Multifunctional MXene-based composite film with synchronous laser reduction and micro-nano structure regulation

Abstract

The invention discloses a graphene oxide / MXene-carbon fiber hierarchical composite film based on laser synchronous reduction and micro-nano structure regulation and a preparation method of the graphene oxide / MXene-carbon fiber hierarchical composite film. The method comprises the following three steps: (1) etching a Ti3AlC2MAX phase by adopting HCl / HF-LiCl to prepare a single-layer MXene colloidal solution; (2) sequentially depositing an MXene layer and a graphene oxide (GO) layer on a commercial carbon fiber substrate (the surface density is 10g / m < 2 >) through a vacuum-assisted suction filtration technology, and performing vacuum drying to form a precursor; and (3) performing selective area irradiation on the precursor by using an Nd: YAG laser, synchronously realizing GO reduction and microstructure regulation and control, and finally obtaining the reduced graphene oxide (rGO) / MXene-carbon fiber hierarchical composite film. The film has the anti-oxidation-electric conduction-mechanical cross-scale synergistic characteristic, and shows excellent photo-thermal / electro-thermal conversion, super-hydrophobicity, electromagnetic shielding and other multifunctional integration performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of composite functional materials, in particular to a graphene / MXene-carbon fiber hierarchical composite material prepared by using laser reduction of graphene oxide (GO) + laser micro / nano structure regulation technology. The composite material realizes active / passive efficient deicing and electromagnetic wave shielding (≥110 dB, 8.2-12.8 GHz) in a low-temperature environment through the synergistic effect of photothermal-thermal multi-modal response and surface super-hydrophobicity. It can be applied to aerospace skin, polar equipment, high-voltage transmission lines and 5G communication equipment in extreme environment scenarios. BACKGROUND

[0002] With the rapid development of the fifth generation wireless communication system (5G), autonomous aerospace vehicles, polar exploration and new energy infrastructure, the demand for high-performance materials with efficient deicing and anti-icing and electromagnetic shielding (EMS) functions has greatly increased. Developing new multifunctional materials with efficient electromagnetic shielding (EMS) and all-weather self-deicing / anti-icing capabilities has become a frontier challenge in the field of materials science. Two-dimensional transition metal carbide / nitride represented by MXene (such as Ti3C2T n ) is considered a potential candidate for EMS and active deicing due to its ultra-high intrinsic conductivity (>10,000 S / cm), controllable surface functional groups (-O, -F) and excellent electro-thermal response characteristics. However, due to its inherent defects, such as poor environmental stability (easy oxidation in humid / high temperature environments) and mechanical brittleness (fracture strain <3%), MXene faces serious challenges in practical applications. These multiple challenges highlight an urgent scientific need to develop a multifunctional material that can integrate all-weather deicing / anti-icing capabilities and high-performance electromagnetic shielding performance. Existing technical bottlenecks and analysis: To overcome the above-mentioned defects, existing technologies mainly adopt single performance optimization strategies, such as CN202210025962.7, which improves the environmental stability of MXene by coating a starch polymer layer on the surface of MXene. However, this method usually sacrifices the high conductivity and electro-thermal conversion efficiency of the material, which is not conducive to EMS and efficient deicing. The MXene / silver nanowire composite material developed by patent CN111132533B and the MXene aerogel / epoxy resin composite material developed by patent CN109897343B only optimize the EMS performance and do not involve deicing function; patent CN118772784A focuses on low-temperature deicing coatings. Therefore, traditional single performance optimization strategies (such as surface passivation and polymer composite) can alleviate some contradictions, but it is difficult to break the mutual exclusion barrier of "conductivity-stability-mechanical strength", which seriously hinders its application in complex working conditions SUMMARY

[0003] Based on the inherent defects (poor environmental stability, mechanical brittleness) of the MXene material described in the background art and the limitations of the traditional single performance optimization strategy, the present application provides a graphene / MXene-carbon fiber hierarchical composite film based on laser synchronous reduction and micro-nano structure regulation and a preparation method thereof. The functional material realizes a cross-scale synergistic mechanism of "oxidation resistance-conduction-mechanics", as well as superior photo-thermal-electric, surface super-hydrophobic and electromagnetic shielding multi-modal response performance.

[0004] The present application solves the above specific problems by the following technical solutions:

[0005] The first object of the present application is to provide a graphene / MXene-carbon fiber hierarchical composite film, which is designed by hierarchical structure and comprises: a first layer (substrate): a surface density of 10 g / m 2 The carbon fiber film serves as a mechanical bearing framework, giving the film high strength and high modulus; the second layer (intermediate functional layer): the MXene colloidal solution and the carbon fiber are interwoven together with the aid of vacuum filtration, and the carbon fiber and MXene composite material combines the advantages of both, having high strength, high conductivity and high thermal conductivity. The problem of mismatch between the electric-thermal / photothermal response and the mechanical properties (fracture strain <3%) of MXene is solved; the third layer (surface functional layer): graphene oxide (GO) is an oxidation-resistant sacrificial layer, which realizes in-situ reduction (GO→rGO) and surface micro-nano structure construction through laser irradiation, improving the stability of the conductive network and the multi-modal response ability.

[0006] The second object of the present application is to provide a preparation method of the above graphene / MXene-carbon fiber hierarchical composite film, comprising the following three preparation process steps:

[0007] The first process step of the above preparation method of the graphene / MXene-carbon fiber hierarchical composite film provided by the present application is as follows:

[0008] MXene colloidal solution preparation: etching MAX phase with HCl / HF (HF content 40%, HCl 65%), etching at 30-45 DEG C for 10-16 hours to ensure complete removal of Al layer in MAX phase;

[0009] Further, the above etched mixed liquid is centrifuged and washed to neutral, and Licl solution is used as an intercalating agent, and centrifugal stirring is carried out at 30-45 DEG C for 10-16 hours;

[0010] Further, ultrasonic peeling control: 400W ultrasonic treatment for 25 minutes to obtain a single-layer MXene colloidal solution (lateral size 0.5-2 microns), and then vacuum filtration of 10ml MXene colloidal solution is carried out to obtain the mass, and finally the concentration of MXene is obtained.

[0011] Further, the concentration of the single-layer MXene colloidal solution is 1-5 mg / ml.

[0012] The second process step of the preparation method of the graphene / MXene-carbon fiber hierarchical composite film provided by the application is as follows:

[0013] The hierarchical film is formed layer by layer: first, MXene is filtered onto the carbon fiber with the aid of vacuum, the concentration of the MXene solution is 1-5 mol / L, after no filtrate is left, the filtered GO solution is further used as the functional layer on the top, the concentration of the GO solution is 1-5 mol / L, and vacuum drying (40-50℃) is performed for 1-2 hours after the above step is completed.

[0014] The third process step of the preparation method of the graphene / MXene-carbon fiber hierarchical composite film provided by the application is as follows:

[0015] Laser in-situ reduction and micro-nano structure regulation: the GO / MXene-carbon fiber precursor film is treated by using a Nd:YAG laser, the energy density is 0.4-3 J / cm 2 , the frequency is 1-10 Hz, and GO is locally carbonized and reduced;

[0016] Periodic micropore arrays (pore diameter 5-20 μm) and surface wrinkle structures are formed by scanning through a 5-axis displacement platform (speed 5-20 mm / s), and hydrophobicity (contact angle ≥ 134°) is given.

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] The application provides a rGO / MXene-carbon fiber hierarchical composite film based on laser synchronous reduction and micro-nano structure regulation, the functional material realizes a synergistic mechanism of "oxidation resistance-conduction-mechanics", the MXene colloidal solution and the carbon fiber are interwoven together with the aid of vacuum filtration, the composite material of the carbon fiber and the MXene combines the advantages of both, and has the performances of high strength, high conductivity and high thermal conductivity. The mechanical strength is increased from 25 MPa to 67 MPa, which is more than 2 times that of a single MXene film.

[0019] The application provides a composite film with efficient environmental stability, active deicing and electromagnetic shielding. In view of the mutual exclusion problem of high conductivity and environmental instability of MXene, graphene oxide is reduced by laser to prevent MXene from directly contacting air or a humid environment, the chemical stability is improved, the corrosion potential is increased from-0.2 V (pure MXene) to +0.18 V, the corrosion potential is changed from a negative value to a positive value. After 90 days of humidity aging, the corrosion potential (0.15 V) is still positive.

[0020] The present application provides a rGO / MXene-carbon fiber hierarchical composite film with super-hydrophobic passive anti-icing and electro-thermal / photothermal active deicing multifunction. By laser in-situ reduction of the upper GO functional layer, micro-nano structure processing is realized, and the surface presents micro-nano porous structure and wrinkles, which provides favorable conditions for surface hydrophobicity. Its super-hydrophobic structure can prolong the icing time and reduce the adhesion force of ice bonding. Compared with the icing time of pure MXene (206 seconds), the icing of rGO / MXene-carbon fiber hierarchical composite film (356 seconds) is prolonged by 1.7 times, in addition, and the rapid response of photothermal / electrothermal under extreme low temperature conditions improves the deicing efficiency, compared with single MXene film, the photothermal / electrothermal response rate is fast, and the cycle stability is good, under a simulated light condition, the photothermal conversion temperature is 120℃, under the same conditions, it is increased by 90℃ compared with pure MXene (29℃). Under the voltage of 2V, the surface temperature of rGO / MXene-carbon fiber hierarchical composite film is about 90℃, under the same conditions, it is increased by 20℃ compared with pure MXene (70℃), and the photothermal / electrothermal improves the efficiency of deicing.

[0021] The present application provides a rGO / MXene-carbon fiber hierarchical composite film with high electromagnetic shielding performance (EMS): the shielding effectiveness of the film in X band (8.2-12.4GHz) is ≥110dB, which is better than that of pure MXene film (~80dB). BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 . TEM image of single-layer MXene.

[0023] Figure 2 . Structure characterization of composite film. XRD patterns of MXene, GO, CF and GO / MX@CF-P / rGO / MX@CF-L1 / L2 / L5 / L10 films, showing the phase evolution during laser processing.

[0024] Figure 3 . Raman spectrum of laser reduction.

[0025] Figure 4 . Water contact angle measurement of GO / MX@CF-P and rGO / MX@CF-L1 / L2 / L5 / L10, showing laser-induced hydrophobicity evolution (droplet volume is 3μL, n=5 repeated).

[0026] Figure 5Morphology evolution characterization of laser processing composite materials. (a-e) Laser confocal microscopy images show the surface morphology evolution of rGO / MX@CF thin films: (a) precursor (P), (b) L1, (c) L2, (d) L5, and (e) L10 laser treated samples, the suffix number represents the laser frequency. (f) Height profile plots along the corresponding dashed lines in (a-e), surface roughness modulation is quantified by laser parameter optimization.

[0027] Figure 6 Photothermal performance characterization. Equilibrium temperature infrared thermography of GO / MX@CF-P, rGO / MX@CF-L1, rGO / MX@CF-L2, rGO / MX@CF-L5, and rGO / MX@CF-L10 under 0.5, 1.0, and 2.0 sun irradiation.

[0028] Figure 7 Electrical conductivity performance characterization. The resistance values of GO, T3C2Tx, GO / MX@CF-P, and rGO / MX@CF-L1, L2, L5, L10 samples after different frequency laser treatment are shown.

[0029] Figure 8 Electrocaloric performance characterization. Infrared thermography and average surface temperature distribution of GO, Ti3C2Tx, GO / MX@CF-P, and rGO / MX@CF-L2 under 2 V applied voltage for 180 seconds.

[0030] Figure 9 Stability test. Tafel curves of MXene, rGO / MX@CF-L2, and 90-day aged rGO / MX@CF-L2.

[0031] Figure 10 Mechanical strength. Stress-strain curves of rGO / MX@CF-L2, MXene, and GO.

[0032] Figure 11 Anti-icing performance. (a) Delayed icing process of MXene, GO / MX@CF-P, and rGO / MX@CF-L2 surfaces at -15 °C. (b) Ice delay time of water droplets on MXene, GO / MX@CF-P, and rGO / MX@CF-L2 surfaces.

[0033] Figure 12 Electromagnetic shielding performance test of pure MXene film and rGO / MXene@CF-L2 film

[0034] Figure 13 Schematic diagram of MXene-based composite materials for all-weather anti-icing and deicing and electromagnetic shielding DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0036] Embodiment 1: basic embodiment

[0037] Step 1: preparation of single-layer MXene colloidal solution

[0038] (1) 20 ml of 40% HF solution and 25 ml of 65% HCl solution were measured in a polytetrafluoroethylene reaction tank, and the mixture was stirred magnetically for 15 minutes

[0039] (2) 2.0 g of Ti3AlC2 MAX phase powder (400 mesh) was weighed and then added to the mixed acid, and the reaction temperature was controlled at 35±1℃

[0040] (3) After stirring for 12 hours under nitrogen protection, centrifugal separation was performed at 2500 r / min, and washing was performed with deionized water until pH=6.8

[0041] (4) 2.0 g of LiCl was dissolved in 20 ml of deionized water, and after mixing with the etching product, ultrasonic exfoliation was performed in a 40℃ water bath for 18 hours

[0042] (5) After 5 times of centrifugation (3000 r / min x 10 min), treatment was performed in a 450W ultrasonic cleaning machine for 25 minutes

[0043] (6) The colloidal concentration was measured by vacuum filtration method to be 19 mg / mL, and deionized water was used to dilute it to 1.0 mg / mL; 2.0 mg / mL; 3.0 mg / mL; 4.0 mg / mL; 5.0 mg / mL for standby

[0044] Step 2: preparation of precursor film

[0045] (1) A commercial carbon fiber substrate (porosity 15%) with an areal density of 10 g / m 2 was fixed in a vacuum filtration device (pore size 0.45um PTFE membrane)

[0046] (2) 20 ml of MXene colloidal solution (5.0 mg / mL) was filtered, and the vacuum drying conditions were 60℃ x 2h, and the vacuum degree was ≤10Pa

[0047] (3) Continue to filter 10 ml of GO solution (5.0 mg / mL), and the drying conditions are 45℃ x 2h

[0048] (4) Obtain GO / MXene-carbon fiber precursor film (thickness 130±5 μm)

[0049] Step 3: Laser synchronous reduction and structure regulation

[0050] (1) Place the precursor film in the laser processing cavity, vacuum to 0.9 MPa, then fill nitrogen to normal pressure

[0051] (2) Set the Nd:YAG laser parameters: wavelength 532 nm, energy density 3 J / cm 2 , frequency 1 Hz, spot diameter 500 μm (after focusing)

[0052] (3) Use a five-axis platform for spiral scanning (linear velocity 8 mm / s, spot overlap rate 30%)

[0053] (4) Obtain rGO / MXene-carbon fiber composite film (surface contact angle 126°, sheet resistance 15 Ω / sq

[0054] Adjust the laser parameters in step (3) based on Example 1:

[0055] The laser parameters are optimized by orthogonal experiment, in which the laser power is 0.8, 0.8, 1.6, 3 J / cm 2 , and the laser frequency is 1, 2, 5, 10 Hz. The other parameters of the Nd:YAG laser remain unchanged, and the other experimental conditions remain the same as in Example 1.

[0056] Table 1. Laser parameter optimization experiment

[0057]

[0058] When the energy density = 1.6 J / cm 2 , and the frequency = 2 Hz (A10 group), Figure 6 the sheet resistance (132 Ω / sq) and Figure 3 hydrophobicity (contact angle 134.54°) reach the optimal balance, and are selected as the best parameters.

[0059] The above examples are only used to illustrate the technical solutions of the present application and are not limiting. Those skilled in the art should understand that any equivalent replacement or adaptive modification based on the essential principles of the present application (such as laser parameter adjustment, carbon fiber substrate density change, MXene / GO concentration optimization, etc.) should be included within the protection scope of the present patent, as long as it does not deviate from the technical solutions defined in the claims of the present application.

Claims

1. A method for preparing a graphene / MXene-carbon fiber layered composite film combining laser synchronous reduction and micro / nano structure modulation, characterized in that, The preparation method is as follows: Step 1. Preparation of a monolayer MXene colloidal solution: Mix 15-35 ml of 40% HF and 20-30 ml of 65% HCl to etch 1.5-2.5 g of Ti3AlC2 powder; stir in a water bath at 35°C for 10-15 h; centrifuge and wash until neutral; add LiCl intercalating agent and stir at 30-45°C for 10-20 h; sonicate at 400 W for 20-30 min. Step 2. Hierarchical Assembly: With a surface density of 10 g / m³ 2 On a carbon fiber substrate, MXene solution (1-5 mg / mL) and GO solution (1-5 mg / mL) were sequentially vacuum filtered; the substrate was then vacuum dried at 40-80℃ for 1-3 h to obtain GO / MXene-carbon fiber precursor. Step 3. Laser Synchronous Reduction and Micro / Nano Control: The precursor was placed in a nitrogen-protected chamber; selective irradiation was performed using a 532nm wavelength Nd:YAG laser with an energy density of 0.4-3 J / cm³. 2 The frequency is 1-10Hz and the spot diameter is 300-600μm. The periodic micropore array (pore diameter 5-20μm) and surface wrinkle structure are formed by scanning at 5-20mm / s through a 5-axis displacement platform.

2. The preparation method according to claim 1, characterized in that, In step (1), the monolayer MXene colloidal solution is prepared by the following method: (1) Measure 15-35 ml of 40% HF and 20-30 ml of 65% HCl and pour them into a polytetrafluoroethylene container and mix well; (2) 1.5-2.5g of Ti3AlC2 MAX phase powder was slowly added to the mixed acid in step (1), and the mixture was heated in a water bath at 35°C and magnetically stirred for 10-15 hours. (3) After etching with mixed acid HCl / HF in step (2), centrifuge at 1000-3000r / min and wash repeatedly until it becomes neutral; (4) Dissolve 1-3g of lithium chloride (LiCl) in 15-30ml of deionized water in a polytetrafluoroethylene container. Mix the resulting LiCl solution with the neutralized powder washed in step (3) in a water bath at 30-45℃ and stir magnetically for 10-20 hours. (5) After centrifuging the etched solution in step (4) 5-9 times, ultrasonically treat it in an ultrasonic cleaner with a power of more than 400W for 20-30 minutes. (6) Take 10 ml of the monolayer MXene colloidal solution from step (5), filter and dry it under vacuum, weigh the mass of the obtained MXene filter membrane, and then calculate the concentration of the monolayer MXene colloidal solution. (7) Prepare a 1-5 g / ml monolayer MXene colloidal solution based on the concentration of the monolayer MXene colloidal solution known in step (6).

3. The preparation method according to claim 1, characterized in that, In step (2), the GO / MXene-carbon fiber precursor film is prepared by sequential filtration using vacuum-assisted technology. The preparation method is as follows: (1) Take 20 ml of monolayer MXene colloidal solutions of different concentrations (1-5 mg / ml), and use vacuum-assisted filtration technology to embed the MXene colloidal solutions of different concentrations into commercially available carbon fibers (area density 10 g / m²). 2 On the surface, MXene-carbon fiber membranes with different concentrations were obtained; (2) Pour the GO solution into the top layer of the MXene-carbon fiber membrane obtained in (1) and filter it. After there is no obvious filtrate, dry it in a drying oven at 40-50℃ for 1-2 hours to finally obtain the GO / MXene-carbon fiber precursor film.

4. The preparation method according to claim 1, characterized in that, In step (3), the method uses an Nd:YAG laser (532nm) to process the GO / MXene-carbon fiber precursor film, and the preparation method is as follows: (1) Place the GO / MXene-carbon fiber precursor film horizontally in the laser ablation cavity, evacuate the vacuum equipment to 0.9 MPa, and then fill it with nitrogen to atmospheric pressure as a protective gas. (2) Adjust the parameters of the Nd:YAG laser (532nm) to achieve a laser energy of 0.4-3 J / cm². 2 The laser frequency is 1-10Hz; (3) Then the laser ablation chamber containing the sample in (1) is placed on a 5-axis displacement platform. The displacement path and speed are controlled by setting a program so that the laser can uniformly process the GO / MXene-carbon fiber precursor film and obtain rGO / MXene-carbon fiber layered composite film after laser ablation.

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