Super-hydrophobic polyester fabric and preparation method thereof

Abstract

The invention discloses a super-hydrophobic polyester fabric and a preparation method thereof, and relates to the technical field of polyester fabrics. According to the super-hydrophobic polyester fabric and the preparation method thereof, polyester fibers are used as a fabric base material, the adhesive force of the fabric base material is enhanced and the specific roughness is constructed through pretreatment, gallium-indium alloy is used as a liquid metal raw material, and a liquid metal microdroplet suspension matched with a pretreated fabric base is prepared; metal microdroplet suspension liquid is directionally deposited on a pretreated substrate based on electric field force to form a discrete structure, and a Ga2O3 passive film is formed on the surface of the metal microdroplet suspension liquid according to controllable oxidation generation. A polydopamine coating is formed on the surface of polyester through dopamine pretreatment, a catechol group in molecules of the polydopamine coating and a hydroxyl group on the surface of polyester fiber can form a covalent bond and a hydrogen bond, a stable anchor point is provided for subsequent liquid metal microdroplets, and the problem that a traditional coating falls off due to physical adsorption is solved; the durability of the hydrophobic structure is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of polyester fabric technology, specifically to a superhydrophobic polyester fabric and its preparation method. Background Technology

[0002] Superhydrophobic polyester fabrics are in high demand in outdoor products, medical protective equipment, and industrial filter materials due to their stain-resistant and self-cleaning properties. Existing technologies for imparting superhydrophobicity to polyester mainly include surface coating, chemical grafting, and physical etching.

[0003] Surface coating methods often involve coating with fluorinated compounds or silicone resins to create a hydrophobic layer. However, the bonding between the coating and polyester fibers largely depends on physical adsorption, which can easily detach due to friction or washing, leading to a rapid decline in hydrophobic properties. Chemical grafting introduces hydrophobic groups onto the fiber surface through chemical reactions. Although the bonding force is strong, the reaction conditions are harsh, resulting in high energy consumption and potential damage to the fiber's mechanical properties. Furthermore, the process is complex and difficult to scale up. Physical etching can improve hydrophobicity by creating a rough surface, but the lack of low surface energy materials for modification in a single physical structure leads to insufficient hydrophobic stability. Moreover, the etching depth is difficult to control, which can cause the fabric to feel stiff.

[0004] Furthermore, most functional materials used to construct hydrophobic structures in existing technologies are artificially synthesized, and some fluorinated materials pose a risk of bioaccumulation, requiring improvement in environmental friendliness. Simultaneously, controlling the uniformity of micro / nano structures is a key challenge; structural inhomogeneity leads to large fluctuations in hydrophobic properties, making it difficult to meet the stability requirements of practical applications. Therefore, developing a simple, strong, durable, and environmentally friendly method for preparing superhydrophobic polyester fabrics has become an urgent problem to be solved by the industry. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a superhydrophobic polyester fabric and its preparation method, thus solving the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a superhydrophobic polyester fabric and its preparation method, the method comprising: using polyester fiber as the fabric substrate, and pre-treating it to enhance the adhesion of the fabric substrate and construct a specific roughness; using gallium-indium alloy as a liquid metal raw material to prepare a liquid metal microdroplet suspension that matches the pre-treated fabric substrate; directionally depositing the metal microdroplet suspension onto the pre-treated substrate based on an electric field to form a discrete structure; and forming a Ga2O3 passivation film on the surface of the metal microdroplet suspension through controllable oxidation; and further comprising the following sub-steps:

[0007] S101. Using the diameter of polyester fiber as the screening condition for fabric substrate, a buffer solution of Tris-HCl and dopamine is prepared. The fabric substrate and the buffer solution are polymerized and a dopamine layer is formed on the fabric substrate.

[0008] S102. After melting a gallium-indium alloy, drop it into the prepared SDS solution and disperse it ultrasonically to form a metal droplet suspension.

[0009] S103. The fabric substrate is stretched and clamped by a clamp, and the fabric and platinum sheet are placed in the electrolytic cell and injected with the obtained metal microdroplet suspension to obtain the precipitated fabric substrate.

[0010] S104. The precipitated fabric substrate is subjected to oxidation to form a Ga2O3 passivation film, which is then subjected to oxide film detection and performance testing.

[0011] A further improvement to the technical solution of the present invention is that the polyester fiber as the base material further includes the following configuration:

[0012] Polyester fibers have a diameter of 15-20μm and a contact angle of ≤70°.

[0013] No fiber breakage or impurity particles.

[0014] Furthermore, controlling the fiber diameter deviation within 5μm ensures that the subsequent coating thickness fluctuation is ≤3nm; the contact angle is ≤70° to ensure that the polydopamine solution spreads at a rate ≥2mm / s on the fabric surface, avoiding local drying, and eliminating defective fabrics can reduce the coating defect rate.

[0015] A further improvement of the technical solution of the present invention is that: the pretreatment to enhance the adhesion of the fabric substrate and to construct a specific roughness further includes: placing the fabric substrate in a cleaning tank and completely immersing it in deionized water, with the liquid level 2-5 cm above the fabric substrate, cleaning it with an ultrasonic cleaning device for 10-15 minutes and then changing the water, repeating the operation 1-3 times.

[0016] Pipette deionized water into a beaker, place a 30-40 mm stir bar inside, and set the stirring speed to 100-300 r / min. Weigh Tris powder and pour it into the beaker, stirring until completely dissolved. Add 1 mol / L HCl dropwise to adjust the pH to 8.5 ± 0.1. Pipette Tris-HCl buffer into a container, add dopamine hydrochloride, and magnetically stir at 200-600 r / min until completely dissolved, yielding a light pink solution.

[0017] A further improvement to the technical solution of the present invention is that it also includes:

[0018] Use tweezers to pick up the ultrasonically cleaned fabric substrate, unfold it and hang it with a quartz hook 1cm from the top of the fabric, and gradually place it in a light pink solution with the liquid level 1-2cm above the fabric.

[0019] Tighten the container lid and start timing. Every 30 minutes, gently tap the fabric with a quartz rod, touching it from the edge to avoid scratching it. Observe the color change of the solution. It will turn light brown after 20 minutes and dark brown after 2 hours, which means the reaction is over.

[0020] Lift the fabric with a hook, let it drain over the container for 10-30 seconds, then lay it flat on a quartz tray and place it in the middle layer of the oven. Set the temperature to 40-60℃ and the wind speed to 1-1.5m / s. Dopamine forms a coating on the fabric substrate. Dopamine polymerizes evenly on the fabric surface to form a continuous and firmly bonded coating.

[0021] To ensure that the coating thickness and roughness meet the requirements and to provide an ideal substrate for microdroplet adhesion, the following are also included:

[0022] After drying, the fabric substrate was cooled to 25°C and tested with an MS-70 moisture meter. The probe was inserted into the fabric at 3 points, and the average value was taken to ensure that the moisture content was ≤1%. The probe of the step meter lightly touched the edge of the fabric, that is, the junction between the coating and the uncoated area, and scanned along the horizontal direction to measure 10 lines and take the average thickness. The AFM scanned a 5×5μm area in tapping mode to analyze the surface roughness Ra.

[0023] A further improvement to the technical solution of the present invention is that the use of gallium-indium alloy as a liquid metal raw material includes the following configuration:

[0024] Gallium and indium blocks were added to the crucible at a mass ratio of 7:3. The argon gas pressure reducing valve was adjusted to 0.05-0.1 MPa, the flow meter was set to 90-100 mL / min, the crucible was purged for 5 min, the temperature was raised from 5℃ to 60℃, and held for 30-60 min. During this period, the mixture was stirred every 5 min with a quartz rod at 500-600 r / min. After melting, the heating was turned off, and argon gas was continued to be introduced until the alloy cooled to room temperature, thus obtaining the liquid metal raw material of gallium-indium alloy.

[0025] A further improvement to the technical solution of this invention is that: the preparation of the liquid metal microdroplet suspension that matches the pretreated fabric substrate further includes:

[0026] Deionized water was injected into the ultrasonic cup, and a 20-30 mm stir bar was placed inside. The speed was set to 100-200 r / min. Sodium dodecyl sulfate (SDS) of analytical grade was weighed and added to the water. The mixture was stirred until completely dissolved. The resulting SDS solution was tested and found to have a water content of ≤0.5%. The SDS solution was transferred to the ultrasonic cup, and liquid metal raw materials were added at a speed of 50-100 r / min. After ultrasonic dispersion for 30-60 min, a milky white metal droplet suspension was obtained.

[0027] Take 1 mL of suspension with a pipette, dilute it 10 times with deionized water, drop 2 drops onto a 200-mesh copper grid, and let it air dry at room temperature for 30 min. Observe 50 microdroplets using a TEM accelerating voltage of 200 kV, and measure the long axis / short axis ratio to be ≤1.2. Take 1 mL of the original suspension and inject it into the DLS sample cell. Detect the zeta potential of -40 to -50 mV using a Zetasizer NanoZS. Repeat 3 times and take the average value to ensure that the microdroplet morphology and surface charge meet the requirements of electric field deposition.

[0028] To ensure the stability of the suspension during electric field deposition and to avoid microdroplet sedimentation, 50 mL of the suspension was pipetted and slowly injected along the wall of the graduated cylinder to avoid generating air bubbles. The stopper was then tightened, the cylinder was placed on a temperature-controlled rack, the initial liquid level was marked, and the cylinder was allowed to stand for 72 hours. If the volume of the supernatant exceeded the limit, the suspension was poured into an ultrasonic cup, 0.05% SDS was added, and the cylinder was ultrasonicated for 5 minutes. The test was repeated.

[0029] A further improvement to the technical solution of this invention lies in: the method of directionally depositing metal microdroplet suspension onto a pretreated substrate to form a discrete structure based on electric field force includes:

[0030] To build a stable electrode system and ensure uniform electric field distribution, titanium alloy clamps were selected. The clamps held the two opposite sides of the fabric substrate. The platinum sheet was soaked in 10% nitric acid for 20-30 minutes, rinsed with deionized water until pH=7.0, and dried with nitrogen. The fabric-cathode and platinum sheet-anode were placed in the electrolytic cell in parallel, and the distance was measured and adjusted to 5.0±0.1cm.

[0031] The liquid metal raw material is injected into the electrolytic cell through a funnel, with the liquid level 2 cm above the electrodes. The thermocouple is inserted into the solution and connected to a temperature controller. The temperature is set to 20-25℃ and allowed to stand for 2-5 minutes until there are no bubbles in the solution. The solution temperature is kept stable to avoid convection affecting the distribution of microdroplets.

[0032] Furthermore, the power supply is set to linear boost mode, with an initial voltage of 8V, rising to 10.0±0.1V within 30 seconds. The voltage and current values ​​are displayed on the screen in real time. A 10Ω precision resistor is connected in series, and the voltage waveform is monitored with an oscilloscope to ensure a current density of 0.5-0.8mA / cm². 2 Deposition was carried out for 15 minutes, during which voltage and current values ​​were recorded every 3 minutes to ensure stable electric field parameters and uniform droplet directional migration rate.

[0033] The electrolytic cell stirrer is set to a speed of 50-100 r / min and rotated clockwise. The liquid metal raw material precipitates onto the fabric substrate. The fabric is lifted with a clamp and drained above the electrolytic cell. It is then vertically rinsed with deionized water from 20-30 cm above the fabric. The metal microdroplet suspension is directionally deposited onto the fabric substrate to form a discrete structure, with the water flow in a columnar shape to avoid direct contact with the microdroplets. A nitrogen gun is held 10 cm away from the fabric substrate and blown at a 45° angle until there are no water droplets on the surface. Under a fluorescence microscope, the microdroplet density and the percentage of agglomerates in five fields of view are counted to see if they are less than 5%, thus preliminarily verifying the uniformity of deposition.

[0034] This application further discloses tests for the mechanical properties of the sedimentary layer, including:

[0035] By aligning the probe of a nanoindenter with the center of a single microdroplet and indenting it at a rate of 50 nm / s, the load-displacement curve is recorded. The peeling force is ≥150 μN. The surface roughness Sa is analyzed by scanning a 10 × 10 μm area in tapping mode using AFM.

[0036] A further improvement of the technical solution of the present invention is that: the formation of a Ga2O3 passivation film on the surface of a metal microdroplet suspension based on controllable oxidation includes: after deposition, the fabric is laid flat on a quartz tray with the metal microdroplet suspension deposition surface facing upwards, placed in the middle layer of a drying oven, the temperature is set to 25±0.5℃ and the humidity to 40±2%, the oven door is closed, the timing is started, and the data is recorded every 10 minutes using a temperature and humidity recorder, and the system is automatically adjusted when the temperature and humidity exceed the range.

[0037] A further improvement of the technical solution of the present invention is that the oxide film detection and performance testing include oxide film detection, dynamic repair performance testing, water wash resistance verification and performance testing.

[0038] The present invention also provides a superhydrophobic polyester fabric, which is prepared by the above-described preparation method.

[0039] Compared with the prior art, the beneficial effects of the present invention are: by pretreating with dopamine to form a polydopamine coating on the surface of polyester, the catechol groups in its molecules can form covalent bonds and hydrogen bonds with the hydroxyl groups on the surface of polyester fibers, providing a stable anchor point for subsequent liquid metal microdroplets, solving the problem of peeling off traditional coatings due to physical adsorption, and significantly improving the durability of the hydrophobic structure.

[0040] Liquid metal microdroplets were prepared using gallium-indium alloy. The fluidity and stability of the metal were balanced by controlling the composition. Combined with ultrasonic dispersion of SDS solution, a microdroplet suspension with uniform size could be formed. Furthermore, electric field-induced self-assembly technology was used to drive the microdroplet deposition in a directional manner using electric field force, avoiding the uneven distribution caused by gravity deposition or immersion deposition, and ensuring the continuity and consistency of the hydrophobic structure.

[0041] By forming a Ga2O3 passivation film on the surface of microdroplets through controlled oxidation, the microdroplets are prevented from agglomerating to maintain a discrete hydrophobic structure, while retaining the fluidity of liquid metal. This allows the microdroplets to rearrange and repair the damaged structure of the fabric through their own flow after being subjected to external forces such as friction and bending, thus solving the defects of traditional rigid hydrophobic layers that are easy to become brittle and difficult to repair. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the process for preparing superhydrophobic polyester fabric. Detailed Implementation

[0043] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0044] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0045] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, and elements well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0046] This invention provides a method for preparing a superhydrophobic polyester fabric. The method includes: using polyester fiber as the fabric substrate and pre-treating it to enhance the adhesion of the fabric substrate and construct a specific roughness; using gallium-indium alloy as a liquid metal raw material to prepare a liquid metal microdroplet suspension that matches the pre-treated fabric substrate; directionally depositing the metal microdroplet suspension onto the pre-treated substrate based on an electric field to form a discrete structure; and forming a Ga2O3 passivation film on the surface of the metal microdroplet suspension through controllable oxidation. The method also includes the following sub-steps:

[0047] S101. Using the diameter of polyester fiber as the screening condition for fabric substrate, a buffer solution of Tris-HCl and dopamine is prepared. The fabric substrate and the buffer solution are polymerized and a dopamine layer is formed on the fabric substrate.

[0048] The polyester fiber-based material also includes the following features:

[0049] Polyester fibers have a diameter of 15-20μm and a contact angle of ≤70°.

[0050] No fiber breakage or impurity particles.

[0051] Furthermore, controlling the fiber diameter deviation within 5μm ensures that the subsequent coating thickness fluctuation is ≤3nm; the contact angle is ≤70° to ensure that the polydopamine solution spreads at a rate ≥2mm / s on the fabric surface, avoiding local drying, and eliminating defective fabrics can reduce the coating defect rate.

[0052] Pretreatment enhances the adhesion of the fabric substrate and creates specific roughness, including:

[0053] (a) The fabric substrate is placed in the cleaning tank and completely immersed in deionized water, with the liquid level 2-5 cm above the fabric substrate. After cleaning with ultrasonic cleaning equipment for 10-15 minutes, the water is changed. The operation is repeated 1-3 times.

[0054] (b) Pipette deionized water into a beaker, place a 30-40 mm stir bar in the beaker, set the stirring speed to 100-300 r / min, weigh Tris powder into the beaker, stir until completely dissolved, add 1 mol / L HCl dropwise to adjust the pH to 8.5 ± 0.1, pipette Tris-HCl buffer into the container, add dopamine hydrochloride, stir magnetically at 200-600 r / min until completely dissolved, and obtain a light pink solution.

[0055] (c) Use tweezers to pick up the ultrasonically cleaned fabric substrate, unfold it and hang it with a quartz hook, with the hook 1cm away from the top of the fabric, and gradually place it in a light pink solution, with the liquid level 1-2cm above the fabric.

[0056] (d) Tighten the container lid and start timing. Every 30 minutes, gently tap the fabric with a quartz rod, touching it from the edge to avoid scratching it. Observe the color change of the solution. It will turn light brown after 20 minutes and dark brown after 2 hours, which means the reaction is over.

[0057] (e) Lift the fabric with a hook, let it drain over the container for 10-30 seconds, then lay it flat on a quartz tray and place it in the middle layer of the oven. Set the temperature to 40-60℃ and the wind speed to 1-1.5m / s. Dopamine forms a coating on the fabric substrate. Dopamine polymerizes evenly on the fabric surface to form a continuous and firmly bonded coating.

[0058] To ensure that the coating thickness and roughness meet the requirements and to provide an ideal substrate for microdroplet adhesion, the following are also included:

[0059] (f) After drying, the fabric substrate is cooled to 25°C and tested with an MS-70 moisture meter. The probe is inserted into the fabric at 3 points and the average value is taken to ensure that the moisture content is ≤1%. The probe of the step meter touches the edge of the fabric, i.e. the junction between the coating and the uncoated area, and scans along the horizontal direction to measure 10 lines and take the average thickness. The AFM scans a 5×5μm area in tapping mode to analyze the surface roughness Ra.

[0060] S102. After melting a gallium-indium alloy, drop it into the prepared SDS solution and disperse it ultrasonically to form a metal droplet suspension.

[0061] Using gallium-indium alloy as the liquid metal raw material, the following setup is included:

[0062] (1) Add gallium and indium blocks to the crucible at a mass ratio of 7:3. Adjust the argon gas pressure reducing valve to 0.05-0.1MPa, set the flow meter to 90-100mL / min, purge the crucible for 5min, raise the temperature to 60℃ at 5℃, hold for 30-60min, and stir with a quartz rod at 500-600r / min every 5min during this period. After melting, turn off the heating and continue to pass argon gas until the alloy cools to room temperature to obtain the liquid metal raw material of gallium-indium alloy.

[0063] (2) Inject deionized water into the ultrasonic cup, place a 20-30 mm stir bar, set the speed to 100-200 r / min, weigh sodium dodecyl sulfate (analytical grade), add it to the water, stir until completely dissolved, and test the water content of the resulting SDS solution to be ≤0.5%. Transfer the SDS solution to the ultrasonic cup, add liquid metal raw material at a speed of 50-100 r / min, and ultrasonically disperse for 30-60 min to obtain a milky white metal droplet suspension.

[0064] S103. The fabric substrate is stretched and clamped by a clamp, and the fabric and platinum sheet are placed in the electrolytic cell and injected with the obtained metal microdroplet suspension to obtain the precipitated fabric substrate.

[0065] (1) Take 1 mL of suspension with a pipette, dilute it 10 times with deionized water, drop 2 drops onto a 200-mesh copper grid, let it air dry at room temperature for 30 min, observe 50 microdroplets with TEM acceleration voltage of 200 kV, measure the long axis / short axis ratio ≤1.2, take 1 mL of the original suspension and inject it into the DLS sample cell, detect the Zeta potential of -40 to -50 mV with Zetasizer NanoZS, repeat 3 times and take the average value to ensure that the microdroplet morphology and surface charge meet the requirements of electric field deposition;

[0066] (2) In order to ensure the stability of the suspension during electric field deposition and avoid microdroplet sedimentation, 50 mL of suspension was taken with a pipette and slowly injected along the wall of the graduated cylinder to avoid generating air bubbles. The stopper was tightened, the suspension was placed on a constant temperature rack, the initial liquid level was marked, and the suspension was allowed to stand for 72 hours. If the volume of the supernatant exceeded the standard, the suspension was poured into an ultrasonic cup, 0.05% SDS was added, and the suspension was ultrasonicated for 5 minutes. The test was repeated.

[0067] (3) In order to build a stable electrode system and ensure uniform electric field distribution, titanium alloy clamps are selected. The clamps hold the two opposite sides of the fabric substrate. The platinum sheet is soaked in 10% nitric acid for 20-30 minutes, rinsed with deionized water until pH=7.0, and dried with nitrogen. The fabric-cathode and platinum sheet-anode are placed in the electrolytic cell in parallel, and the distance is measured and adjusted to 5.0±0.1cm.

[0068] (4) The liquid metal raw material is injected into the electrolytic cell through the funnel. The liquid level is 2 cm above the electrode. The thermocouple is inserted into the solution and connected to the temperature controller. Set the temperature to 20-25℃ and let it stand for 2-5 minutes until there are no bubbles in the solution. Maintain the solution temperature to avoid convection affecting the distribution of microdroplets.

[0069] Furthermore, the power supply is set to linear boost mode, with an initial voltage of 8V, rising to 10.0±0.1V within 30 seconds. The voltage and current values ​​are displayed on the screen in real time. A 10Ω precision resistor is connected in series, and the voltage waveform is monitored with an oscilloscope to ensure a current density of 0.5-0.8mA / cm². 2 Deposition was carried out for 15 minutes, during which voltage and current values ​​were recorded every 3 minutes to ensure stable electric field parameters and uniform droplet directional migration rate.

[0070] (5) Set the stirring speed of the electrolytic cell to 50-100 r / min and rotate clockwise. The liquid metal raw material precipitates on the fabric substrate. Use a clamp to lift the fabric and drain it above the electrolytic cell. Rinse it vertically with deionized water from 20-30 cm above the fabric. The metal microdroplet suspension is directionally deposited on the fabric substrate to form a discrete structure. The water flow is columnar. Avoid directing the microdroplets. Keep the nitrogen gun 10 cm away from the fabric substrate and blow it at a 45° angle until there are no water droplets on the surface. Under the fluorescence microscope, observe with 488 nm excitation light and count whether the microdroplet density and the number of aggregates in 5 fields of view are less than 5% to preliminarily verify the deposition uniformity.

[0071] This application further discloses tests for the mechanical properties of the sedimentary layer, including:

[0072] (6) The nanoindenter probe is aligned with the center of a single droplet and pressed in at a rate of 50 nm / s. The load-displacement curve is recorded. The peeling force is ≥150 μN. The AFM scans a 10×10 μm area in tapping mode to analyze the surface roughness Sa.

[0073] S104. The precipitated fabric substrate is subjected to oxidation to form a Ga2O3 passivation film, which is then subjected to oxide film detection and performance testing.

[0074] The method involves controlling the oxidation to form a Ga2O3 passivation film on the surface of a metal droplet suspension, including: laying the deposited material flat on a quartz tray with the metal droplet suspension deposited surface facing upwards, placing it in the middle layer of a drying oven, setting the temperature to 25±0.5℃ and the humidity to 40±2%, closing the oven door, starting a timer, recording data every 10 minutes using a temperature and humidity recorder, and automatically adjusting if the temperature and humidity exceed the range.

[0075] Oxide film detection and performance testing, including oxide film detection, dynamic repair performance testing, water wash resistance verification and performance testing.

[0076] The oxide film detection process includes: cutting the fabric into 1×1cm samples, fixing them to the XPS sample stage with conductive adhesive, and placing them in the sample chamber; irradiating with 1486.6eV monochromatic AlKα rays to analyze the surface elements of the microdroplets, with the characteristic peak intensity of Ga2O3 accounting for ≥30%; scanning with an ellipsometry in the wavelength range of 600-1000nm; and calculating the oxide film thickness by fitting the data to verify the oxide film composition and thickness, thereby ensuring a balance between protection and repair performance.

[0077] The dynamic repair performance test includes: the fabric is fixed on the sample stage, the cotton friction head is loaded with 500g, the stroke is 100mm, the speed is 60 times / min, and the water contact angle is measured every 20 times using a contact angle meter; the fabric is clamped in a bending instrument and bent 180° back and forth. After 50 times, the integrity of the microdroplets is observed by SEM, thereby evaluating the stability and self-repair ability of the hydrophobic layer under mechanical action.

[0078] The water resistance verification included: placing the fabric and 50g of standard cotton load fabric into a washing machine, adding 40℃ deionized water and 2g / L standard detergent, selecting the cotton fabric program, washing for 15 minutes, rinsing 3 times, dehydrating for 3 minutes, removing the fabric after every 5 cycles, drying at 60℃ for 30 minutes, and testing the water contact angle and roll-off angle using an inclined table to ensure that the fabric still maintains its superhydrophobic properties after daily washing.

[0079] The performance testing included: adding 5μL of deionized water to a contact angle meter to measure the initial contact angle and roll-off angle; observing the distribution of microdroplets using SEM to check for obvious aggregation; soaking the fabric in deionized water for 24 hours after cutting it into pieces; and detecting the heavy metal content of the leachate using ICP-MS. This comprehensive testing verified the product performance and ensured that it met the requirements for hydrophobicity, structural stability, and safety.

[0080] Example 1: This example verifies the advantages of the technical solution of this application in terms of superhydrophobic properties, durability, and stability. A control experiment is designed with controlled variables to compare the impact of key process parameters or material replacements on the final performance. Specifically, the following settings are included:

[0081] The experimental group prepared the polyester fabric according to the steps disclosed above.

[0082] Control group: The dopamine pretreatment step in S101 was removed, and the original polyester fabric was directly subjected to subsequent microdroplet deposition and oxidation, while other steps were the same.

[0083] In the control group, the polyester was only ultrasonically cleaned, then directly subjected to gallium indium alloy microdroplet electric field deposition, and then under the same oxidation conditions.

[0084] The polyester fibers obtained from the control and experimental groups passed the following tests: initial water contact angle (≥150° for superhydrophobicity), roll-off angle (≤10° for excellent); adhesion test (peel force measured by nanoindentation instrument, ≥150μN for qualified); and wash resistance test (contact angle retention rate after 30 washes). The results are shown in the table below.

[0085] Table 1

[0086] index experimental group control group Initial contact angle (°) 155-160 120-130 Roll angle (°) 5-8 30-40 Peel force (μN) 180-200 50-80 Contact angle (°) after 30 water washes 150-155 90-100

[0087] The results show that the dopamine layer, through covalent bonding between the catechol group and polyester and the roughness construction, significantly improves the adhesion of microdroplets and the stability of the hydrophobic structure. The control group, due to the lack of an anchoring substrate, caused the microdroplets to fall off easily, resulting in a sharp drop in hydrophobic performance.

[0088] Example 2: In this example, gallium-indium alloy was used to prepare microdroplets as the experimental group according to the document scheme. Pure gallium was used to replace the gallium-indium alloy, and all other steps were completely the same as the control group. The experimental group was operated by melting the gallium-indium alloy under argon protection, ultrasonically dispersing it with SDS solution to form 2-3 μm microdroplets, depositing it under an electric field at a Zeta potential of -40 to -50 mV. The control group was operated by using pure gallium under the same melting and dispersion process, and the same deposition and oxidation conditions.

[0089] Finally, the stability of the obtained microdroplet suspensions was tested (stratification rate after standing for 72 hours, ≤10% is excellent); microdroplet sphericity (TEM observation, ≥0.85 is excellent); and long-term hydrophobicity (contact angle decay rate after 6 months of storage).

[0090] The results are shown in the table below:

[0091] Table 2

[0092] index experimental group control group Suspension stratification rate (%) 5-8 30-40 microdroplet sphericity 0.85-0.9 0.6-0.7 Contact angle (°) after 6 months 150-152 110-120

[0093] In summary, gallium-indium alloys lower the melting point and improve fluidity through composition control. The microdroplet dispersion stability and morphology retention are superior to those of pure gallium, avoiding the microdroplet aggregation and hydrophobic structure damage caused by the easy solidification of pure gallium at low temperatures.

[0094] Example 3: To verify the advantages of electric field-induced self-assembly over simple immersion deposition in terms of droplet distribution uniformity, the experimental group in this example used electric field deposition according to the above scheme, while the control group used immersion deposition, that is, the polyester fabric was directly immersed in the droplet suspension for 2 hours without the effect of electric field, and the other steps were the same.

[0095] The experimental group's operation involved fixing the fabric and platinum sheet with a titanium alloy clamp and driving the directional deposition of microdroplets with a 10V electric field. The control group's operation involved directly immersing the fabric in the microdroplet suspension, allowing it to deposit naturally for 2 hours under the same oxidation conditions.

[0096] Finally, the deposition density uniformity of the obtained microdroplet suspensions was tested (statistical analysis using fluorescence microscopy, coefficient of variation ≤5% was considered excellent); surface roughness Sa (AFM detection, 2.5-3.0 μm was considered excellent); and self-cleaning performance (simulated oil roll-off rate, ≥90% was considered excellent). The results are shown in the table below:

[0097] Table 3

[0098] index experimental group control group Coefficient of variation of sedimentary density (%) 3-5 20-30 Surface roughness Sa (μm) 2.8-3.0 1.0-1.5 Oil spillage rate (%) 95-98 50-60

[0099] The electric field force drives the microdroplets to migrate in a directional manner, ensuring that they are uniformly anchored on the rough structure of the dopamine coating to form a regular discrete hydrophobic layer. The control group, due to uneven gravity deposition, has discontinuous hydrophobic regions and reduced self-cleaning performance.

[0100] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0101] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a superhydrophobic polyester fabric, characterized in that, The method includes: using polyester fiber as the fabric substrate and pre-treating it to enhance adhesion and create a specific roughness; using gallium-indium alloy as the liquid metal raw material to prepare a liquid metal microdroplet suspension that matches the pre-treated fabric substrate; directionally depositing the metal microdroplet suspension onto the pre-treated substrate based on an electric field to form a discrete structure; and forming a Ga2O3 passivation film on the surface of the metal microdroplet suspension through controllable oxidation. The method also includes the following sub-steps: S101. Using the diameter of polyester fiber as the screening condition for fabric substrate, a buffer solution of Tris-HCl and dopamine is prepared. The fabric substrate and the buffer solution are polymerized and a dopamine layer is formed on the fabric substrate. S102. After melting a gallium-indium alloy, drop it into the prepared SDS solution and disperse it ultrasonically to form a metal droplet suspension. S103. The fabric substrate is stretched and clamped by a clamp, and the fabric and platinum sheet are placed in the electrolytic cell and injected with the obtained metal microdroplet suspension to obtain the precipitated fabric substrate. S104. The precipitated fabric substrate is subjected to oxidation to form a Ga2O3 passivation film, which is then subjected to oxide film detection and performance testing.

2. The method for preparing a superhydrophobic polyester fabric according to claim 1, characterized in that, The polyester fiber-based material also includes the following features: Polyester fibers have a diameter of 15-20μm and a contact angle of ≤70°. No fiber breakage or impurity particles.

3. The method for preparing a superhydrophobic polyester fabric according to claim 1, characterized in that, The pretreatment process to enhance the adhesion of the fabric substrate and create a specific roughness includes: placing the fabric substrate in a cleaning tank and completely immersing it in deionized water, with the liquid level 2-5 cm above the fabric substrate; cleaning it with an ultrasonic cleaning device for 10-15 minutes; changing the water; and repeating the operation 1-3 times. Pipette deionized water into a beaker, place a 30-40 mm stir bar inside, and set the stirring speed to 100-300 r / min. Weigh Tris powder and pour it into the beaker, stirring until completely dissolved. Add 1 mol / L HCl dropwise to adjust the pH to 8.5 ± 0.

1. Pipette Tris-HCl buffer into a container, add dopamine hydrochloride, and magnetically stir at 200-600 r / min until completely dissolved, yielding a light pink solution.

4. The method for preparing a superhydrophobic polyester fabric according to claim 3, characterized in that, Also includes: Use tweezers to pick up the ultrasonically cleaned fabric substrate, unfold it and suspend it with a quartz hook, then gradually place it in a light pink solution, with the liquid level 1-2 cm above the fabric. Lift the fabric with a hook, let it drain over the container for 10-30 seconds, then lay it flat on a quartz tray and place it in the middle layer of an oven. Set the temperature to 40-60℃ and the airflow to 1-1.5m / s. Dopamine will form a coating on the fabric substrate.

5. The method for preparing a superhydrophobic polyester fabric according to claim 1, characterized in that, The method of using gallium-indium alloy as liquid metal raw material includes the following setup: Gallium and indium blocks were added to the crucible at a mass ratio of 7:

3. The argon gas pressure reducing valve was adjusted to 0.05-0.1 MPa, and the flow meter was set to 90-100 mL / min. The crucible was purged, and the temperature was raised from 5°C to 60°C and held for 30-60 min. During this period, the mixture was stirred every 5 min with a quartz rod at 500-600 r / min. After melting, the heating was turned off, and argon gas was continued to be introduced until the alloy cooled to room temperature, thus obtaining the liquid metal raw material of gallium-indium alloy.

6. The method for preparing a superhydrophobic polyester fabric according to claim 5, characterized in that, The preparation of the liquid metal microdroplet suspension that matches the pretreated fabric substrate further includes: Deionized water was injected into the ultrasonic cup, and a 20-30 mm stir bar was placed inside. The speed was set to 100-200 r / min. Sodium dodecyl sulfate (SDS) of analytical grade was weighed and added to the water. The mixture was stirred until completely dissolved. The resulting SDS solution had a water content of ≤0.5%. The SDS solution was transferred to the ultrasonic cup, and liquid metal raw materials were added at a speed of 50-100 r / min. After ultrasonic dispersion, a milky white metal droplet suspension was obtained.

7. The method for preparing a superhydrophobic polyester fabric according to claim 1, characterized in that, The method of directionally depositing metal microdroplet suspensions onto a pretreated substrate to form discrete structures based on electric field force includes: Titanium alloy clamps are selected for the fixtures. The clamps hold the two opposite edges of the fabric substrate. The platinum sheet is soaked in 10% nitric acid for 20-30 minutes, rinsed with deionized water until pH=7.0, and dried with nitrogen. The fabric and platinum sheet are placed parallel to each other in the electrolytic cell, and the distance is measured. The liquid metal raw material is poured into the electrolytic cell through a funnel, with the liquid level 2 cm above the electrodes. The thermocouple is inserted into the solution and connected to a temperature controller. The temperature is set to 20-25℃ and allowed to stand for 2-5 minutes until no more bubbles appear in the solution. The electrolytic cell stirrer is set to a speed of 50-100 r / min and rotates clockwise. The liquid metal raw material precipitates onto the fabric substrate. The fabric is lifted with a clamp and drained above the electrolytic cell. It is then vertically rinsed with deionized water from 20-30 cm above the fabric. The metal micro-droplet suspension is directionally deposited onto the fabric substrate to form a discrete structure.

8. The method for preparing a superhydrophobic polyester fabric according to claim 1, characterized in that, The process of forming a Ga2O3 passivation film on the surface of a metal droplet suspension by controlled oxidation includes: after deposition, the fabric is laid flat on a quartz tray with the metal droplet suspension deposition surface facing upwards, placed in the middle layer of a drying oven, the temperature is set to 25±0.5℃ and the humidity to 40±2%, the oven door is closed, and timing is started. Data is recorded every 10 minutes using a temperature and humidity recorder, and adjustments are made if the temperature and humidity exceed the range.

9. The method for preparing a superhydrophobic polyester fabric according to claim 1, characterized in that, The oxide film detection and performance testing include oxide film detection, dynamic repair performance testing, water wash resistance verification and performance testing.

10. A superhydrophobic polyester fabric, characterized in that, It is prepared by the method for preparing superhydrophobic polyester fabric according to any one of claims 1-9.

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