Lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric and preparation method thereof

Abstract

The present invention relates to the technical field of wearable electromagnetic wave absorbing fabrics, and in particular to a lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric and a preparation method thereof. The super-hydrophobic absorbing fabric is formed by constructing an rGO / LDH / PPy layer on an aramid non-woven fabric by a hydrothermal method and in-situ growth to form a multi-dimensional heterogeneous structure, and then being modified with a low surface energy material modification layer. The super-hydrophobic absorbing fabric has excellent electromagnetic wave absorption performance and super-hydrophobic and self-cleaning performance, and has good stability. At the same time, it has heat insulation and flame retardant properties, as well as good lightness and flexibility, and can be bent and twisted at will. In future applications, whether in terms of its own lightness and flexibility or in terms of resistance to harsh environments and safety in use, it has very broad prospects.

Description

Technical Field

[0001] The invention relates to the technical field of wearable electromagnetic wave absorbing fabrics, in particular to a lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology and its wide application in the military field, battlefield military reconnaissance technology has achieved high-tech. Researchers have designed electromagnetic wave absorbing materials with various structures, such as powders, films and aerogels. Although these materials have made certain progress in the field of electromagnetic wave absorption, there are still some inevitable shortcomings, such as: high density, low yield, poor shape retention, poor flexibility and so on. Fortunately, electromagnetic wave absorbing materials with fabric structures can easily solve the above problems because of their unique integrated molding structure and inherent flexibility and lightness. People obtain electromagnetic wave absorbing fabrics by coating or modifying the surface of the fabric.

[0003] CN108951192A discloses a magnetic absorbing fabric and its preparation method and application. First, the magnetic metal ions are uniformly dispersed in the ionic waterborne polyurethane WPU by electrostatic attraction, and magnetic metal particles are generated in situ under hydrothermal conditions to obtain a magnetic WPU absorbing coating; then the coating is grafted on the surface of the thiol-modified textile by a thiol-ene click reaction. The invention solves the problem that the absorber is easy to agglomerate in the binder, and is beneficial to improving the absorbing performance of the absorbing fabric; then the thiol-ene click reaction is used to increase the bonding force between the absorbing layer and the fabric, so that it has practical wearability; the prepared magnetic absorbing fabric has high absorbing performance and good impedance matching, which can meet the development requirements of radar stealth materials.

[0004] Zhang et al. constructed an integrated impedance gradient composite fabric on a PET spacer fabric matrix, in which MXene was used as a conductive filler and PPy as an impedance regulator. The minimum reflection loss of the composite fabric reached –27dB, and the effective absorption bandwidth covered the entire X-band. Tian et al. grew a Co3O4 array structure on a flexible carbon cloth substrate through a static growth and annealing process. The final electromagnetic wave absorption composite material had a minimum reflection loss of –54.64dB and an effective absorption bandwidth of 4.54GHz. However, in actual applications, electromagnetic wave absorption composite materials often need to face many complex and harsh environments, such as acidic, alkaline, high temperature, and high temperature environments, which will affect the physical and chemical properties of their surfaces, thereby affecting their absorption performance of electromagnetic waves. Therefore, a single electromagnetic wave absorption performance cannot meet the stringent requirements of future wars.

[0005] In the past decade, the research on multifunctional superhydrophobic powders and aerogels with electromagnetic wave absorption performance has been widely studied. Yang et al. prepared hierarchically doped hollow carbon microspheres by a low-cost and simple method. While maintaining superhydrophobic performance, they achieved a strong reflection loss of -61.2dB at a low filler content of 15% and an ultra-thin thickness of 1.45mm. Zhou et al. used NiCo-MOF as a precursor and self-assembled CoNi / C aerogels by water-induced method, which have excellent superhydrophobic properties (water contact angle greater than 140°) and good electromagnetic wave absorption performance (effective absorption bandwidth at 1.9mm reaches 6.22GHz). Although these materials have good electromagnetic wave absorption performance and environmental stability, they have problems such as low strength and high brittleness. When subjected to external forces, the structure is easily damaged, making it difficult to maintain the shape, and the preparation process is relatively complex and harsh, making it difficult to produce in large quantities. In recent years, research on superhydrophobic and self-cleaning electromagnetic wave absorbing fabrics has gradually sprouted. Liu et al. loaded the product of adhesive multi-arm carbon nanotubes (MWCNTs) and hydrophobic octadecanoyl chains on cotton fabrics by dip coating and heat treatment induction, and obtained superhydrophobic fabrics with electromagnetic wave absorption performance, achieving a minimum reflection loss of -36.08dB at a thickness of 2.7mm. Wang et al. constructed a hierarchical nanostructure of MXene / ZnO array / Ni chain on cotton fabrics by dip coating, and the wave absorption performance can be effectively controlled by controlling the number of dip coating of Ni chain. While achieving superhydrophobicity, the minimum reflection loss of the fabric at a thickness of 2.8mm reached -35.1dB, and the effective absorption bandwidth covered the entire X-band. Although these fabric-based superhydrophobic electromagnetic wave absorbing materials have made some progress. However, it is still a huge challenge to achieve the combination of efficient wave absorption performance and excellent superhydrophobic self-cleaning performance on the fabric matrix. Summary of the invention

[0006] In view of the deficiencies in the above-mentioned prior art, a lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric and a preparation method thereof are provided, which has excellent electromagnetic wave absorption performance and super-hydrophobic and self-cleaning performance, and has good stability. At the same time, it has heat insulation and flame retardant properties, as well as good lightness and flexibility, and can be bent and twisted at will. In future applications, it has very broad prospects both in terms of its own lightness and flexibility, and in terms of resistance to harsh environments and safety of use.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is a lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric, which is formed by constructing an rGO / LDH / PPy layer on an aramid non-woven fabric by a hydrothermal method and in-situ growth to form a multi-dimensional heterogeneous structure, and then modified by a low surface energy material modification layer to form a super-hydrophobic absorbing fabric. A conductive network is formed on the one-dimensional interlaced fibers anchoring polypyrrole nanoparticles, with conduction loss as the main factor, and two-dimensional rGO and FeCo-LDH respectively provide dielectric loss and magnetic loss for impedance matching adjustment, and a three-dimensional fluffy and porous aramid fiber skeleton performs multiple reflections and scattering of electromagnetic waves. At the same time, the multi-dimensional heterogeneous interface enhances the interface loss, and the design and construction of the multi-component, multi-dimensional heterogeneous structure jointly cooperate with the synergistic effect of multiple loss mechanisms, so that the composite fabric exhibits electromagnetic wave absorption performance; due to the synergistic effect of the surface roughness provided by the multi-dimensional heterogeneous structure and the modification of the low surface energy material, the air layer is trapped in the matrix of the rGO / LDH / PPy layer, thereby forming a stable Cassie–Baxter state.

[0008] The above-mentioned lightweight, superhydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric has a minimum reflection loss of –45.0 dB at a thickness of 3.5 mm at a low loading of 15 wt%. In the wide thickness range of 3.0-3.5 mm, the effective absorption bandwidth can cover the entire X-band.

[0009] The light, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric has a water contact angle of 156.9°.

[0010] The above-mentioned lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric has a gram weight of ~170g / m 2 .

[0011] The above-mentioned lightweight, superhydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric can stably retain spherical droplets on its surface for at least 30 minutes.

[0012] The above-mentioned lightweight, superhydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric was immersed in strong acid (HCl, PH=1), strong base (NaOH, PH=14), cyclohexane (CYH), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and tetrahydrofuran (THF) chemical solutions for 24 hours, and then rinsed with tap water and dried at room temperature. The WCAs were 155.7°, 154.5°, 154.6°, 152.9°, 154.4° and 155°, respectively.

[0013] The above-mentioned lightweight, superhydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric has a WCA of 153.4° after 100 cycles of tape rapid stripping operation.

[0014] The above-mentioned lightweight, superhydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric can still reach a water contact angle of 153.2° and 155.2° after being placed in 80°C hot water and -20°C environment for 12 hours.

[0015] The method for preparing the above-mentioned lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric comprises the following steps:

[0016] (1): Graphene oxide (GO) was prepared by the traditional Hummers method with a concentration of 12-14 mg / g; rGO / FeCOLDH composites were prepared by a simple hydrothermal method: 1.4-1.6 g GO was ultrasonically dispersed in 30 mL water for 1-1.5 h to obtain a GO few-layer nanosheet dispersion, and aramid nonwoven fabric (ANF) washed repeatedly with deionized water and ethanol was immersed in the GO dispersion and dried at 50-60 °C to obtain GO-modified fabric (GO-MF);

[0017] (2): FeCo-LDH was prepared by hydrothermal method, and GO was partially reduced: 0.2-0.3gCo(NO3)

[0018] 2·6H2O and 0.1-0.2gFe(NO3)2·9H2O were dissolved in a mixed solvent of 10-15mL ethanol and 40-45mL deionized water. After being fully dissolved, the mixed solution was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, immersed in GO-MF, reacted at 120°C for 20-24h, and then slowly cooled to room temperature. The fabric was taken out and dried at 50-60°C to obtain the fabric modified with rGO and FeCo-LDH (GL-MF);

[0019] (3): Loading polypyrrole on the fabric by in-situ polymerization: immerse GLMF in 1-1.2 MFeCl3·6H2O for 15-20 min, drain and remove liquid, then quickly immerse in 10% pyrrole monomer solution for in-situ polymerization for 1 h at 60-70 °C

[0020] After drying at 400 °C, rGO / FeCo-LDH / PPy modified fabric (GLP-MF) was obtained;

[0021] (4): The above fabric is immersed in a 5-6% SN-67 solution, and then dried at 80-90°C to obtain a super hydrophobic absorbing fabric (GLPS-MF).

[0022] The method for preparing the above-mentioned lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric comprises the following steps:

[0023] (1): Graphene oxide (GO) was prepared by the traditional Hummers method with a concentration of 13.99 mg / g; rGO / FeCO-LDH composite material was prepared by a simple hydrothermal method: 1.5 g GO was ultrasonically dispersed in 30 mL water for 1 h to obtain a GO few-layer nanosheet dispersion, and aramid nonwoven fabric (ANF) washed repeatedly with deionized water and ethanol was immersed in the GO dispersion and dried at 60 °C to obtain GO modified fabric (GO-MF);

[0024] (2): FeCo-LDH was prepared by a hydrothermal method, and GO was partially reduced: 0.2965g Co(NO3)2·6H2O and 0.1276g Fe(NO3)2·9H2O were dissolved in a mixed solvent of 10mL ethanol and 40mL deionized water. After the mixed solution was fully dissolved, it was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, immersed in GO-MF, and reacted at 120℃ for 24h. After slowly cooling to room temperature, the fabric was taken out and dried at 60℃ to obtain the fabric modified with rGO and FeCo-LDH (GL-MF);

[0025] (3): Polypyrrole was loaded on the fabric by in situ polymerization: GLMF was immersed in 1MFeCl3·6H2O for 15 min, and after draining without liquid dripping, it was quickly immersed in 10% pyrrole monomer solution for in situ polymerization for 1 h, and dried at 60 °C to obtain rGO / FeCo-LDH / PPy modified fabric (GLP-MF);

[0026] (4): The above fabric was immersed in a 5% SN-67 solution and then dried at 80°C to obtain a super hydrophobic absorbing fabric (GLPS-MF).

[0027] The invention discloses a lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric and a preparation method thereof. The beneficial effect is that a multifunctional composite fabric with a multidimensional heterogeneous structure is developed by a hydrothermal method and an in-situ growth method. A conductive network is formed on the one-dimensional interlaced fibers anchoring 0-dimensional polypyrrole nanoparticles, with conduction loss as the main factor. The two-dimensional rGO and FeCo-LDH provide dielectric loss and magnetic loss respectively for impedance matching adjustment. The three-dimensional fluffy and porous aramid fiber skeleton performs multiple reflections and scattering of electromagnetic waves. At the same time, the multi-dimensional heterogeneous interface enhances the interface loss. The design and construction of the multi-component and multi-dimensional heterogeneous structure work together with the synergistic effect of multiple loss mechanisms, so that the composite fabric exhibits excellent electromagnetic wave absorption performance: at 3.5 mm, a minimum reflection loss of -45.0 dB can be achieved. At the same time, within a wide thickness range of 3.5 mm-5.5 mm, the effective absorption bandwidth of the composite fabric can cover the entire X-band. In addition, the composite fabric is also multifunctional. The lightweight and soft composite absorbing fabric has excellent super-hydrophobic and self-cleaning properties and good stability. At the same time, the composite fabric has heat insulation and flame retardant properties. These versatility enables it to cope with a variety of harsh environments and has a certain degree of safety in use.

[0028] In GLPS-MF, the hierarchical morphology formed by the multidimensional heterogeneous surface composed of rGO, FeCo LDH and PPy greatly enriches the surface roughness of the fiber. At the same time, the low surface energy material SN-67 hydrophobically modifies its surface, greatly reducing its surface energy and giving the fabric excellent superhydrophobic properties. It also has excellent water repellency to various liquid stains.

[0029] Due to the synergistic effect of the perfect surface roughness provided by the multidimensional heterogeneous structure and the low surface energy material modification, the air layer is easily trapped in the matrix of the coating, thus forming a stable Cassie–Baxter state, which not only has excellent hydrophobicity to prevent the matrix from being penetrated by droplets, but also exhibits self-cleaning properties. When water droplets fall on the GLPS–MF surface contaminated with soil dirt, the water droplets can quickly roll off and take away the soil dust.

[0030] The excellent flame retardant properties of GLPS-MF were demonstrated by the vertical combustion method. After a 180-second combustion test, the fabric was still not ignited. In addition, GLPS-MF has good lightness and flexibility, and can be bent and twisted at will. In future applications, it has very broad prospects in terms of its own lightness and flexibility, resistance to harsh environments, and safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a flow chart of the preparation process of the present invention;

[0032] Figure 2The scanning electron microscope images of ANF (a), GL–MF (b), GLP–1–MF (c), GMF–2–MF (d), GMF–3–MF (e), and GLPS–MF (f) and the EDS result image of GLPS–MF (g) in Example 2;

[0033] Figure 3 is the XPS spectrum of GLPS-MF in Example 2;

[0034] Figure 4 The real part of the dielectric constant ε′ (a), the imaginary part of the dielectric constant (b), the dielectric loss (c), the Cole-Cole semicircle number statistics (d), the real part of the magnetic permeability (e), the imaginary part of the magnetic permeability (f), the magnetic loss (g), the C0 curve of GLPSMF (h) and the Cole-Cole curves of GOMF (i), GLMF (j), GLPMF (k), and GLPSMF (l) in Example 2;

[0035] Figure 5 3D and 2D absorption performance diagrams of GO–MF (a1, a2), GL–MF (b1, b2), GLP–MF (c1, c2) and GLPS–MF (d1, d2) in Example 2; minimum reflection loss bar graph of GO–MF, ​​GL–MF, GLP–MF and GLPS–MF (e); 2D reflection loss graph at a thickness of 3.5 mm (f); attenuation constant α (g), impedance matching graph Z (h);

[0036] Figure 6 is a diagram of the wave absorption mechanism of Example 2;

[0037] Figure 7 In Example 2, the super hydrophobic properties of the fabric (a) water repellency to various liquids (b) silver mirror image (c) self-cleaning performance (d) organic solvent repellency (e) adhesive fastness (f) low / high temperature resistance (g) thermal insulation performance (h) flexibility (i) flame retardant performance (j); DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] A lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric and a preparation method thereof are provided. The super-hydrophobic absorbing fabric is formed by constructing an rGO / LDH / Ppy layer on an aramid non-woven fabric by a hydrothermal method and in-situ growth to form a multi-dimensional heterogeneous structure, and then being modified by a low surface energy material modification layer. A conductive network is formed on one-dimensional interlaced fibers anchoring polypyrrole nanoparticles, with conduction loss as the dominant factor. Two-dimensional rGO and FeCo-LDH respectively provide dielectric loss and magnetic loss for impedance matching adjustment. A three-dimensional fluffy and porous aramid fiber skeleton performs multiple reflections and scattering of electromagnetic waves. At the same time, the multi-dimensional heterogeneous interface enhances the interface loss. The design and construction of the multi-component and multi-dimensional heterogeneous structure work together with the synergistic effect of multiple loss mechanisms, so that the composite fabric exhibits electromagnetic wave absorption performance. Due to the synergistic effect of the surface roughness provided by the multi-dimensional heterogeneous structure and the modification of the low surface energy material, the air layer is trapped in the matrix of the rGO / LDH / Ppy layer, thereby forming a stable Cassie–Baxter state. Its weight is ~235g / m 2 The aramid nonwoven fabric has a grammage per square meter of 148 g / m 2 , thickness 1.5mm.

[0040] Example 1

[0041] The method for preparing the above-mentioned lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric comprises the following steps:

[0042] (1) Graphene oxide (GO) was prepared by the traditional Hummers method with a concentration of 12 mg / g; rGO / FeCO-LDH composite material was prepared by a simple hydrothermal method: 1.4 g GO was ultrasonically dispersed in 30 mL water for 1.1 h to obtain a GO few-layer nanosheet dispersion, and aramid nonwoven fabric (ANF) washed repeatedly with deionized water and ethanol was immersed in the GO dispersion and dried at 50 °C to obtain GO modified fabric (GO-MF);

[0043] (2): FeCo-LDH was prepared by a hydrothermal method, and GO was partially reduced: 0.2g Co(NO3)2·6H2O and 0.1g Fe(NO3)2·9H2O were dissolved in a mixed solvent of 11mL ethanol and 41mL deionized water. After the mixed solution was fully dissolved, it was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, immersed in GO-MF, and reacted at 120℃ for 20h. After slowly cooling to room temperature, the fabric was taken out and dried at 50℃ to obtain the fabric modified with rGO and FeCo-LDH (GL-MF);

[0044] (3): Polypyrrole was loaded on the fabric by in situ polymerization: GL-MF was immersed in 1.1 MFeCl3·6H2O for 15 min, and after being drained, it was quickly immersed in 10% pyrrole monomer solution for in situ polymerization for 1 h, and dried at 62 °C to obtain rGO / FeCo-LDH / PPy modified fabric (GLP-MF);

[0045] (4): The above fabric was immersed in a 5.3% SN-67 solution and then dried at 82°C to obtain a super hydrophobic absorbing fabric (GLPS-MF).

[0046] Example 2

[0047] The same parts as those in Example 1 are not described in detail here. The difference between the present embodiment and Example 1 is that the method for preparing a lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric comprises the following steps:

[0048] (1): Graphene oxide (GO) was prepared by the traditional Hummers method with a concentration of 13.99 mg / g; rGO / FeCOLDH composite material was prepared by a simple hydrothermal method: 1.5 g GO was ultrasonically dispersed in 30 mL water for 1 h to obtain a GO few-layer nanosheet dispersion, and aramid nonwoven fabric (ANF) washed repeatedly with deionized water and ethanol was immersed in the GO dispersion and dried at 60 °C to obtain GO-modified fabric (GO–MF);

[0049] (2): FeCo–LDH was prepared by a hydrothermal method, and GO was partially reduced at the same time: 0.2965 g Co(NO3)2·6H2O and 0.1276 g Fe(NO3)2·9H2O were dissolved in a mixed solvent of 10 mL ethanol and 40 mL deionized water. After the mixed solution was fully dissolved, it was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, immersed in GO–MF, ​​and reacted at 120°C for 24 h. After slowly cooling to room temperature, the fabric was taken out and dried at 60°C to obtain the fabric modified with rGO and FeCo–LDH (GL–MF);

[0050] (3): Polypyrrole was loaded on the fabric by in situ polymerization: GL-MF was immersed in 1MFeCl3·6H2O for 15 min, and after being drained, it was quickly immersed in 10% pyrrole monomer solution for in situ polymerization for 1 h. After drying at 60 °C, rGO / FeCo–LDH / PPy modified fabric (GLP–MF) was obtained;

[0051] (4): The above fabric was immersed in a 5% SN-67 solution and then dried at 80°C to obtain a super hydrophobic absorbing fabric (GLPS-MF).

[0052] The morphology and microstructure of the materials and fabrics were measured using a Sigma300 scanning electron microscope (SEM) at an accelerating voltage of 5 kV, and the elemental composition of GLPS-MF was recorded using an OxfordAZtecLiveOne X-Max 20 energy dispersive spectrometer (EDS) at 10 kV. The composition and structure of the surface materials of different fabrics were characterized by an Ultima IV X-ray diffractometer (XRD) and an Axis Supra+ X-ray photoelectron diffractometer (XPS). The electromagnetic parameters of the composite fabrics were tested by the waveguide method using an E5080B ENA vector network analyzer in the X-band (8 GHz–12.4 GHz). The test samples were cut into 25*40 mm 2 The fabric is rectangular and clamped into the waveguide fixture of the X-band for measurement. The thickness of the fabric is measured by a screw micrometer.

[0053] Scanning electron microscopy (SEM) was used to characterize the microstructures of ANF, GO–MF, ​​GL–MF, GLP–MF, and GLPS–MF, respectively. Figure 2 (bf) Compared with the smooth fiber surface of ANF ( Figure 2 b), the GL–MF surface can be observed to have an obvious rough surface ( Figure 2 c). Sheet-like stacking was observed on the surface of GL–MF, which may be rGO nanosheets. In addition, multiple small sheets were anchored on the surface, which should be FeCo–LDH ( Figure 2 d), after in situ polymerization of PPy on the fiber surface, Figure 2 In Figure e, granular polypyrrole nanoparticles were observed on the surface of GLP-MF, proving the successful polymerization of polypyrrole. Figure 2 e and Figure 2 f, it can be seen that the surface of GLPS–MF is obviously covered by a layer of transparent material, namely, a hydrophobic coating with low surface energy. Figure 2 g is the EDS test result of GLPS-MF, from which it can be seen that C, O, N, Fe, Co and Si elements are evenly distributed on the surface of the fiber. The observation of microstructure and the uniform distribution of characteristic elements of each component material preliminarily prove that rGO, FeCo-LDH, PPy and SN-67 have been successfully loaded on the surface of the fabric.

[0054] XPS was used to analyze the elemental composition and detailed valence states of GLPS–MF. Figure 3 As shown in a, the XPS spectrum shows that the sample GLPS-MF contains characteristic peaks of C1s, O1s, Fe2p, N1s and 52p. Figure 3 The valence state analysis of each element can be seen in the high-resolution XPS spectra of b–f. Figure 3b, C1s is deconvoluted into three peaks with binding energies of 284.7eV, 285.5eV, and 288.9eV, corresponding to C–C / C=C, C–O, and C=O, respectively. It can be seen that C–C / C=C accounts for a large proportion in this substance. Figure 3 In c, O1s is deconvoluted into three peaks, showing three different oxygen contributions. The peak with a binding energy of 529.7 eV corresponds to O–Mental. Specifically, the metals in O–Mental refer to two magnetic metals, Fe and Co. 531.3 eV and 532.7 eV represent oxygen vacancies and oxygen adsorbed on the sample surface, respectively. The presence of oxygen vacancies can capture charge carriers generated under the action of the alternating electromagnetic field, resulting in the accumulation of negative charges, thereby causing polarization losses and enhancing the electromagnetic wave absorption performance. Figure 3 In d, Fe2p is deconvoluted into six peaks with binding energies of 709.8 eV, 710.8 eV, 714.8 eV, 724.3 eV, 728.7 eV, and 732.5 eV, including four spin-orbit doublets and two satellite peaks. Figure 3 As shown in e, in the spectrum of N1s, the binding energies are 399.7 eV, 400.1 eV and 401.7 eV corresponding to pyridine N, pyridine acid N and graphite N respectively. Figure 3 In f, 52p is deconvoluted into two peaks, and the peaks with binding energies of 101.9 eV and 102.6 eV are attributed to Si–O and Si–O–C, respectively.

[0055] Electromagnetic performance analysis

[0056] The electromagnetic parameters of GO–MF, ​​GL–MF, GLP–MF and GLPS–MF samples in the X-band were tested by the waveguide method using a vector network analyzer. Figure 4 As shown. Generally speaking, a larger dielectric constant (ε) and magnetic permeability (μ) of electromagnetic wave absorbing materials are necessary conditions for higher wave absorbing performance. The dielectric loss tangent (tanε=ε″ / ε′) and (tanμ=μ″ / μ′) determine the material's ability to lose electromagnetic waves. The real part (ε′) and imaginary part (ε″) of the complex dielectric constant represent the material's storage and loss of electrical energy, respectively. Figure 4 (a, b) It can be seen that the ε″ of GO-MF is almost zero, which is a typical wave-transmitting material. The ε′ of GL-MF is significantly greater than that of GO-MF, indicating that after GO is partially reduced, the sample's ability to store electrical energy is improved, but its ability to lose electrical energy remains almost unchanged ( Figure 4c). With the introduction of polypyrrole, the ε′ and ε″ of the samples are significantly improved, which is mainly attributed to the high conductivity of polypyrrole. However, after the fabric is further modified to be superhydrophobic, the dielectric properties decrease. This is mainly due to the different dielectric properties of the hydrophobic agent and polypyrrole, which causes the charge to be rearranged. At the same time, the ε′ and ε″ of GLP-MF and GLPS-MF continue to decrease with the increase of frequency, showing strong dispersion (FD) characteristics. This is because the polarization response of the material cannot keep up with the change of the electric field under the alternating electric field. Generally, strong dispersion characteristics are an important condition for determining whether a material can achieve strong electromagnetic wave absorption at ultra-thin thickness.

[0057] According to the Debye principle, the relationship between the real and imaginary parts of the dielectric constant can be expressed as formula (1):

[0058]

[0059] where ε s represents the static dielectric constant, ε ∞ Represents the relative dielectric constant in the high-frequency limit. The ε′-ε″ curve is called the Cole–Cole curve, and each semicircle on the curve represents a polarization–relaxation process. Figure i is the Cole–Cole curve of GOMF. No obvious semicircle is observed in the curve, indicating that there is no polarization relaxation process. However, after partial reduction of GO and in-situ growth of FeCoLDH, there are multiple semicircles in the Cole–Cole curve of GL–MF, proving that it has multiple polarization relaxation processes ( Figure 4 j). However, the Cole–Cole curve of GLP–MF has only slight fluctuations at the head and the majority of the Cole–Cole curve exhibits linear characteristics, indicating that the conductivity loss of GLP–MF is dominant ( Figure 4 k). However, for GLPS-MF, there is an obvious semicircle in the lower frequency range and a slight fluctuation in the middle of the X-band, indicating that the sample has a polarization relaxation process in these two bands. In addition, there is also a linear part in this Cole-Cole curve, proving the existence of conductive loss ( Figure 4 l). Figure 4 In d, by comparing the number of semicircles of the Cole-Cole curves of different samples, it can be seen that GL-MF is mainly polarization loss. When the fabric is polymerized with pyrrole, a conductive network is formed on the surface of GLP-MF, and the loss of electromagnetic waves is mainly conduction loss. However, after GLP-MF is superhydrophobic modified, the polarization relaxation process of GLPS-MF increases again, which may be attributed to the difference in dielectric properties of GLP-MF after hydrophobic modification, resulting in the redistribution of charges in different components, causing interface loss, thereby enhancing the contribution of polarization loss to electromagnetic wave loss.

[0060] The real part (μ′) and imaginary part (μ″) of the complex magnetic permeability represent the material's storage and loss properties of magnetic energy, respectively. Figure 4 As shown in (d–f), μ′ of GO–MF is close to 1 and μ″ is close to 0. This is because GO–MF does not have magnetic components and is not magnetic. The complex permeability and magnetic loss tangent of GLP–MF and GLPS–MF are almost similar, indicating that the storage and loss capabilities of different samples for magnetic energy are roughly the same. This is because the types and contents of magnetic substances in different samples are the same. C 0 The mechanism used to explain magnetic loss is usually expressed by formula (2):

[0061] C 0 =μ″(μ′) -2 f -1 (2)

[0062] Generally speaking, if C 0 is a straight line that is independent of frequency, then the magnetic loss is mainly realized by eddy current loss. Figure 4 As shown in (h), when the frequency range is less than 10 GHz, C 0 It changes with the frequency, indicating that the magnetic loss is realized by natural resonance, exchange resonance and eddy current loss at the same time. When the frequency range is greater than 10GHz, C 0 It is almost flat and has nothing to do with frequency changes, indicating that the magnetic loss in this frequency band is mainly caused by eddy current loss.

[0063] Figure 4 Real part of dielectric constant ε′ (a), imaginary part of dielectric constant (b), dielectric loss (c), Cole-Cole semicircle number statistics (d), real part of magnetic permeability (e), imaginary part of magnetic permeability (f), magnetic loss (g), C0 curve of GLPSMF (h) and Cole-Cole curves of GOMF (i), GLMF (j), GLPMF (k), GLPSMF (l)

[0064] Electromagnetic wave absorption performance

[0065] The absorption performance of electromagnetic waves is determined by the attenuation performance (α) and impedance matching (Z) of the material, and neither of them can be missing. Through the transmission line theory, the reflection loss value (R L ) is used to evaluate its electromagnetic wave absorption performance, which is expressed by formula (3)(4)(5):

[0066]

[0067]

[0068]

[0069] Where Z is the normalized impedance, Z in is the input impedance of the fabric, Z 0 is the impedance of free space, h is Planck's constant, f is the frequency, d is the thickness of the material, and c is the speed of light. Usually, the attenuation constant (α) determines the material's ability to attenuate electromagnetic waves. The larger the α value, the stronger the material's ability to attenuate electromagnetic waves. The impedance matching value (Z) determines whether the electromagnetic wave can enter the interior of the material and be absorbed. The closer Z is to 1, the greater the electromagnetic wave can enter the material and be lost. Figure 5 (a–c) are the reflection losses (R L ) 2D, 3D graphs and a bar graph of minimum reflection loss. Figure 5 (a1, a2) It can be seen that the minimum reflection loss of GO-MF at 5.5 mm is –18.1 dB, and there is almost no effective absorption bandwidth in the X-band, due to the single dielectric loss mechanism of GO-MF. After partial reduction of GO on its surface and in-situ growth of FeCo-LDH, the absorption performance has been significantly enhanced. The minimum reflection loss of GL-MF at 3 mm and 3.5 mm reaches –39.6 dB and –27.9 dB, respectively, and the effective absorption bandwidth in the X-band is 1.2 GHz at 4.5 mm ( Figure 5 b1, b2). This indicates that after high-temperature reduction of GO, some rGO is produced, which enriches the dielectric loss mechanism between the hierarchical structures and increases certain conduction losses, which is beneficial to the further absorption of electromagnetic waves. More importantly, the in-situ growth of FeCo–LDH increases magnetic losses, improves impedance matching, and optimizes the loss mechanism. After modification with polypyrrole, the absorption properties of the modified fabric for electromagnetic waves are further enhanced. The minimum reflection loss values ​​of GLPMF at 3mm and 3.5mm are –24.5dB and –45.6dB, respectively, and the effective absorption bandwidth covers the X-band in the entire thickness range of 3mm3.5mm ( Figure 5 c1, c2). Most importantly, after being super-hydrophobic, the fabric can still maintain stable and efficient electromagnetic wave absorption performance, with the minimum reflection loss reaching –45.0 dB at 3.5 mm ( Figure 5 d1, d2), only the minimum reflection loss is slightly lower than GLPMF. The reason may be that the PPy particles fall off during the superhydrophobic modification process. Figure 5 e shows the absorption performance of different fabric samples at different thicknesses more clearly and intuitively. By comparing the reflection loss of the fabric at 3.5 mm, it can be found that after the fabric is modified with LDH and PPy, the electromagnetic wave absorption performance is significantly enhanced twice. The reasons are as follows: Figure 5As shown in g and h, the magnitude relationship of the attenuation loss value α is GPL–MF>GL–MF>GO–MF, ​​indicating that the attenuation capacity of the two modifications has been improved. Figure 5 h, the Z value of GLP-MF is closest to 1, indicating that its impedance matching is the best, and more electromagnetic waves enter the material and are absorbed. After superhydrophobic modification, the electromagnetic wave absorption performance of GLPMF and GLPSMF is similar, but the minimum reflection loss value moves forward from 10.3 GHz to 8.2 GHz, indicating that the electromagnetic wave absorption mechanism of the fabric after superhydrophobic modification has changed (further explained in the next section), affecting the electromagnetic wave absorption intensity in different frequency bands, but superhydrophobic modification will not affect the electromagnetic wave absorption performance of the fabric.

[0070] Wave absorption mechanism

[0071] Figure 6 The electromagnetic wave absorption mechanism of GLPS–MF is explained. The rich electromagnetic wave loss mechanism mainly comes from the design of multidimensional heterogeneous structure and interface engineering. These include the conduction loss of 0-dimensional polypyrrole nanoparticles, the anisotropy of one-dimensional aramid fiber, the polarization (dipole polarization and interface polarization) and magnetic loss of two-dimensional materials, and the multiple reflections and scattering of three-dimensional networks, which together determine the adjustment of impedance matching and the optimization of attenuation performance. First, rGO is produced after in-situ hydrothermal reduction of GO. There are a large number of defects and functional groups on its surface or edge, which will capture charge carriers, break the balance of charge distribution, and cause the dipole to deflect or displace under alternating induction, resulting in polarization process, thereby losing electromagnetic waves. At the same time, PPy nanoparticles are evenly distributed on aramid fibers to form a conductive network. When electromagnetic waves are incident on the material, the electrons and holes on the fiber surface will transition and jump under the excitation of the electric field force, generating microcurrents. Due to the existence of resistance, the current will be dissipated in the form of heat energy, thereby achieving the loss of electromagnetic waves. Secondly, the multi-dimensional heterostructure gives the material a rich interface. Due to the difference in node characteristics and the conductivity of different components, the carriers gather from low work function to high work function, and then a polarization relaxation process occurs under the change of electric field, that is, interface polarization. In addition, the presence of FeCoLDH causes magnetic loss in the material, and its mechanism includes natural resonance and eddy current resonance. Finally, the staggered and overlapping aramid fibers allow electromagnetic waves to be reflected and scattered multiple times, increasing the distance of the incident wave, thereby enhancing the loss of electromagnetic waves by the modified fabric. In short, the design of the multi-dimensional heterostructure and multiple loss mechanisms give the modified fabric excellent electromagnetic wave absorption performance.

[0072] Multifunctional properties of fabrics

[0073] Electromagnetic wave absorbing fabrics are often subjected to many harsh environments during use. Therefore, the presence of superhydrophobic properties will improve the durability and stability of the coated fabrics. In GLPS-MF, the hierarchical morphology formed by the multidimensional heterogeneous surface composed of rGO, FeCo LDH and PPy greatly enriches the surface roughness of the fiber. At the same time, the low surface energy material SN-67 hydrophobically modifies its surface, greatly reducing its surface energy and giving the fabric excellent superhydrophobic properties with a WCA of 156.9° (Fig.7a). In addition to water, Figure 7 b shows the excellent water repellency of the superhydrophobic coating fabric to various liquid stains. Spherical droplets of various aqueous solutions such as strong acid (HCl, pH = 1), strong alkali (NaOH, pH = 14), milk, orange juice and tea can stay stably on its surface for at least 30 minutes without diffusing into the fabric matrix. When GLPS-2-M is immersed in water, the bubbles on the surface of the submerged area gather to form an air cushion and produce light reflection, presenting a bright silver mirror effect ( Figure 7 c). Due to the synergistic effect of the perfect surface roughness provided by the multidimensional heterogeneous structure and the low surface energy material modification, the air layer is easily trapped in the matrix of the coating, thus forming a stable Cassie–Baxter state, which not only has excellent hydrophobicity to prevent the matrix from being penetrated by droplets, but also exhibits self-cleaning properties. When water droplets fall on the surface of GLPS–MF contaminated with soil dirt, the water droplets can quickly roll off and take away the soil dust ( Figure 7 d). The chemical corrosion resistance of GLPS–MF was evaluated, e.g. Figure 7 As shown in e. After the samples were immersed in chemical solutions such as strong acid (HCl, PH = 1), strong base (NaOH, PH = 14), cyclohexane (CYH), N, N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and tetrahydrofuran (THF) for 24 hours, rinsed with tap water and dried at room temperature, the WCA were 155.7°, 154.5°, 154.6°, 152.9°, 154.4° and 155°, respectively, still maintaining superhydrophobicity, and SA increased slightly by 7.3°, 7.5°, 7.6°, 8.6°, 7.5° and 6.9°. In addition, GLPS-MF also has a certain peeling resistance, such as Figure 7 f. After 100 cycles of tape rapid peeling, the water contact angle can still be maintained above 150°, and the WCA is 153.4°. Figure 7 g shows the stable superhydrophobic property of GLPS–MF. After GLPS–MF was placed in 80°C hot water and –20°C environment for 12 h, the water contact angle could still reach 153.2° and 155.2°.

[0074] In practical applications, fabrics often need to cope with more complex and harsh environments. Therefore, in addition to the stealth performance against radar waves brought by the electromagnetic wave absorption performance, certain thermal stealth performance (i.e. infrared stealth performance) and flame retardant properties are also required to work together from multiple aspects to reduce the detectability of the target. Figure 7 h is the test result of infrared stealth performance of modified fabric. Cotton fabric, aramid nonwoven fabric and GLPS-MF were placed on a heating platform at 60℃ at the same time. As can be seen from the figure, ANF and GLPS-MF formed a sharp contrast with the red color of the heating platform, while the color of cotton fabric had merged with the heating platform within 30s. This phenomenon is mainly attributed to the low density and porous structural characteristics of aramid nonwoven fabric itself. A large number of pores can effectively block the transfer of heat. Figure 7 j, the excellent flame retardant properties of GLPS-MF were demonstrated by the vertical combustion method. After 180s of burning test, the fabric was still not ignited. The reason for this was mainly due to the presence of flame retardant substances in the fabric and the porous structure. Last but not least, GLPS-MF has good lightness and flexibility ( Figure 7 i) It can be bent and twisted at will, and has very broad prospects in future applications, whether in terms of its own lightness and flexibility, or in terms of resistance to harsh environments and safety of use.

[0075] The rGO / LDH / PPy electromagnetic wave absorbing composite fabric with multidimensional heterogeneous structure was constructed on high-strength, high-modulus, high-temperature resistant aramid non-woven fabric by hydrothermal method and in-situ growth. Finally, at a low loading of 15wt%, the minimum reflection loss of the composite fabric at a thickness of 3.5mm reached –45.0dB, and the effective absorption bandwidth in a wide thickness range (3.0–3.5mm) can cover the entire X-band. More importantly, the lightweight and flexible rGO / LDH / PPy electromagnetic wave absorbing composite fabric not only ensures excellent electromagnetic wave absorption performance, but also has excellent superhydrophobic, self-cleaning performance (water contact angle exceeds 150°) and good thermal insulation and flame retardant properties. Thanks to the construction of multidimensional heterogeneous structure, this nanoscale rough structure is conducive to the formation of superhydrophobic surface, which provides an effective idea for designing flexible superhydrophobic and self-cleaning electromagnetic wave absorbing fabrics, and has broad development prospects in aerospace, radar stealth and other fields in the future.

[0076] Example 3

[0077] The same parts as those in Example 1 are not described in detail here. The difference between the present embodiment and Example 1 is that the method for preparing the above-mentioned lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric comprises the following steps:

[0078] (1) Graphene oxide (GO) was prepared by the traditional Hummers method with a concentration of 14 mg / g; rGO / FeCO-LDH composite material was prepared by a simple hydrothermal method: 1.6 g GO was ultrasonically dispersed in 30 mL water for 1.5 h to obtain a GO few-layer nanosheet dispersion, and aramid nonwoven fabric (ANF) washed repeatedly with deionized water and ethanol was immersed in the GO dispersion and dried at 58 °C to obtain GO modified fabric (GO-MF);

[0079] (2): FeCo-LDH was prepared by a hydrothermal method, and GO was partially reduced: 0.3g Co(NO3)2·6H2O and 0.2g Fe(NO3)2·9H2O were dissolved in a mixed solvent of 15mL ethanol and 45mL deionized water. After the mixed solution was fully dissolved, it was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, immersed in GO-MF, and reacted at 120℃ for 22h. After slowly cooling to room temperature, the fabric was taken out and dried at 55℃ to obtain the fabric modified with rGO and FeCo-LDH (GL-MF);

[0080] (3): Polypyrrole was loaded on the fabric by in situ polymerization: GLMF was immersed in 1.2MFeCl3·6H2O for 15-20min, and after being drained without liquid dripping, it was quickly immersed in 10% pyrrole monomer solution for in situ polymerization for 1h, and dried at 70°C to obtain rGO / FeCo-LDH / PPy modified fabric (GLP-MF);

[0081] (4): The above fabric was immersed in a 6% SN-67 solution and then dried at 90°C to obtain a super hydrophobic absorbing fabric (GLPS-MF).

[0082] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A lightweight, super-hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric. Features: The super hydrophobic absorbent fabric is formed by constructing rGO / LDH / PPy layers on aramid nonwoven fabric by hydrothermal method and in-situ growth to form a multidimensional heterogeneous structure, and then modified with a low surface energy material modification layer. A conductive network is formed on the one-dimensional interlaced fibers anchoring polypyrrole nanoparticles. The aramid nonwoven fabric (ANF) repeatedly washed with deionized water and ethanol is immersed in GO dispersion and dried at 50-60°C to obtain GO-modified fabric GO-MF; FeCo-LDH is prepared by hydrothermal method, and GO is partially reduced: 0.2965gCo(NO 3 ) 2 6H 2 O and 0.1276 gFe(NO 3 ) 2 9H 2 O was dissolved in a mixed solvent of 10 mL ethanol and 40 mL deionized water. After fully dissolved, the mixed solution was transferred to a stainless steel autoclave with a polytetrafluoroethylene liner, immersed in GO–MF, ​​reacted at 120 °C for 24 h, and then slowly cooled to room temperature. The fabric was taken out and dried at 60 °C to obtain the fabric GL–MF modified with rGO and FeCo–LDH. Polypyrrole was loaded on the fabric by in situ polymerization: GL–MF was immersed in 1 MFeCl 3 6H 2 O for 15 min, and after draining without liquid dripping, it was quickly immersed in 10% pyrrole monomer solution for in situ polymerization for 1 h, and then dried at 60 °C to obtain the rGO / FeCo–LDH / PPy modified fabric GLP–MF.

2. The lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 1, Its characteristic is that At a low loading of 15wt%, the minimum reflection loss of the composite fabric at a thickness of 3.5mm reaches –45.0dB, and within a wide thickness range of 3.0–3.5mm, the effective absorption bandwidth can cover the entire X-band.

3. The lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 1, Its characteristics are: Its water contact angle is 156.9°.

4. The lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 3, Its characteristics are: The spherical droplets can stay stably on its surface for at least 30 minutes.

5. The lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 1, Its characteristics are: After being immersed in chemical solutions of HCl, pH=1, NaOH, pH=14, cyclohexane (CYH), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) and tetrahydrofuran (THF) for 24 h, rinsed with tap water and dried at room temperature, the WCA were 155.7°, 154.5°, 154.6°, 152.9°, 154.4° and 155°, respectively.

6. The lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 5, Its characteristics are: After 100 cycles of tape rapid peeling operation, the WCA was 153.4°.

7. The lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 6, Its characteristics are: After being placed in 80°C hot water and –20°C environment for 12 hours, the water contact angle can still reach 153.2° and 155.2°.

8. A method for preparing a lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to any one of claims 1 to 7, It is characterized in that The following steps are involved: (1): Graphene oxide (GO) was prepared by the conventional Hummers method at a concentration of 12-14 mg / g; 1.4-1.6 g GO was ultrasonically dispersed in 30 mL water for 1-1.5 h to obtain a GO few-layer nanosheet dispersion, and an aramid nonwoven fabric (ANF) that had been repeatedly washed with deionized water and ethanol was immersed in the GO dispersion and dried at 50-60 °C to obtain a GO-modified fabric GO-MF; (2): rGO / FeCOLDH composite material was prepared by a simple hydrothermal method: FeCo–LDH was prepared by hydrothermal method, and GO was partially reduced: 0.2-0.3gCo(NO 3 ) 2 6H 2 O and 0.1-0.2gFe (NO 3 ) 2 9H 2 O was dissolved in a mixed solvent of 10-15 mL ethanol and 40-45 mL deionized water. After being fully dissolved, the mixed solution was transferred to a stainless steel high-pressure reactor with a polytetrafluoroethylene liner, immersed in GO-MF, reacted at 120 °C for 20-24 h, and then slowly cooled to room temperature. The fabric was taken out and dried at 50-60 °C to obtain the fabric GL-MF modified with rGO and FeCo-LDH; (3): Loading polypyrrole on the fabric by in situ polymerization: Immerse GLMF in 1-1.2 MFeCl 3 6H 2 O for 15-20 min, drained and then quickly immersed in 10% pyrrole monomer solution for in-situ polymerization for 1 h, and dried at 60-70 °C to obtain rGO / FeCo-LDH / PPy modified fabric GLP-MF; (4): The above fabric was immersed in 5-6% SN-67 solution and then dried at 80-90 °C to obtain the super hydrophobic absorbing fabric GLPS-MF.

9. The method for preparing the lightweight, super hydrophobic and self-cleaning rGO / LDH / PPy composite absorbing fabric according to claim 8, Its characteristics are: The following steps are involved: (1): Graphene oxide (GO) was prepared by the traditional Hummers method with a concentration of 13.99 mg / g; rGO / FeCOLDH composite material was prepared by a simple hydrothermal method: 1.5 g GO was ultrasonically dispersed in 30 mL water for 1 h to obtain a GO few-layer nanosheet dispersion, and aramid nonwoven fabric (ANF) washed repeatedly with deionized water and ethanol was immersed in the GO dispersion and dried at 60 °C to obtain GO-modified fabric GO–MF; (2): FeCo–LDH was prepared by hydrothermal method, and GO was partially reduced: 0.2965 g Co (NO 3 ) 2 6H 2 O and 0.1276 gFe(NO 3 ) 2 9H 2 O was dissolved in a mixed solvent of 10 mL ethanol and 40 mL deionized water. After being fully dissolved, the mixed solution was transferred to a stainless steel autoclave with a polytetrafluoroethylene liner, immersed in GO–MF, ​​reacted at 120 °C for 24 h, and then slowly cooled to room temperature. The fabric was taken out and dried at 60 °C to obtain the fabric GL–MF modified with rGO and FeCo–LDH; (3): Polypyrrole was loaded on the fabric by in situ polymerization: GLMF was immersed in 1MFeCl 3 6H 2 O for 15 min, and after draining without liquid dripping, it was quickly immersed in a 10% pyrrole monomer solution for in-situ polymerization for 1 h, and dried at 60 °C to obtain the rGO / FeCo–LDH / PPy modified fabric GLP–MF; (4): The above fabric was immersed in 5% SN-67 solution and then dried at 80 °C to obtain the super hydrophobic absorbing fabric GLPS-MF.

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