Self-driven flexible blades with antibacterial properties and their preparation method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SICHUAN AEROSPACE POLYTECHNIC
- Filing Date
- 2023-04-12
- Publication Date
- 2026-06-30
AI Technical Summary
Existing thermally responsive hydrogel flexible materials have long response times, making it difficult to meet the rapid deformation requirements of underwater equipment blades, and they also lack antibacterial properties, making them difficult to apply in underwater environments.
Electrospinning technology was used to prepare Ti3C2Tx MXene, TiO2 and copper sulfide nanoparticles mixed in acrylamide and acrylic acid solution. Chitosan and dopamine were added for cross-linking to form a photothermal self-driven flexible blade skin material with antibacterial properties, which was then combined with a PVC substrate material.
It achieves rapid and reversible deformation within a narrow temperature range, exhibits excellent antibacterial properties, is suitable for underwater equipment blades, especially artificial robotic fish, and has a simple preparation method that is easy to industrialize.
Smart Images
Figure SMS_1 
Figure SMS_2 
Figure SMS_3
Abstract
Description
Technical Field
[0001] This invention belongs to the field of advanced materials and relates to self-driven flexible materials, specifically to a self-driven flexible blade with antibacterial properties and its preparation method. Background Technology
[0002] Since the beginning of the 21st century, with the development of technology, smart healthcare, wearable devices, industrial manufacturing, and robotics have placed increasingly higher demands on mechanical energy conversion devices, such as miniaturization,
[0003] Lightweighting, flexibility, and intelligence are all features that traditional internal combustion engines and electric motors have encountered development bottlenecks due to their inherent mechanistic limitations.
[0004] To address these needs, self-powered flexible materials have become a key research focus, aiming to achieve energy conservation and device flexibility. In existing self-powered flexible material fabrication, the driving source generally originates from changes in the natural environment. Generally, using light, electric fields, and magnetic fields as driving sources allows for precise and rapid adjustment of material strength, phase transitions, and operating frequencies. However, flexible materials driven by chemical atmospheres, humidity, temperature, and pH typically require liquid or enclosed environments, exhibiting higher requirements for environmental parameters and longer response times.
[0005] Blades are commonly used components in mechanical equipment, typically installed in aircraft or underwater devices. They need to oscillate or rotate to cause changes in airflow or water flow, thereby enabling the related mechanical equipment to move. Currently, research on self-propelled blades is limited. This is because aircraft require large and high-frequency driving forces, and existing materials cannot meet the needs of aircraft blades. For blades in underwater devices, the response time of existing self-propelled materials is still relatively long, making it difficult to achieve rapid deformation that can produce corresponding changes in water flow. In addition, the rigidity of the blade substrate material is usually high, further increasing the difficulty of fabricating corresponding flexible blades.
[0006] When underwater equipment is depleted of power, it typically employs a low-power mode to maintain basic mobility, slowly swimming towards its destination. While existing flexible materials cannot provide sufficient power for large underwater devices, research can be conducted on flexible blades that enable slow movement in smaller devices such as robotic fish. This would provide a self-driving mechanism, allowing these devices to operate in an ultra-low-power mode with even lower energy consumption.
[0007] To address the above situation, the inventors envisioned using light emitted from a light-emitting device mounted on an artificial robotic fish as a driving source. This would allow a corresponding flexible material, acting as the flexible blades of the robotic fish or similar equipment, to undergo self-driven deformation under light irradiation, thereby driving the movement of the equipment. Currently, theoretically usable materials are photothermal deformable materials, meaning materials that automatically deform due to temperature changes under light conditions. Therefore, the following section will introduce thermally responsive materials.
[0008] Thermal energy, as one of the most commonly used forms of energy in production and daily life, has been extensively studied and applied in the field of self-driven deformation materials. Currently, research on such materials focuses primarily on low-melting-point alloys, shape memory polymers, hydrogels, and carbon nanomaterials. For low-melting-point alloys and shape memory polymers, considerable research has been conducted using existing technologies. For example, Ford... [1] The liquid crystal elastomer / liquid alloy composite film used by researchers can change temperature through Joule heating, thereby producing expansion and contraction deformation. This composite film also possesses sensing properties. For example, Wang... [2] Researchers have prepared size-controllable light-driven shape memory polymer films, which generate stable polymer networks through crosslinking and can achieve reversible phase transitions at room temperature using linear or polarized light.
[0009] Hydrogels are a widely used class of materials, possessing advantages such as abundant raw material sources, low preparation costs, and simple preparation methods. They are often used as important research subjects for advanced materials, with the aim of rapid industrialization. Thermally responsive hydrogels can be divided into two categories: those with a lower critical solution temperature (LCST) and those with a higher critical solution temperature (UCST). For UCST hydrogels, the hydrogel absorbs water and expands as the temperature rises, and dehydrates and shrinks as the temperature falls; LCST hydrogels exhibit the opposite behavior. Utilizing this property, researchers have studied some thermally deformable flexible materials, such as Zheng... [3] Researchers used LCST and UCST hydrogels to prepare a bilayer thin film structure. When this material was made into a biomimetic gripper, it was able to grasp objects in various environments such as water, liquid paraffin, and air.
[0010] However, the response time of flexible materials prepared by existing thermally responsive hydrogels is usually relatively long, such as Zheng [3]The materials prepared by others require 10 minutes to complete the deformation for grasping objects; while the response time of the films prepared by the current UCST (or LCST) usually requires more than 20 seconds. If high-speed reversible deformation is to be achieved, the thickness of the prepared film needs to be controlled at the micrometer level. For example, Jiang et al.[4] used PNIPAM and polyurethane to prepare a hydrogel film self-driven material. The PNIPAM layer thickness is about 100 μm. When placed alternately in water at 4 ℃ and 40 ℃, it can produce reversible deformation with a response time of less than 1 second. Thin films are difficult to generate enough deformation force to drive the deformation of the blade substrate material. Therefore, they do not have the prospect of being used to prepare flexible motion that can drive underwater equipment. In addition, the large temperature range for generating reversible deformation is also a defect of existing materials of this type.
[0011] Meanwhile, due to the abundance of bacteria in aquatic environments, and the fact that hydrophilic and porous hydrogel materials are generally suitable for bacterial colonization, the antibacterial properties of flexible blades must be considered when designing them for use in underwater equipment. Currently, numerous methods exist for preparing antibacterial thin layers, such as those developed by Yan Xiaojing. [5] The research progress of electrospun functional nanofibers is described in their paper "Research Progress of Electrospun Functional Nanofibers". However, how to overcome the shortcomings of existing thermally responsive materials while also ensuring that the resulting flexible materials have good antibacterial properties is a challenge in this field.
[0012] In summary, to develop the theoretically feasible material currently envisioned for the fabrication of flexible blades for underwater equipment, it is necessary to research a flexible material that can be driven by the photothermal effect, has a simple fabrication method, and a fast response time. This flexible material should be able to drive the deformation of a blade substrate material with a certain degree of rigidity. More importantly, this flexible blade should also possess good antibacterial properties.
[0013] References cited in this section:
[0014] [1]Ford MJ, Ambulo CP, Kent TA, et al., A multifunctional shape-morphing elastomer with liquid metal inclusions, Proc. Natl. Acad.Sci., 2019, 116(43),21438-21444.
[0015] [2]Wang W., Shen D., Li X., et al., Light-driven shape-memory porous films with precisely controlled dimensions, Angew. Chem. Int. Ed., 2018, 57(8), 2139-2143.
[0016] [3]Zheng J., Xiao P., Le X., et al., Mimosa inspired bilayer hydrogelactuator functioning in multi-environments, J. Mater. Chem. C, 2018, 6(6),1320-1327.
[0017] [4]Jiang S., Liu F., Lerch A., et al., Unusual and superfasttemperature-triggered actuators, Adv. Mater., 2015, 27(33), 4865-4870.
[0018] [5][1] Yan Xiaojing, Liu Tong, Chen Chao. Research progress on electrospun functional nanofibers [J]. Textile Report, 2022, 41(10):31-32+57. Summary of the Invention
[0019] To address the shortcomings of existing technologies, one objective of this invention is to provide a flexible material with a simple preparation method and fast response time, driven by the photothermal effect, as a blade skin material for fabricating flexible blades. This flexible blade can achieve rapid, reversible, self-driven deformation within a narrow temperature range. Furthermore, to facilitate industrialization, the skin material is easy to cut. More importantly, this flexible blade also exhibits good antibacterial properties.
[0020] To achieve the above objectives, the present invention provides the following technical solution:
[0021] A method for preparing a self-driven flexible blade with antibacterial properties, the method comprising the following steps:
[0022] (1) Preparation of blade skin material:
[0023] 1) Take acrylamide and acrylic acid at a molar ratio of 5:1, add potassium persulfate at 1% of the total weight of acrylamide and acrylic acid, add crosslinking agent, N,N,N',N'-tetramethylethylenediamine, sodium polyacrylate and chitosan, mix evenly in water to obtain solution A;
[0024] 2) Add the mixture of Ti3C2Tx MXene and TiO2 to solution A at a weight ratio of 1:1~2, then add copper sulfide nanoparticles, stir evenly, and obtain solution B;
[0025] 3) Electrospinning was performed using solution B as the electrospinning solution to obtain a fiber membrane, which was then treated at 50-60°C for 1-3 hours. The fiber membrane was then placed in a dopamine aqueous solution and crosslinked using EDC and NHS. After crosslinking, it was immersed in Fe... 3+ Ionic solutions and Cu 2+ After immersing in an ionic solution for 12–36 hours, the residual ions are washed away with water to obtain the leaf skin material.
[0026] (2) Place the skin material obtained in step (1) on the blade substrate material and fix it to obtain a sensitive photothermal self-driven flexible blade.
[0027] The volume ratio of N,N,N',N'-tetramethylethylenediamine to water is 1:250; the weight of sodium polyacrylate is 25% of the weight of acrylamide, and the weight of chitosan is 25% of the weight of acrylamide; the weight ratio of the mixture of Ti3C2Tx MXene and TiO2 is 2~5:1; the weight of copper sulfide nanoparticles is 10~20% of the weight of acrylamide; the concentration of dopamine aqueous solution is 10~50 mg / mL; Fe 3+ The concentration of the ionic solution is 0.02 mmol–0.1 mmol; Cu 2+ The concentration of the ionic solution is 0.02 mmol to 0.1 mmol.
[0028] The blade base material includes a thin PVC layer, and the thickness ratio of the base material to the skin material is not higher than 5:12.
[0029] During their research, the inventors of this invention obtained a sensitive photothermal self-driven flexible blade, and have filed a separate patent application entitled "A Sensitive Photothermal Self-Driven Flexible Blade and Its Preparation Method". The inventors will not elaborate on the exploratory experiments involved in this invention.
[0030] Based on the aforementioned patent, this invention explores ways to enhance antibacterial properties. In the initial stages of this exploration, building upon the aforementioned patent, a flexible blade was obtained by adding a small amount of nano-silver to the electrospinning solution. However, it was found that the thermal response bending deformation performance decreased significantly. This may be because the addition of nano-silver affected the photothermal properties of the skin material.
[0031] TiO2 is a common antibacterial agent and heat-sensitive substance. For example, Huang Yubo et al. [2] used it to prepare a biodegradable PHBV / PBAT / TiO2 antibacterial nanofiber membrane, which had an antibacterial rate of over 98.0% against Escherichia coli and Staphylococcus aureus. Based on this, the inventors considered adding it together with Ti3C2Tx MXene. However, although the resulting flexible material still has a certain thermal response bending deformation, the response time is greatly extended, and the antibacterial performance is not well improved.
[0032] Through continuous experimentation, the inventors discovered that, based on the aforementioned method of adding TiO2, replacing part of the sodium polyacrylate with chitosan resulted in a flexible blade skin material with excellent antibacterial properties. The inhibition rates against *Escherichia coli* and *Staphylococcus aureus* reached 92% and 94%, respectively, with almost no impact on deformation curvature and thermal response time. This may be because chitosan itself, as an antibacterial substance, interacts with a certain amount of TiO2 and Cu distributed on the surface of the skin material in the present invention. 2+ A synergistic effect was observed in the antibacterial properties. As shown in a comparative example of the present invention, without the addition of TiO2, simply replacing part of the sodium polyacrylate with chitosan did not significantly improve the antibacterial activity.
[0033] As a specific implementation of the present invention, N,N'-methylenebisacrylamide is used as a crosslinking agent, and the molar concentration of N,N'-methylenebisacrylamide is 0.0216% of that of acrylamide.
[0034] As a specific implementable embodiment of the present invention, the Ti3C2T x The preparation method of MXene is as follows: 3g Ti3C2T x Add 67 mL of 6 M hydrochloric acid containing 6 g LiF, then stir at 60°C for 48 h, wash with deionized water and centrifuge several times until the pH of the supernatant reaches above 6; then disperse the centrifuged precipitate in deionized water and sonicate under Ar2 atmosphere for 2 hours to obtain layered detached Ti3C2Tx MXene.
[0035] As a preferred embodiment of the present invention, the weight ratio of the Ti3C2Tx MXene and TiO2 mixture to solution A is 1:2; the weight ratio of the Ti3C2Tx MXene and TiO2 mixture is 4:1.
[0036] As a preferred embodiment of the present invention, the concentration of the dopamine aqueous solution is 30 mg / mL.
[0037] As a preferred embodiment of the present invention, the Fe 3+ The concentration of the ionic solution is 0.05 mmol, and the Cu... 2+ The concentration of the ionic solution is 0.05 mmol.
[0038] As a specific implementation of the present invention, in step 3), the obtained fiber membrane is treated at 55°C for 2 hours.
[0039] As a specific implementation of the present invention, in step (2), when fixing, the obtained skin material is placed in water and then applied to the blade base material, dried at 50~60°C, and then cooled at room temperature.
[0040] Another object of the present invention is to provide an antibacterial self-propelled flexible blade prepared by the above-described preparation method. A further object is to provide the application of the obtained antibacterial self-propelled flexible blade in the manufacture of blades for underwater motion devices, such as blades for artificial robotic fish.
[0041] The beneficial effects of this invention are:
[0042] 1. All raw materials used in this invention are conventional materials in the field and are readily available; the preparation method of the flexible blade of this invention is simple and does not require special processing conditions. It only requires adjusting the raw material ratio, relevant temperature and time. The electrospinning process used is also a mature technology in the field.
[0043] 2. The flexible blade obtained by this invention can use a relatively rigid material as the blade base material, and can achieve rapid, large-scale reversible self-driven deformation within a narrow temperature range; specifically, within the 28~30℃ range, it can complete bending curvature of 0.16cm in 0.7s and 0.9s respectively. -1 Thermoinduced deformation and recovery deformation.
[0044] 3. The flexible blades obtained by this invention have excellent antibacterial properties, with inhibition rates of 92% and 94% against Escherichia coli and Staphylococcus aureus, respectively.
[0045] 4. The flexible blade skin material obtained by the present invention has the property of being cuttable and can be prepared into any shape, making it suitable for the preparation of blades of various shapes.
[0046] References cited in this section:
[0047] [1] Xu Huayu. Flexible self-driven tactile sensor based on MXene blend [D]. Guangxi University, 2022. DOI:10.27034 / d.cnki.ggxiu.2022.002201.
[0048] [2] Huang Yubo, Liu Sihan, Lei Zhenzhen, et al. Preparation of biodegradable PHBV / PBAT / TiO2 antibacterial nanofiber membrane [J]. Knitting Industry, 2023, No.410(03):35-40. Detailed Implementation
[0049] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.
[0050] Explanation of some terms involved:
[0051] MBAA: N,N'-methylenebisacrylamide
[0052] TEMED: N,N,N',N'-Tetramethylethylenediamine
[0053] AAm: Acrylamide
[0054] AAc: Acrylic acid
[0055] Some of the raw materials involved:
[0056] PVA, Chitosan: Wuxi Yatai United Chemical Co., Ltd.
[0057] Sodium polyacrylate: Wuxi Yatai United Chemical Co., Ltd.
[0058] Acrylamide, acrylic acid: Shanghai Aladdin Biochemical Technology Co., Ltd.
[0059] Example 1
[0060] Substrate material preparation:
[0061] Cut commercially available PVC boards evenly into thin layers with a thickness of 0.5mm, smooth them with fine sandpaper, and cut them into strips 5cm long and 1cm wide.
[0062] Skin material preparation:
[0063] Take 1.0662 g AAm (0.015 mol), 0.21618 g AAc (0.003 mol), potassium persulfate (1% by weight of the sum of AAm and AAc), MBAA (0.0216% by molar concentration of AAm), sodium polyacrylate (25% by weight of AAm), chitosan (25% by weight of AAm), TEMED (20 μL), and deionized water (5 mL), and stir vigorously to mix the components to obtain a homogeneous solution. Add a mixture of Ti3C2TxMXene and TiO2 (particle size distribution 100–200 nm) at a weight ratio of 1:2 (Ti3C2TxMXene to TiO2 weight ratio 4:1) to the solution, then add 15% by weight of copper sulfide nanoparticles (particle size distribution 80–200 nm) at AAm, and stir slowly at room temperature for 12 hours to obtain an electrospinning solution. During electrospinning, the feed rate was 1.2 mL / h, the temperature was 32℃, and the receiving distance was 25 cm. The resulting fiber membrane was placed in 55℃ for 2 hours. After obtaining the electrospun fiber membrane, it was placed in a dopamine aqueous solution (dopamine concentration of 30 mg / mL) and crosslinked with EDC and NHS. After crosslinking, it was immersed in Fe... 3+ Ionic solutions and (0.05 mmol) Cu 2+ The material was immersed in an ion solution (0.05 mmol) for 24 hours, and then washed with deionized water to remove residual ions, thus obtaining the skin material.
[0064] Flexible blade preparation:
[0065] The obtained skin fiber was placed in deionized water for 2 minutes, then applied to a 0.5 mm thick PVC substrate, dried at 55°C for 5 hours, and then cooled at room temperature (25-30°C) to obtain a flexible blade containing a PVC substrate.
[0066] The preparation method of Ti3C2Tx MXene is as follows: 3g of Ti3C2Tx is added to 67 mL of hydrochloric acid with a concentration of 6M containing 6g of LiF. The mixture is then stirred at 60°C for 48 h, washed with deionized water and centrifuged several times until the pH of the supernatant reaches above 6. After that, the centrifuged precipitate is dispersed in deionized water and then sonicated under Ar2 atmosphere for 2 hours to obtain layered Ti3C2Tx MXene, which is then pulverized into powder (particle size 200~250μm).
[0067] Example 2
[0068] Besides Fe 3+ The concentration of the ionic solution is 0.02 mmol, Cu 2+ Except for the ion solution concentration being 0.1 mmol, everything else was the same as in Example 1.
[0069] Example 3
[0070] Besides Fe 3+ The concentration of the ionic solution is 0.1 mmol, Cu 2+ Except for the ion solution concentration of 0.02 mmol, the rest is the same as in Example 1.
[0071] Example 4
[0072] Except that the weight of the copper sulfide nanoparticles is 10% of AAM and the concentration of the dopamine aqueous solution is 50 mg / mL, the rest is the same as in Example 1.
[0073] Example 5
[0074] Except that the weight of the copper sulfide nanoparticles is 20% of AAM and the concentration of the dopamine aqueous solution is 10 mg / mL, everything else is the same as in Example 1.
[0075] Example 6
[0076] Except that the weight ratio of the Ti3C2Tx MXene and TiO2 mixture to the solution obtained in the previous step is 1:1, everything else is the same as in Example 1.
[0077] Example 7
[0078] Except for the weight ratio of Ti3C2Tx MXene to TiO2 being 2:1, everything else is the same as in Example 1.
[0079] Example 8
[0080] Except for the weight ratio of Ti3C2Tx MXene to TiO2 being 5:1, everything else is the same as in Example 1.
[0081] Comparative Example 1
[0082] Except for the absence of TiO2 and the fact that the weight ratio of Ti3C2Tx MXene to the solution obtained in the previous step is 1:5, everything else is the same as in Example 1.
[0083] Comparative Example 2
[0084] Except for the absence of TiO2 and the weight ratio of Ti3C2Tx MXene to the solution obtained in the previous step being 1:5, the absence of chitosan and the weight of sodium polyacrylate being 50% of AAM, and the addition of 8% of silver nanoparticles (with a particle size distribution of 80~120nm) by weight of AAM during the preparation of the electrospinning solution, the rest is the same as in Example 1.
[0085] Comparative Example 3
[0086] Except for the absence of chitosan and the fact that the weight of sodium polyacrylate is 50% of AAM, everything else is the same as in Example 1.
[0087] Experimental Example 1
[0088] Self-bending and responsiveness tests were conducted on the products obtained in Examples 1-8 and Comparative Examples 1-3.
[0089] Self-bending and responsiveness test
[0090] The phase transition temperature of the skin materials obtained in Examples 1-8 was investigated, and it was found that the phase transition temperature was around 29°C. The water absorption of the flexible material increased rapidly from 100-110% at 28°C to 1100-1150% at 30°C.
[0091] The flexible blades obtained from each embodiment and each comparative embodiment were placed in a water bath at 28°C, and then transferred to a water bath at 30°C. High-speed cameras were used to take pictures, and their deformation and corresponding time were observed. The results are shown in Table 1.
[0092] Table 1
[0093]
[0094] A deformation-recovery experiment was conducted on Example 1. The flexible blade was first placed in a water bath at 28°C, and then transferred to a water bath at 30°C. It was then transferred from the 30°C water bath to the 28°C water bath. The deformation recovery time was found to be 0.9 s.
[0095] Experimental Example 2
[0096] Antibacterial test: The test was conducted in accordance with GB / T 20944.3—2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", with Escherichia coli and Staphylococcus aureus as test bacteria.
[0097] The skin materials obtained in Examples 1-8 and Comparative Examples 1-3 were subjected to the above antibacterial tests, and the results are shown in Table 2.
[0098] Table 2
[0099]
[0100] Note: The values in Table 2 are rounded to the nearest integer.
[0101] Since the technical solution of this patent is based on a separate patent application filed by the inventor entitled "A Sensitive Photothermal Self-Driven Flexible Blade and Its Preparation Method", the inventor has also recorded the preliminary experiments of the aforementioned patent in this patent to facilitate a better understanding of the technology of this patent by those skilled in the art.
[0102] Preliminary experiment:
[0103] When introducing the embodiments of the present invention, the inventors first describe the preliminary experiments conducted before obtaining the technical solution of the present invention, so that those skilled in the art can better understand the present invention.
[0104] 1. Preparation of skin fibers
[0105] Option 1: Referencing Xin-Jie Luo et al. [1] The Ti3C2Tx MXene material was prepared as follows: 3g of Ti3C2Tx was added to 67 mL of 6M hydrochloric acid containing 6g of LiF. The mixture was then stirred at 60°C for 48 h. After washing with deionized water and centrifuging several times, the pH of the supernatant reached above 6. The centrifuged precipitate was then dispersed in deionized water and sonicated under Ar2 atmosphere for 2 hours to obtain layered Ti3C2Tx MXene, which was then pulverized into powder (particle size 200~250μm).
[0106] Ti3C2Tx MXene powder was mixed into a PVA aqueous solution (PVA concentration 20 w / w%) at a weight ratio of 1:5 and electrospinned to obtain skin fiber 1 (fiber thickness 1.2 mm). During electrospinning, the feed rate was 1.6 mL / h, the temperature was 37 °C, and the receiving distance was 25 cm.
[0107] Option 2: Using a weight ratio of 1:5.6:5.5:1.55:0.06:6, take Ti3C2TxMXene, acrylic acid, acrylamide, sodium hydroxide, potassium persulfate, and PVA from Option 1. Dissolve PVA in water to prepare a PVA aqueous solution. Add acrylic acid to deionized water and stir, then add sodium hydroxide and continue stirring. Finally, add acrylamide and stir again to obtain solution A. Add solution A dropwise to the PVA aqueous solution under high-speed stirring, purge with nitrogen to remove air, then add potassium persulfate, stir at 50°C for 2 hours, and then stir at 59°C for 5 hours to prepare an aqueous solution with a solute weight fraction of 18%. Then, add Ti3C2TxMXene to the obtained aqueous solution at a weight ratio of 1:5, stir evenly, and add glutaraldehyde (to a final concentration of 3%) to obtain a spinning solution. Perform electrospinning to obtain skin fiber 2 (fiber thickness 1.2 mm). During electrospinning, the feed rate is 1.1 mL / h, the temperature is 37°C, and the receiving distance is 25 cm.
[0108] Scheme 3: Acetone and DMF were mixed in a weight ratio of 1:4, and then 75% (by weight) of polyvinylidene fluoride (PVDF) was added to the mixture. The mixture was thoroughly mixed to obtain an electrospun fiber solution. 150% (by weight) of Ti3C2Tx MXene (obtained using the same method as Scheme 1) was added to the electrospun fiber solution, and the mixture was slowly stirred at room temperature for 12 hours. Electrospinning was then performed to obtain skin fiber 3 (fiber thickness 1.2 mm). During electrospinning, the feed rate was 1.5 mL / h, the temperature was 37℃, and the receiving distance was 25 cm.
[0109] Scheme 4: Take 1.0662g of acrylamide, 0.21618g of acrylic acid, potassium persulfate (1% by weight of the sum of AAM and AAc), MBAA (0.0216% by molar concentration of the sum of AAM and AAc), TEMED (20μL), and deionized water (5mL), and stir vigorously to mix the components to obtain a homogeneous solution. Add Ti3C2Tx MXene (obtained by the same method as in Scheme 1) to the solution at a weight ratio of 1:5, and stir slowly at room temperature for 12 hours to obtain an electrospinning solution. During electrospinning, the feed rate is 1.2mL / h, the temperature is 32℃, and the receiving distance is 25cm. The obtained fiber membrane is placed at 55℃ for 2 hours to obtain skin fiber 4 (fiber thickness 1.2mm).
[0110] Option 5: Based on Option 4, without adding Ti3C2Tx MXene, the rest remains the same.
[0111] Option 6: Based on Option 4, when preparing the electrospinning solution, sodium polyacrylate with a weight of 50% AAm is added, and the rest is the same as in Example 4.
[0112] Option 7: Based on Option 6; after obtaining the electrospun fiber membrane, place the electrospun fiber membrane in a dopamine aqueous solution (dopamine concentration of 30 mg / mL), and add EDC and NHS for crosslinking. The final concentrations of EDC and NHS are 0.0192 g / mL and 0.0115 g / mL, respectively.
[0113] 2. Examination of self-bending
[0114] Each of the skin fibers obtained from schemes 1-4 was placed in deionized water for 2 minutes and then attached to a stainless steel sheet. The sheets were dried at 55°C for 5 hours and then cooled at room temperature (25-30°C). The fiber membrane was then peeled off from the stainless steel sheet to obtain the flexible material.
[0115] In a water tank, a flexible material was clamped and submerged in deionized water at a temperature of 28°C. The flexible material was perpendicular to the bottom of the tank. An 808nm (100mW) laser was used to irradiate the flexible material, with the laser horizontal to the bottom of the tank at a distance of 15cm. The bending of the flexible material obtained from each method was observed. High-resolution cameras were used to take pictures within 5 minutes of irradiation, and the bending angles were observed, as shown in Table 3.
[0116] Table 3
[0117]
[0118] Note: Values in the above tables are rounded to two decimal places. The same applies to other tables representing curvature.
[0119] Table 3 shows that when Ti3C2Tx MXene powder is electrospun into PVA fibers, the resulting fibers essentially lose their self-bending properties. This is consistent with Xin-Jie Luo's findings. [1] The self-bending properties achieved by directly fabricating Ti3C2Tx MXene into thin layers were significantly different from those observed in other studies. A possible reason is that LDPE itself is thermally sensitive; while Ti3C2Tx MXene can promote the thermal response and self-crease properties of LDPE, in PVA fibers, due to PVA's low thermal responsiveness and the failure of Ti3C2Tx MXene to promote its thermal response, the resulting fibers exhibited almost no deformation. Similarly, scheme 2 also failed to produce significant self-bending deformation.
[0120] In scheme 3, the inventors replaced materials such as PVA in the electrospinning solution with polyvinylidene fluoride, but still did not find that the resulting product exhibited the corresponding thermally responsive self-bending deformation. It is worth noting that this material has been reported in other studies to possess self-powering capabilities. [2] .
[0121] In Scheme 4, the inventors discovered that the obtained flexible material has a certain self-bending effect. Through experiments, they found that its self-bending curvature reaches 0.04 cm after 125 seconds. -1 This effect was maintained until the end of the experiment. The reason for this may be that the material used in Scheme 4 is heat-sensitive; the resulting fiber membrane exhibits stronger water absorption when the temperature rises, thus causing corresponding deformation. For Scheme 5, the addition of Ti3C2Tx MXene has a significant impact on self-bending deformation, possibly because Ti3C2Tx MXene also has endothermic properties, promoting the self-bending performance of the resulting flexible material. For Scheme 6, blending sodium polyacrylate with the material in Scheme 4 slightly affects the self-bending effect of the resulting flexible material.
[0122] Surprisingly, in Scheme 7, after the inventors modified the fiber membrane obtained in Scheme 6 with dopamine, the resulting flexible material produced a curvature change of 0.23 after 8 seconds and maintained it until the end of the experiment.
[0123] 3. Response assessment
[0124] Inspired by Scheme 7, the inventors investigated the corresponding temperature and time of the flexible material obtained in Scheme 7, and found that the phase transition temperature of the material obtained in Scheme 7 was around 29°C, and the water absorption of the flexible material rapidly increased from 100% at 28°C to 1100% at 30°C. This indicates that the flexible material obtained in Scheme 7 has high temperature-sensitive deformation properties.
[0125] 5. Optimize the experiment
[0126] Through the investigation of the above schemes, the invention obtained a flexible material with high sensitivity and thermal response deformation.
[0127] However, since blades typically require high strength, and the base material usually has high rigidity, ordinary flexible materials are generally difficult to use as blade skin materials. In this part of the experiment, the inventors used PVC (polyvinyl chloride) as the blade base material and examined the self-driven curling ability of the blade when the flexible material obtained in Scheme 7 was used as the skin material. The specific preparation method is as follows: the skin fiber obtained in Scheme 7 was placed in deionized water for 2 minutes, then applied to a PVC thin layer (0.5 mm), dried at 55°C for 5 hours, and then cooled at room temperature (25-30°C) to obtain a flexible blade containing a PVC thin layer. Using the same self-bending test method as described above, it was found that the bending curvature of the obtained flexible blade was only 0.06 cm within 5 minutes of irradiation. -1 .
[0128] Based on this, in order to further improve the self-driven bending performance, the inventors explored the following technical solutions:
[0129] Option 8: Based on Option 7, immerse the cross-linked electrospun fiber membrane in Fe... 3+ The material was immersed in an ion solution (0.05 mmol) for 24 hours, and then washed with deionized water to remove residual ions, yielding skin material 8.
[0130] Option 9: Based on Option 8, the electrospun fiber membrane will also be treated with 0.05 mmol of Cu. 2+ The skin material 9 was obtained by soaking in an ionic solution for 24 hours, while keeping the rest consistent with scheme 8.
[0131] Option 10: Based on Option 8, add Fe 3+ Replace the ionic solution with Mg of the same concentration 2+The ionic solution, with the rest remaining consistent with Scheme 8, yields skin material 10.
[0132] Option 11: Based on Option 10, the electrospun fiber membrane will also use Cu. 2+ After soaking in the ionic solution for 24 hours, the rest of the process remained the same as in Scheme 8, resulting in skin material 11.
[0133] Scheme 12: Based on Scheme 9, when preparing the electrospinning solution, 15% copper sulfide nanoparticles (with a particle size distribution of 80~200nm) with a weight of AAM are added, while the rest remains the same as Scheme 9, to obtain skin material 12.
[0134] As shown in Table 4, when Fe is incorporated 3+ After ionization, the self-driven bending performance of the resulting flexible blades was enhanced, but not significantly; inspired by this, the inventors experimented with other ions, such as Mg. 2+ However, no effect was found on the self-driving bending performance of the resulting flexible blades; but it was found that the simultaneous addition of Fe... 3+ Ions and Cu 2+ After ionization, the self-driven bending performance of the resulting flexible blades was significantly enhanced. Surprisingly, the flexible blades prepared using the skin material obtained in Scheme 12 achieved a bending curvature of 0.17 cm after 12 seconds of irradiation. -1 It reached 0.21 cm at 18 seconds. -1 And keep it until the end of the experiment.
[0135] Table 4
[0136]
[0137] Thus, the inventors completed the research and development of a highly sensitive photothermal response self-driven flexible blade.
[0138] A responsiveness experiment was conducted on the flexible blade fabricated according to scheme 12. The flexible blade was first placed in a 28℃ water bath, then transferred to a 30℃ water bath. High-speed cameras were used to photograph the blade and observe its deformation. The results showed that after being transferred to the 30℃ water bath, the resulting flexible blade exhibited a bending curvature of 0.19 cm within 0.5 seconds. -1 When it was transferred to a 28°C water bath, it completed its original deformation (curvature -0.19cm) within 0.6 seconds. -1 ).
[0139] References cited in this section:
[0140] [1]Luo XJ, Li L, Zhang HB, et al. Multifunctional Ti3C2Tx MXene / Low-Density Polyethylene Soft Robots with Programmable Configuration for Amphibious Motions[J]. ACS applied materials&interfaces, 2021(38):13.
[0141] [2] Xu Huayu. Flexible self-driven tactile sensor based on MXene blend [D]. Guangxi University, 2022.
Claims
1. A method for preparing a self-driven flexible blade with antibacterial properties, characterized in that, The preparation method includes the following steps: (1) Preparation of blade skin material: 1) Take acrylamide and acrylic acid at a molar ratio of 5:1, add potassium persulfate at 1% of the total weight of acrylamide and acrylic acid, add crosslinking agent, N,N,N',N'-tetramethylethylenediamine, sodium polyacrylate and chitosan, mix evenly in water to obtain solution A; 2) Add the mixture of Ti3C2Tx MXene and TiO2 to solution A at a weight ratio of 1:1~2, then add copper sulfide nanoparticles, stir evenly, and obtain solution B; 3) Electrospinning was performed using solution B as the electrospinning solution to obtain a fiber membrane, and the obtained fiber membrane was treated at 50~60℃ for 1~3 hours; then the fiber membrane was placed in a dopamine aqueous solution and crosslinked with EDC and NHS; After cross-linking, it is immersed in Fe 3+ Ionic solutions and Cu 2+ After immersing in an ionic solution for 12–36 hours, the residual ions are washed away with water to obtain the leaf skin material. (2) Place the skin material obtained in step (1) on the blade substrate material and fix it to obtain a sensitive photothermal self-driven flexible blade. The volume ratio of N,N,N',N'-tetramethylethylenediamine to water is 1:250; the weight of sodium polyacrylate is 25% of the weight of acrylamide, and the weight of chitosan is 25% of the weight of acrylamide; the weight ratio of Ti3C2Tx MXene to TiO2 is 2~5:1; the weight of copper sulfide nanoparticles is 10~20% of the weight of acrylamide; the concentration of dopamine aqueous solution is 10~50 mg / mL; Fe 3+ The concentration of the ionic solution is 0.02 mmol–0.1 mmol; Cu 2+ The concentration of the ionic solution is 0.02 mmol to 0.1 mmol. The blade base material includes a thin PVC layer, and the thickness ratio of the base material to the skin material is not higher than 5:
12.
2. The preparation method according to claim 1, characterized in that, N,N'-methylenebisacrylamide is used as a crosslinking agent, and the molar concentration of N,N'-methylenebisacrylamide is 0.0216% of that of acrylamide.
3. The preparation method according to claim 1, characterized in that, The preparation method of the Ti3C2Tx MXene is as follows: 3g Ti3C2T x Add 67 mL of 6 M hydrochloric acid containing 6 g LiF, then stir at 60°C for 48 h, wash with deionized water and centrifuge several times until the pH of the supernatant reaches above 6; then disperse the centrifuged precipitate in deionized water and sonicate under Ar2 atmosphere for 2 hours to obtain layered detached Ti3C2Tx MXene.
4. The preparation method according to claim 1 or 3, characterized in that, The weight ratio of the Ti3C2Tx MXene and TiO2 mixture to solution A is 1:2; the weight ratio of Ti3C2Tx MXene to TiO2 is 4:
1.
5. The preparation method according to claim 1, characterized in that, The concentration of the dopamine aqueous solution is 30 mg / mL.
6. The preparation method according to claim 1, characterized in that, Fe 3+ The concentration of the ionic solution is 0.05 mmol, and the Cu... 2+ The concentration of the ionic solution is 0.05 mmol.
7. The preparation method according to claim 1, characterized in that, In step 3), the obtained fiber membrane is treated at 55°C for 2 hours.
8. The preparation method according to claim 1, characterized in that, In step (2), when fixing, the obtained skin material is placed in water and then applied to the blade base material, dried at 50~60°C, and then cooled at room temperature.
9. A self-propelled flexible blade with antibacterial properties, characterized in that, The antibacterial self-driving flexible blade is prepared by the preparation method according to any one of claims 1 to 8.
10. The application of the antibacterial self-propelled flexible blade as described in claim 9 in the manufacture of blades for underwater motion devices.