Cu9S8 / PANI cotton fabric and preparation method and application thereof

Abstract

The invention discloses a Cu9S8 / PANI cotton fabric and a preparation method and application thereof. The preparation method comprises the following steps: dissolving aniline into a dichloromethane solution to obtain an organic phase solution; adding ammonium persulfate and sodium sulfosalicylate into distilled water, and performing ultrasonic treatment to obtain a water-phase solution; ultrasonically cleaning a cotton fabric with deionized water and absolute ethyl alcohol, drying, weighing, soaking in an organic phase solution, placing in a refrigerator, dropwise adding a water phase solution, carrying out sealed reaction to obtain a dark green cotton fabric, washing with distilled water until the cotton fabric is colorless, and drying to obtain a PANI cotton fabric; adding copper sulfate pentahydrate and sodium thiosulfate into distilled water, performing ultrasonic treatment to obtain a reaction solution, and adjusting the pH value of the reaction solution with concentrated sulfuric acid; and putting the PANI cotton fabric into the reaction solution, oscillating at normal temperature, carrying out stepped heating oscillation reaction, taking out the cotton fabric after the reaction, washing the cotton fabric with distilled water until the cotton fabric is colorless, and drying to obtain the Cu9S8 / PANI cotton fabric. The prepared Cu9S8 / PANI cotton fabric has excellent electrical conductivity and electromagnetic shielding effectiveness.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, specifically relating to a Cu9S8 / PANI cotton fabric, its preparation method, and its application. Background Technology

[0002] Research on polyaniline can be traced back to the synthesis of "aniline black" in the 1860s. After the discovery of the conductive polymer polyacetylene in the 1970s, scientists began to study conductive polymers in depth. In the mid-1980s, MacDiarmid et al. discovered that polyaniline could be doped to obtain a highly conductive "emerald green imine". The polyaniline structure contains benzene and quinone rings, and due to different proportions, it exists in three easily achievable oxidation states: fully reduced crypto-emerald green imine, semi-oxidized emerald green imine, and fully oxidized peraniline black, with the emerald green imine having the highest conductivity. Compared with other conductive polymers, polyaniline has a more diverse structure and can generate amino salts through proton doping and p-type doping. Its most common synthesis method is the chemical oxidative polymerization of aniline monomers in acidic solution. This method is simple and suitable for mass production, and is the main commercial method. In the chemical polymerization method, ammonium persulfate is a commonly used strong oxidant. Initially, fully oxidized peraniline black is generated. After the oxidant is depleted, the remaining aniline monomer reduces the peraniline black to obtain the green emerald green imine salt. However, pure polyaniline suffers from low electrical conductivity, which limits its application as a shielding material. Therefore, introducing metals into the polymer matrix is ​​considered to increase the dielectric constant of the fabric, thereby enhancing its electromagnetic shielding effectiveness. Transition metal sulfides, especially copper sulfides, have attracted much attention due to their applications in semiconductors, catalysis, and conductive materials. Known copper sulfide phases are abundant, ranging from Cu₂S to CuS₂, including CuS, Cu… 1.96 Copper sulfide exists in various forms, including S and Cu7S4. However, traditional preparation methods (such as solid-state reaction and self-propagating high-temperature synthesis) typically require temperatures above 500°C, which are demanding and energy-intensive. Using gaseous H2S as a sulfur source is highly toxic and hazardous. Although molecular precursor methods exist (such as thermal decomposition of metal complexes), the resulting products are mostly amorphous, requiring a post-processing crystallization at 250-500°C. Existing low-temperature synthesis processes (such as the liquid ammonia method) have low reaction temperatures but are complex to operate (requiring operation at -77°C under strict protective conditions), and the products are mixtures of various copper sulfides, making it difficult to obtain a single phase, which severely limits their practical application.

[0003] In view of the problems of high energy consumption, high risk, complex process and impure product in the existing technology, the purpose of this invention is to provide a simple, mild, safe and reliable method for preparing Cu9S8. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing Cu9S8 / PANI cotton fabric.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing Cu9S8 / PANI cotton fabric, characterized in that it includes,

[0008] Aniline is dissolved in dichloromethane solution to obtain an organic phase solution;

[0009] Ammonium persulfate and sodium sulfosalicylate were added to distilled water and sonicated to obtain an aqueous solution.

[0010] The cotton fabric was ultrasonically washed with deionized water and anhydrous ethanol, dried, weighed, soaked in an organic phase solution, placed in a refrigerator, and an aqueous phase solution was added dropwise. The reaction was sealed to obtain a dark green cotton fabric. After washing with distilled water until colorless, the fabric was dried to obtain PANI cotton fabric.

[0011] Copper sulfate pentahydrate and sodium thiosulfate were added to distilled water and sonicated to obtain a reaction solution. The pH of the reaction solution was adjusted with concentrated sulfuric acid.

[0012] The PANI cotton fabric was placed in the reaction solution and shaken at room temperature. Then, the reaction was carried out by stepwise heating and shaking. After the reaction, the cotton fabric was taken out, washed with distilled water until colorless, and dried to obtain Cu9S8 / PANI cotton fabric.

[0013] In a preferred embodiment of the preparation method described in this invention, the mass ratio of aniline to dichloromethane solution in the organic phase solution is 1 to 4:80.

[0014] In a preferred embodiment of the preparation method described in this invention, the molar ratio of ammonium persulfate and sodium sulfosalicylate in the aqueous solution is 1:1.

[0015] In a preferred embodiment of the preparation method described in this invention, the concentration of copper sulfate pentahydrate is 3.75–4.75 g / L.

[0016] In a preferred embodiment of the preparation method described in this invention, the concentration of sodium thiosulfate is 4.5–5.5 g / L.

[0017] In a preferred embodiment of the preparation method described in this invention, the concentrated sulfuric acid is used to adjust the pH of the reaction solution to 2-3.

[0018] As a preferred embodiment of the preparation method described in this invention, the step-heating oscillation reaction is carried out at 40°C for 1 hour, at 60°C for 1 hour, and at 80°C for 0.5 hours.

[0019] In a preferred embodiment of the preparation method described in this invention, the concentrated sulfuric acid is used to adjust the pH of the reaction solution to 2.

[0020] Another objective of this invention is to overcome the shortcomings of the prior art and provide a Cu9S8 / PANI cotton fabric prepared by a specific method.

[0021] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of Cu9S8 / PANI cotton fabric in conductive fabrics and electromagnetic shielding fabrics.

[0022] Beneficial effects of this invention:

[0023] This invention employs interfacial polymerization to synthesize polyaniline (PANI) on cotton fabric in situ, and then uses a stepped heating water bath oscillation reaction to prepare Cu9S8 / PANI cotton fabric. The preparation method of this invention is simple, and the prepared Cu9S8 / PANI cotton fabric exhibits excellent electrical conductivity and electromagnetic shielding effectiveness. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0025] Figure 1 SEM images of PANI cotton fabric and Cu9S8 / PANI cotton fabric from embodiments of the present invention: Figure 1 (a) PANI cotton fabric (×10,000), Figure 1 (b) PANI cotton fabric (×25,000), Figure 1 (c) PANI cotton fabric (×100,000), Figure 1 (d)Cu9S8 / PANI cotton fabric (×10,000), Figure 1 (e)Cu9S8 / PANI cotton fabric (×25,000), Figure 1 (f)Cu9S8 / PANI cotton fabric (×100,000).

[0026] Figure 2 The images show the XRD patterns of cotton fabric, PANI cotton fabric, and Cu9S8 / PANI cotton fabric according to embodiments of the present invention.

[0027] Figure 3 The infrared spectra of cotton fabric, PANI cotton fabric, and Cu9S8 / PANI cotton fabric are shown in the embodiments of the present invention.

[0028] Figure 4 The effect of aniline dosage on the weight gain rate of PANI cotton fabric and Cu9S8 / PANI cotton fabric in the embodiments of the present invention.

[0029] Figure 5 This invention relates to the effect of CuSO4·5H2O concentration on the weight gain rate of PANI cotton fabric and Cu9S8 / PANI cotton fabric in the embodiments of the present invention.

[0030] Figure 6 This invention illustrates the effect of Na2S2O3 concentration on the weight gain rate of PANI cotton fabric and Cu9S8 / PANI cotton fabric in specific embodiments.

[0031] Figure 7 The effect of aniline dosage on the electrical conductivity of PANI cotton fabric and Cu9S8 / PANI cotton fabric in the embodiments of the present invention.

[0032] Figure 8 This invention illustrates the effect of CuSO4·5H2O concentration on the electrical conductivity of PANI cotton fabric and Cu9S8 / PANI cotton fabric in specific embodiments.

[0033] Figure 9 This invention illustrates the effect of Na2S2O3 concentration on the electrical conductivity of PANI cotton fabric and Cu9S8 / PANI cotton fabric in various embodiments.

[0034] Figure 10 This invention illustrates the effect of aniline dosage on the electromagnetic shielding effectiveness of PANI cotton fabric and Cu9S8 / PANI cotton fabric in various embodiments.

[0035] Figure 11 This invention relates to the effect of CuSO4·5H2O concentration on the electromagnetic shielding effectiveness of Cu9S8 / PANI cotton fabric in an embodiment of the present invention.

[0036] Figure 12 This invention relates to the effect of Na2S2O3 concentration on the electromagnetic shielding effectiveness of Cu9S8 / PANI cotton fabric in an embodiment of the present invention. Detailed Implementation

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0040] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available. See Table 1 for details.

[0041] Table 1

[0042]

[0043]

[0044] Example 1

[0045] This embodiment provides a method for preparing Cu9S8 / PANI cotton fabric:

[0046] (1) Use a pipette to measure 2 ml of aniline and dissolve it in 85 mL of dichloromethane solution. Stir well to prepare an organic phase solution.

[0047] (2) Weigh 3.5g of ammonium persulfate and 4.22g of sodium sulfosalicylate, add them to 85mL of distilled water, sonicate for 0.5h to prepare an aqueous solution. The molar ratio of aniline to ammonium persulfate and sodium sulfosalicylate is 1:0.8:0.8.

[0048] (3) Cut the cotton fabric into circular samples with a diameter of 10 cm. First, use deionized water and anhydrous ethanol to ultrasonically wash the cut fabric, then dry it at 60°C and weigh it. Soak the washed cotton fabric in the organic phase solution and place it in a refrigerator at 5°C. Add the aqueous phase solution dropwise to the organic phase solution. After sealing and reacting for 24 hours, take out the dark green cotton fabric, wash it with distilled water until the washing solution is colorless, and dry it at 60°C to obtain PANI cotton fabric.

[0049] (4) Weigh 0.85g of copper sulfate pentahydrate and 1.2g of sodium thiosulfate, add them to 200mL of distilled water, and sonicate for 0.5h to prepare a reaction solution. The concentration of copper sulfate pentahydrate in the reaction solution is 4.25g / L and the concentration of sodium thiosulfate is 6g / L.

[0050] (5) Use 0.1 ml of concentrated sulfuric acid to adjust the pH of the reaction solution to 2.

[0051] (6) Place the PANI cotton fabric in the reaction solution, shake at room temperature, and adjust the pH of the solution to 2 using concentrated sulfuric acid.

[0052] (7) The reaction solution used to soak the fabric was placed in a constant temperature water bath shaker for a stepwise heating and shaking reaction, which was carried out at 40℃ for 1 h, 60℃ for 1 h, and 80℃ for 0.5 h respectively. After the reaction, the cotton fabric was taken out, washed with distilled water until the washing solution was colorless, and dried at 60℃ to obtain Cu9S8 / PANI cotton fabric.

[0053] In this invention, the cotton fabrics are weighed before and after finishing, and the weight gain rate (WGR) of the cotton fabrics is calculated using the following formula (1).

[0054] WGR=(W2-W1)÷W1×100% Equation (1);

[0055] In the formula: W1—weight of cotton fabric, g; W2—weight of finished cotton fabric, g.

[0056] Figure 1 SEM images of PANI cotton fabric (a–c) and Cu9S8 / PANI cotton fabric (d–f) are shown. Figure 1 As seen in (a–c), the surface of the fibers coated with PANI becomes rough, forming a continuous and dense granular conductive layer. This indicates that PANI has successfully polymerized in situ and been uniformly deposited on the surface of the cotton fibers, constructing a stable conductive pathway. Meanwhile... Figure 1 In (d–f), after a stepped heating water bath treatment, a large number of structurally complete and uniformly distributed flower-like microspheres grew on the fiber surface. The formation of this structure is mainly attributed to the aggregation of copper ions under the coordination of nitrogen functional groups on the PANI surface, which further self-assembles and crystallizes as the temperature gradually increases, eventually forming a layered flower-like cluster structure.

[0057] This hierarchical structure not only significantly increases the roughness of the fiber surface, but also helps to build an efficient conductive network, thereby enhancing the conductivity and electromagnetic shielding capabilities of the fabric.

[0058] Figure 2 The XRD patterns of cotton fabric, PANI / cotton fabric, and Cu9S8 / PANI cotton fabric are shown to analyze the crystal structure and composition of the composite materials. As can be seen from the figure, the cotton fabric exhibits four typical cellulose diffraction peaks at 2θ of 14.9°, 16.5°, 22.6°, and 33.8°, corresponding to the (101) cellulose I diffraction peaks, respectively. The diffraction patterns of the PANI cotton fabric on the (002) and (040) crystal planes are almost identical to those of the cotton fabric, showing no obvious shift or new characteristic peaks. This is because the polyaniline attached to the cotton fabric does not crystallize and maintains certain amorphous characteristics. However, the Cu9S8 / PANI cotton fabric composite material clearly shows multiple sharp diffraction peaks, indicating the successful introduction of well-crystallized Cu9S8 into the composite material. These diffraction peaks highly match the characteristic peak positions of Cu9S8 in the standard PDF card (PDF#36-0379). 2θ at 27.7°, 29.2°, 32.3°, 47.9°, and 52.9° corresponds to the (0021), (0022), (1013), (111), and (1116) crystal planes of the hexagonal Cu9S8 phase, further confirming the presence of Cu9S8 crystals. Furthermore, the characteristic peaks of the cotton fabric can still be observed in the composite fabric, indicating that the composite process did not completely obscure the structural information of the original substrate.

[0059] In summary, the XRD patterns confirm that Cu9S8 was successfully loaded onto the surface of PANI / cotton fabric, forming an inorganic-organic hybrid composite material, which provides a structural basis for further research on its electromagnetic shielding and conductivity properties.

[0060] To analyze the chemical structural changes and interactions among the components, FTIR analysis was performed on cotton fabric, PANI / cotton fabric, and Cu9S8 / PANI cotton fabric. Figure 3 As shown, the FTIR spectra of cotton fabrics are at 3340, 1641, 1429, 1055, and 895 cm⁻¹. -1 A characteristic absorption peak of cellulose appeared at 3340 cm⁻¹. -1 The strong absorption peak at / is attributed to the OH stretching vibration, while the peak at 1641 cm⁻¹ is attributed to the OH stretching vibration. -1 The absorption peak at 1429 cm⁻¹ corresponds to the OH bending vibration of adsorbed water, indicating the presence of hydroxyl groups. -1 The absorption peak at / corresponds to the bending vibration of aliphatic -CH2 in cellulose, while the significant peak at 1055 cm⁻¹ corresponds to the bending vibration of aliphatic -CH2 in cellulose. -1 The absorption peak at 895 cm⁻¹ originates from the deformation vibration of the COC pyranose ring, a characteristic peak of the cellulose polysaccharide structure. -1 The characteristic peak at / corresponds to the vibration of the β-1,4-glycosidic bond, and all three samples exhibit the typical structural characteristics of cotton cellulose.

[0061] The characteristic peak of polyaniline is at 1569 cm⁻¹ -1 / and 1489cm -1 At position / , corresponding to stretching vibrations of the quinone ring (Q) and the benzene ring (B), respectively, the presence of the oxidized state of the emerald green imine was confirmed. 1295cm -1The distinct characteristic peak at / corresponds to the CN stretching vibration of polyaniline. Furthermore, at 795 cm⁻¹... -1 The characteristic peak at / originates from the out-of-plane bending vibration of the CH group in the para-disubstituted benzene ring. This confirms the successful loading of polyaniline onto cotton fabric. A new characteristic peak appears at 469 cm⁻¹ in the FTIR spectrum of the Cu9S8 / PANI / cotton fabric, corresponding to the Cu-S stretching vibration in Cu9S8.

[0062] This confirms that PANI and Cu9S8 were successfully composited on a cotton fabric substrate, constructing an inorganic-organic hybrid composite material.

[0063] Example 2

[0064] The difference from Example 1 is that the amount of aniline used in step (2) is 1 mL, and the mass ratio of aniline to dichloromethane solution is 1:80.

[0065] Example 3

[0066] The difference from Example 1 is that the amount of aniline used in step (2) is 1.5 mL, and the mass ratio of aniline to dichloromethane solution is 1.5:80.

[0067] Example 4

[0068] The difference from Example 1 is that the amount of aniline used in step (2) is 2.5 mL, and the mass ratio of aniline to dichloromethane solution is 2.5:80.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that the amount of aniline used in step (2) is 3 mL, and the mass ratio of aniline to dichloromethane solution is 3:80.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that the amount of aniline used in step (2) is 3.5 mL, and the mass ratio of aniline to dichloromethane solution is 3.5:80.

[0073] Comparative Example 3

[0074] The difference from Example 1 is that the amount of aniline used in step (2) is 4 mL, and the mass ratio of aniline to dichloromethane solution is 4:80.

[0075] Figure 4The effect of aniline dosage on the weight gain of PANI cotton fabric and Cu9S8 / PANI cotton fabric was demonstrated. As the aniline dosage increased from 1.0 mL to 4.0 mL, the weight gain of both samples showed an increasing trend, indicating that the thickness of the polyaniline layer increases with increasing monomer dosage. The weight gain of Cu9S8 / PANI cotton fabric was higher than that of pure PANI cotton fabric, indicating that further deposition of Cu9S8 on the PANI surface effectively improved the fabric quality. When the aniline dosage exceeded 3.5 mL, the weight gain of PANI cotton fabric increased rapidly, while the increase in the weight gain of the Cu9S8 / PANI composite slowed down, possibly because the excessively thick PANI layer hindered the deposition of Cu9S8. 2+ The diffusion and deposition reactions affected the formation efficiency of Cu9S8. A comparison of conductivity trends showed that an aniline dosage of 2 ml yielded the best results, facilitating the synergistic construction of the conductive polymer and the inorganic phase, and improving the stability and functionality of the composite fabric.

[0076] Example 5

[0077] The difference from Example 1 is that the concentration of CuSO4·5H2O in step (4) is 3.75 g / L.

[0078] Example 6

[0079] The difference from Example 1 is that the concentration of CuSO4·5H2O in step (4) is 4.75 g / L.

[0080] Comparative Example 4

[0081] The difference from Example 1 is that the concentration of CuSO4·5H2O in step (4) is 2.75 g / L.

[0082] Comparative Example 5

[0083] The difference from Example 1 is that the concentration of CuSO4·5H2O in step (4) is 3.25 g / L.

[0084] Figure 5 The effect of CuSO4·5H2O concentration on the weight gain of Cu9S8 / PANI cotton fabric was demonstrated. As the CuSO4·5H2O concentration increased from 2.75 g / L to 4.25 g / L, the weight gain gradually increased, reaching a peak at 4.25 g / L (approximately 35.6%). Within this range, Cu... 2+ The polyurethane (Cu) concentrates on the fiber surface through coordination with nitrogen groups on the PANI surface, providing reaction sites for subsequent vulcanization. However, when the concentration is further increased to 4.75 g / L, the weight gain decreases slightly, possibly due to localized Cu concentrations. 2+Excessive concentration leads to uneven crystal structure or partial agglomeration and detachment, thus affecting the deposition quality of Cu9S8. Therefore, the highest weight gain rate is achieved when the CuSO4·5H2O concentration is 4.25 g / L.

[0085] Example 7

[0086] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 4.5 g / L.

[0087] Example 8

[0088] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 5 g / L.

[0089] Example 9

[0090] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 5.5 g / L.

[0091] Comparative Example 7

[0092] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 3.5 g / L.

[0093] Comparative Example 8

[0094] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 4 g / L.

[0095] Comparative Example 9

[0096] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 6.5 g / L.

[0097] Comparative Example 10

[0098] The difference from Example 1 is that the concentration of Na2S2O3 in step (4) is 7 g / L.

[0099] Figure 6 The effect of Na₂S₂O₃ concentration on the weight gain rate of Cu₉S₈ / PANI cotton fabric is shown. With increasing Na₂S₂O₃ concentration, the weight gain rate continuously increases, reaching a maximum of 40%, and then slightly decreases at higher concentrations. 2- The gradual increase promoted Cu 2+ It reacts with the sulfur source, promoting the formation and deposition of Cu9S8 crystals. However, when S... 2- Excessive sodium thiosulfate concentration may lead to an excessively rapid reaction rate or disordered crystal structure, thereby reducing the effective loading. Therefore, a sodium thiosulfate concentration of 6.0 g / L results in the best electrical conductivity, facilitating the uniform deposition of Cu9S8 on the conductive polymer surface and providing a foundation for improving the electrical properties and structural stability of the composite material.

[0100] Figure 7 The conductivity of PANI cotton fabric and Cu9S8 / PANI cotton fabric prepared with varying aniline dosages is shown in the figure. As can be seen from the figure, overall, the conductivity of Cu9S8 / PANI cotton fabric is significantly improved compared to PANI cotton fabric. With increasing aniline dosage, the conductivity of the fabric increases significantly. When the aniline dosage is 2 ml, the conductivity of Cu9S8 / PANI cotton fabric reaches a peak of 6.2 S / cm. Simultaneously, the surface resistance decreases with increasing aniline dosage, reaching its lowest point at 2 ml, and then slightly recovers. This may be related to the unevenness or structural defects of the PANI layer caused by excessive aniline. Therefore, the aniline dosage has a significant impact on conductivity. An appropriate dosage not only helps to form a continuous conductive path but also avoids performance degradation caused by uneven polymerization. In summary, the optimal conductivity is obtained with an aniline dosage of 2 ml.

[0101] Figure 8 The electrical conductivity of Cu9S8 / PANI cotton fabrics prepared with CuSO4·5H2O concentrations was demonstrated. Experimental results show that the fabric conductivity significantly increases when the CuSO4·5H2O concentration is between 2.50 and 3.75 g / L. This is mainly due to the increasing concentration of CuSO4·5H2O. 2+ With SO4 2- As the concentration increases, the number of migratable ions in the system increases, enhancing charge conduction. The conductivity improves significantly at this stage, demonstrating the dominant conduction behavior of CuSO4·5H2O in the system. Subsequently, with continued increase in CuSO4·5H2O concentration, the upward trend in conductivity slows and stabilizes, indicating that the system is gradually approaching ion saturation. The conductivity of the Cu9S8 / PANI cotton fabric reaches its peak of 6.2 S / cm at a concentration of 4.25 g / L. Subsequently, the conductivity of the Cu9S8 / PANI cotton fabric begins to decrease when the concentration reaches 4.75 g / L, possibly due to excess Cu. 2+ Local aggregation occurred in the Cu9S8 / PANI layer, limiting its further conductivity. Simultaneously, resistivity and conductivity exhibited an inverse relationship, rapidly decreasing in the 2.75–3.75 g / L range, then stabilizing, with a slight rebound at 4.75 g / L, consistent with the conductivity performance shown by conductivity. Therefore, the Cu9S8 / PANI cotton fabric exhibits optimal conductivity when the CuSO4·5H2O concentration is 4.25 g / L.

[0102] Figure 9The effect of Na₂S₂O₃ concentration on the electrical conductivity of PANI cotton fabric and Cu9S₈ / PANI cotton fabric was investigated. As the Na₂S₂O₃ concentration increased from 3.5 g / L to 6.0 g / L, the conductivity rapidly increased from 0.05 S / cm to a peak of 8.6 S / cm, and then began to decrease with further concentration increases. This trend indicates that at lower concentrations, the sulfur source is insufficient to completely sulfide copper ions to form the Cu9S₈ structure, and may even disrupt the original conductivity of the PANI layer. However, at a Na₂S₂O₃ concentration of 6 g / L, the conductivity improved significantly with increasing concentration of Cu9S₈ / PANI. 2+ A complete reaction is beneficial for the formation of a continuous conductive network of grains. Excess sodium thiosulfate may lead to side reactions, thereby reducing the overall conductivity. The corresponding surface resistivity also shows a trend of first decreasing and then slightly increasing, reaching a minimum of 0.116 Ω·cm near 6.0 g / L, which is consistent with the conductivity trend. Therefore, the conductivity is optimal when the Na2S2O3 concentration is controlled at 6.0 g / L.

[0103] Figure 10 The effect of aniline dosage on the electromagnetic shielding effectiveness of Cu9S8 / PANI cotton fabric was demonstrated. As the aniline dosage increased from 1 mL to 2 mL, the shielding effectiveness gradually improved, reaching its optimal level at 2 mL. Figure 7 The conductivity trend was consistent, with an SE value of 24.5 dB, indicating that an appropriate amount of aniline helps Cu9S8 to form uniformly on the PANI conductive network, improving the material's conductivity and enhancing its reflectivity. However, when the amount of aniline continued to increase to 3 mL or more, the shielding effectiveness decreased, with the SE value dropping below 15 dB. This may be because excessive aniline led to an overly thick PANI coating layer, causing uneven agglomeration of Cu9S8, resulting in a discontinuous conductive network and hindering electron migration and interfacial polarization effects. Therefore, the electromagnetic shielding effectiveness was optimal when the amount of aniline was 2 mL.

[0104] Figure 11 The effect of CuSO4·5H2O concentration on the electromagnetic shielding effectiveness of Cu9S8 / PANI cotton fabric was investigated. As the CuSO4·5H2O concentration increased from 2.75 g / L to 4.25 g / L, the shielding effectiveness significantly improved. At a concentration of 4.25 g / L, the Cu9S8 / PANI cotton fabric exhibited the highest SE value, reaching 28.9 dB. A certain concentration of CuSO4·5H2O... 2+ This facilitates the full deposition and uniform dispersion of Cu9S8 crystals on the PANI layer, enhancing the conductivity and multi-interface polarization loss effect of the composite material. However, when the CuSO4·5H2O concentration further increases to 4.75 g / L, the shielding effectiveness shows a decreasing trend. Figure 8The conductivity trend is consistent, with the SE value decreasing to around 25 dB. This is presumably due to Cu9S8 agglomeration caused by copper ion supersaturation, which disrupts the continuity of the conductive network. Therefore, 4.25 g / L is the optimal concentration of CuSO4·5H2O.

[0105] Figure 12 The effect of Na₂S₂O₃ concentration on the electromagnetic shielding effectiveness of Cu9S₈ / PANI cotton fabric was investigated. As the Na₂S₂O₃ concentration increased from 3.5 g / L to 6 g / L, the shielding effectiveness steadily improved. At a concentration of 6 g / L, the SE value of the Cu9S₈ / PANI cotton fabric reached a maximum of 28.9 dB, exhibiting excellent shielding performance. This indicates that an appropriate amount of sulfur source contributes to the sufficient growth and uniform coverage of Cu9S₈ crystals, forming a good conductive network and interfacial polarization structure. However, as the concentration continued to increase, the shielding effectiveness tended to saturate and even slightly decreased, possibly due to the precipitation of sulfur from excessive sulfur source, leading to a reduction in the density of the Cu9S₈ structure. Therefore, 6 g / L is the optimal value for the amount of sulfur source.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing Cu9S8 / PANI cotton fabric, characterized in that: include, Aniline is dissolved in dichloromethane solution to obtain an organic phase solution; Ammonium persulfate and sodium sulfosalicylate were added to distilled water and sonicated to obtain an aqueous solution. The cotton fabric was ultrasonically washed with deionized water and anhydrous ethanol, dried, weighed, soaked in an organic phase solution, placed in a refrigerator, and an aqueous phase solution was added dropwise. The reaction was sealed to obtain a dark green cotton fabric. After washing with distilled water until colorless, the fabric was dried to obtain PANI cotton fabric. Copper sulfate pentahydrate and sodium thiosulfate were added to distilled water and sonicated to obtain a reaction solution. The pH of the reaction solution was adjusted with concentrated sulfuric acid. The PANI cotton fabric was placed in the reaction solution and shaken at room temperature. Then, the reaction was carried out by stepwise heating and shaking. After the reaction, the cotton fabric was taken out, washed with distilled water until colorless, and dried to obtain Cu9S8 / PANI cotton fabric.

2. The preparation method according to claim 1, characterized in that: The mass ratio of aniline to dichloromethane solution in the organic phase solution is 1–4:

80.

3. The preparation method according to claim 1, characterized in that: The molar ratio of ammonium persulfate to sodium sulfosalicylate in the aqueous solution is 1:1 to 1:

2.

4. The preparation method according to claim 1, characterized in that: The concentration of copper sulfate pentahydrate is 3.75–4.75 g / L.

5. The preparation method according to claim 1, characterized in that: The concentration of sodium thiosulfate is 4.5–5.5 g / L.

6. The preparation method according to claim 1, characterized in that: The concentrated sulfuric acid is used to adjust the pH of the reaction solution to 2-3.

7. The preparation method according to claim 1, characterized in that: The stepped heating and oscillating reaction is carried out at 40-50℃ for 1 hour, 60-70℃ for 1 hour, and 80-90℃ for 0.5 hours.

8. The preparation method according to claim 6, characterized in that: The concentrated sulfuric acid was used to adjust the pH of the reaction solution to 2.

9. Cu9S8 / PANI cotton fabric prepared by the method described in claims 1 to 8.

10. The application of the Cu9S8 / PANI cotton fabric as described in claim 9 in conductive fabrics and electromagnetic shielding fabrics.

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