-dimethylacrylamide or a combination of methacrylamide monomers.

4. The gel-based absorbing material according to claim 1, characterized in that: The hydrophobic monomer is any one or more of hexafluorobutyl acrylate, trifluoroethyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate or 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate.

5. The gel-based absorbing material according to claim 1, characterized in that: The cross-linking agent is any one of poly(ethylene glycol) diacrylate or N,N-methylenebisacrylamide.

6. The gel-based absorbing material according to claim 1, characterized in that: The photoinitiator is any one of 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone.

7. The method for preparing a gel-based microwave absorbing material according to claim 1, characterized in that: The steps include: S1. Prepare a hydrophilic monomer solution, referred to as dispersion I; prepare a hydrophobic monomer solution, referred to as dispersion II; mix dispersion I and dispersion II to obtain a mixed solution; S2. Prepare a mixed solution containing a hydrophobic ionic liquid, a crosslinking agent and a photoinitiator, referred to as dispersion III; the dispersion III is added to the mixed solution prepared in step S1, and stirred to obtain a mixed solution; S3. The mixed solution obtained in S2 is exposed to ultraviolet light, and a target product is obtained through a one-step photocuring and carbonization, namely, the gel-based absorbing material.

8. The method for preparing a gel-based absorbing material according to claim 7, characterized in that: In step S1, the mass percentage of the hydrophilic monomer in the final mixed solution is 1-40wt%; the mass percentage of the hydrophobic monomer in the final mixed solution is 1-40wt%; the mass ratio between the hydrophobic monomer and the hydrophilic monomer is 1:(0.1-0.5); In step S2, the mass percentage of the hydrophobic ionic liquid in the final mixed solution is 50-80wt%; the mass percentage of the cross-linking agent in the final mixed solution is 0.1-0.3wt%; the mass percentage of the photoinitiator in the final mixed solution is 0.04-0.07wt%; The duration of ultraviolet light irradiation in step S3 is 10 to 120 minutes; the wavelength of ultraviolet light is 340 to 380 nm.

9. The use of a gel-based absorbing material as claimed in claim 1, characterized in that: The gel-based absorbing material is used as an electromagnetic wave absorbing material in the field of electromagnetic protection.

10. The use of a gel-based absorbing material according to claim 9, characterized in that: The gel-based absorbing material is used as an electromagnetic wave absorbing material in the X and Ku bands.

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