Self-healing material for underwater flow field sensing and preparation method and application thereof
By introducing self-healing materials and self-folding microstructures into underwater flow field sensing materials, and combining PBS and conductive filler with a spray-rolling process, the problem of easy material damage in underwater environments was solved, achieving rapid self-healing and high-sensitivity flow field sensing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-23
AI Technical Summary
Existing underwater flow field sensing materials are easily damaged in complex underwater environments. Traditional materials are costly to design and lack self-healing properties, making them unable to work stably for a long time.
By combining self-healing materials with self-folded microstructures, the self-healing properties of PBS and conductive fillers (such as multi-walled carbon nanotubes and graphene nanosheets) are utilized to rapidly restore function in an underwater environment. The interfacial bonding force is enhanced through a spray-rolling process to form a self-healing and self-folded microstructure.
This technology enables underwater flow field sensing materials to rapidly self-repair after damage, improving the lifespan and sensitivity of sensing devices and allowing them to continuously sense flow field disturbances in underwater environments.
Smart Images
Figure CN122255745A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of underwater sensing and smart materials technology, specifically relating to a self-healing material for underwater flow field sensing, its preparation method, and its application. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] Current underwater flow field sensing technologies face several challenges. The underwater environment presents complex conditions such as unique pressure, temperature, and corrosiveness, making traditional sensing surfaces susceptible to damage and rapid performance degradation, thus hindering long-term stable operation. Furthermore, existing underwater sensing surfaces typically require complex material designs or external protective layers to maintain their long-term performance, increasing manufacturing and maintenance costs.
[0004] To address these challenges, researchers have proposed extending the lifespan of sensing surfaces through self-healing materials. Self-healing materials can restore their structure and function after damage, reducing the impact of external factors on their performance. In recent years, materials containing reversible bonds such as borate esters and polysiloxanes have been extensively studied and applied to self-healing systems for sensor surfaces. However, most of these self-healing materials are limited to conventional solid surfaces or air environments, lacking the excellent self-healing performance exhibited in underwater environments.
[0005] Furthermore, self-folded microstructures have become an important research direction for flow field sensing surfaces in recent years due to their excellent flexibility and sensing capabilities. Self-folded microstructures can undergo structural changes in response to external stimuli, thereby providing response signals. However, these materials typically lack good self-healing capabilities, or the healing process is relatively slow, making long-term, stable flow field sensing impossible. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a self-healing material for underwater flow field sensing, its preparation method, and its application. This invention provides a method for preparing and applying a self-wrinkled microstructure underwater flow field sensing surface with accelerated self-healing by water molecules. The coating provided by this invention can quickly self-heal after damage, exhibits high responsiveness to flow field disturbances, and demonstrates high sensitivity.
[0007] This invention provides an innovative material that combines a self-healing mechanism with a self-folding microstructure. This material can quickly recover its function in an underwater environment and maintain its sensing ability after being subjected to changes in water flow, thereby improving the lifespan of underwater flow field sensing devices.
[0008] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a self-healing material for underwater flow field sensing, wherein the surface of the self-healing material is distributed with irregular micro-protrusions, forming a micro-wrinkled structure; The self-healing material includes conductive fillers and PBS prepolymer; The conductive filler includes multi-walled carbon nanotubes (MWCNTs) and / or graphene nanosheets (GNPs).
[0009] Secondly, the present invention provides a method for preparing the above-mentioned self-healing material for underwater flow field sensing, comprising the following steps: The conductive filler dispersion, PBS prepolymer, and curing agent were mixed and heated and stirred to obtain a composite mixture. The composite mixture is coated onto the surface of a substrate and allowed to stand until it reaches a semi-cured state. Then, a conductive filler dispersion is sprayed onto the surface of the composite mixture, and the interface is rolled using a roller to obtain a composite film, which is then cured.
[0010] Thirdly, the present invention provides a coating or self-healing pressure sensor, comprising the aforementioned self-healing material for underwater flow field sensing.
[0011] Fourthly, the present invention provides the application of the above-mentioned self-healing material for underwater flow field sensing or the self-healing material for underwater flow field sensing prepared by the above-mentioned preparation method or the above-mentioned coating or self-healing pressure sensor in self-healing and / or flow field sensing, preferably in self-healing and / or flow field sensing in a water-containing environment.
[0012] Fifthly, the present invention provides a method for underwater flow field sensing and / or self-healing, comprising placing the self-healing material for underwater flow field sensing described above, or the self-healing material for underwater flow field sensing prepared by the above preparation method, or the above coating or self-healing pressure sensor, in an aquatic environment or a humid environment to perform self-healing and / or flow field sensing.
[0013] One or more of the above technical solutions have the following advantages or beneficial effects: This invention provides a self-healing material for underwater flow field sensing, specifically a self-wrinkled microstructure underwater flow field sensing surface that is accelerated to self-heal by water molecules. The self-healing properties of PBS and the inherent conductivity of conductive fillers (carbon nanotubes and graphene) are used to prepare the self-healing, self-wrinkled microstructure underwater flow field sensing surface.
[0014] When the surface is damaged, the continuity of the PBS matrix is disrupted, accompanied by the breakage of local conductive networks. In aquatic or humid environments, water molecules can promote the reversible exchange and rearrangement of the dynamic bonds in the boronic acid esters of PBS, allowing polymer segments at the fracture interface to reconnect and restore the network structure, thereby accelerating the crack closure process. Simultaneously, the conductive channels formed by MWCNTs / GNPs gradually restore conductive continuity and flow field response signals, enabling the surface to reform a stable microtexture morphology, thus achieving continuous sensing of flow field disturbances in underwater environments and long-term service.
[0015] In existing composite methods, conductive fillers are prone to agglomeration due to van der Waals forces, leading to uneven distribution of conductive pathways. Furthermore, the bonding strength between the conductive layer and the substrate interface is insufficient, making it susceptible to localized slippage during service, resulting in damage to the conductive network. Therefore, this invention, based on obtaining and forming a MWCNT / GNP-PBS composite mixture, further employs a "secondary spraying-rolling" interfacial composite process: MWCNT / GNP dispersion is sprayed onto the surface of the semi-cured film, and rolling treatment is used to embed and enrich the conductive filler at the interface, inhibiting agglomeration, improving uniformity, thereby enhancing interfacial bonding, improving underwater stability, and further enhancing the structural response to underwater flow disturbances.
[0016] The method for preparing the self-healing and self-folding microstructure underwater flow field sensing surface of the present invention has a clear process and is easy to operate. The resulting sensing surface has flexibility, self-healing and underwater applicability, and has good engineering application prospects. Attached Figure Description
[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0018] Figure 1 This is a 1000x SEM image of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Embodiment 1 of the present invention. Figure 2 This is a comparison image of the self-healing and self-folding microstructure underwater flow field sensing surface obtained in Embodiment 1 of the present invention before and after self-healing at 25°C; Figure 3 This is a comparison image of the self-healing and self-folding microstructure underwater flow field sensing surface obtained in Comparative Example 1 of the present invention before and after self-healing at 25°C; Figure 4 This is a three-dimensional image of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Embodiment 1 of the present invention; Figure 5 This is a three-dimensional image of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Comparative Example 2 of this invention. Figure 6This is a three-dimensional image of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Comparative Example 3 of the present invention. Figure 7 This is a 1000x SEM image of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Comparative Example 4 of this invention. Figure 8 This is the relative resistance change curve of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Embodiment 1 of the present invention under different water flow velocities; Figure 9 This is the relative resistance variation curve of the underwater flow field sensing surface of the self-healing and self-folding microstructure obtained in Embodiment 1 of the present invention at different water depths; Figure 10 These are the sensor response curves of the self-healing and self-folding microstructure underwater flow field sensing surface obtained in Embodiment 1 of the present invention at different navigation speeds under three different water environments; Figure 11 This is a graph showing the response time of the self-healing and self-folding microstructure underwater flow field sensing surface obtained in Embodiment 1 of the present invention during underwater sensing. Detailed Implementation
[0019] This invention utilizes the self-healing properties of PBS and the inherent conductivity of carbon nanotubes and graphene to prepare a self-healing, self-wrinkled microstructured underwater flow field sensing surface via a spray-rolling method. When the surface is damaged, the continuity of the PBS matrix is disrupted, accompanied by the breakage of local conductive networks. In an aquatic or humid environment, water molecules can promote the reversible exchange and rearrangement of the dynamic bonds in the borate esters of PBS, allowing the polymer segments at the fracture interface to reconnect and restore the network structure, thereby accelerating the crack closure process. Simultaneously, the conductive channels composed of MWCNTs / GNPs gradually restore conductive continuity and flow field response signals, enabling the surface to reform a stable microtexture morphology, thus achieving continuous sensing of flow field disturbances in underwater environments and long-term service. The preparation method of the self-healing, self-wrinkled microstructured underwater flow field sensing surface of this invention is clear and easy to operate, and the resulting sensing surface combines flexibility, self-healing, and underwater applicability, showing good prospects for engineering applications.
[0020] To achieve the above objectives, the technical solution of the present invention is as follows: In one typical embodiment, the present invention provides a self-healing material for underwater flow field sensing, wherein the surface of the self-healing material is distributed with irregular micro-protrusions, forming a micro-wrinkled structure; The self-healing material includes conductive fillers and PBS prepolymer; The conductive filler includes multi-walled carbon nanotubes (MWCNTs) and / or graphene nanosheets (GNPs).
[0021] Furthermore, the mass ratio of conductive filler to PBS prepolymer is 1:130 to 1:30, preferably 1:124 to 1:39.
[0022] Furthermore, the PBS prepolymer is prepared by heating a mixture of boric acid, a solvent, and polydimethylsiloxane (PDMS). The solvent includes isopropanol.
[0023] Furthermore, the size of the microprotrusions is mainly on the order of micrometers, and the protrusions are distributed in a spaced manner.
[0024] In a typical embodiment, the present invention provides a method for preparing the above-mentioned self-healing material for underwater flow field sensing, comprising the following steps: The conductive filler dispersion, PBS prepolymer, and curing agent were mixed and heated and stirred to obtain a composite mixture. The composite mixture is coated onto the surface of a substrate and allowed to stand until it reaches a semi-cured state. Then, a conductive filler dispersion is sprayed onto the surface of the composite mixture, and the interface is rolled using a roller to obtain a composite film, which is then cured.
[0025] In one or more embodiments, the PBS prepolymer is prepared by heating a mixture of boric acid, a solvent, and polydimethylsiloxane (PDMS). Specifically: boric acid is dispersed in a first solvent, then polydimethylsiloxane (PDMS) is added, the mixture is stirred at 50-70°C, then heated to 100-120°C, the mixture is sonicated, and stirring is continued to obtain the PBS prepolymer.
[0026] Furthermore, the first solvent includes isopropanol. The mass percentage concentration of boric acid in the first solvent is 0.1 wt% to 0.6 wt%, preferably 0.18 wt% to 0.54 wt%.
[0027] Furthermore, the mass ratio of boric acid to polydimethylsiloxane is (0.05~0.5):(10~30), preferably (0.05~0.15):(15~25).
[0028] Furthermore, stir at 50-70°C for 20-40 minutes. Then, sonicate the mixture for 50-70 minutes and continue stirring for 0.5-2 hours.
[0029] In one or more embodiments, the conductive filler is dispersed in a second solvent and ultrasonically treated to obtain a conductive filler dispersion. Preferably, the second solvent comprises hexane. The concentration of the conductive filler dispersion is 5-10 mg / mL, preferably 8.57 mg / mL.
[0030] The addition amount of MWCNT is 0.5~1.5 wt%, and the addition amount of GNP is 0.3~1 wt%, with the mass percentages based on the mass of the composite system ("conductive filler + prepolymer"). To prevent MWCNT and GNP from agglomerating, the dispersion system is ultrasonically treated for 50~70 min at a power of 200~600 W.
[0031] Furthermore, the preparation method of the conductive filler dispersion specifically includes: mixing 0.5~1.5 wt% multi-walled carbon nanotubes (MWCNTs) and 0.3~1 wt% graphene nanosheets (GNPs), then dispersing them in 20~50 mL (preferably 30~40 mL) of hexane solvent, and ultrasonically treating the dispersion system to obtain a uniform dispersion of the conductive filler.
[0032] In one or more embodiments, the specific preparation method of the composite mixture is as follows: the conductive filler dispersion is added to the PBS prepolymer, and a curing agent is added at the same time. The mixture is ultrasonically treated and stirred under heating conditions, and after cooling to room temperature, the composite mixture is obtained.
[0033] Furthermore, the heating temperature is 100~120℃, preferably 110℃, the stirring speed is 1000~2000 rpm, preferably 1500 rpm, and the stirring time is 50~70 min, in order to weaken the van der Waals interactions between the conductive fillers and promote their uniform dispersion in the solvent. Heating is stopped when the solution becomes slightly viscous, and the solution is cooled to room temperature.
[0034] Furthermore, the curing agent includes alkoxysilane crosslinking agents. Specifically, the curing agent may be Dow Corning, model DC184 / SYLGARD184, and the curing agent is used in conjunction with the product.
[0035] The mass ratio of prepolymer to curing agent is (5~20):1, specifically 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, etc., as well as specific values between the two, preferably (9~11):1, and most preferably 10:1.
[0036] Furthermore, in the composite mixture, the volume ratio of the conductive filler dispersion to the PBS prepolymer is (0.5~1.5):(0.5~1.5), preferably 1:1.
[0037] In one or more embodiments, the substrate includes glass or the like.
[0038] In one or more embodiments, the static curing conditions are as follows: static curing at room temperature for 15-30 minutes until a semi-cured state is reached before subsequent spraying. The semi-cured state facilitates the adhesion of particles after spraying.
[0039] In one or more embodiments, the roller is a wool roller with a weight of 0.1~0.5kg, preferably 0.25kg.
[0040] In polymer composites, the most common composite routes generally include physical blending (solution blending, melt blending), in-situ polymerization, and surface structure construction methods such as coating, spraying, lamination, calendering, and rolling. This invention employs a composite construction method combining coating, spraying, and rolling. Based on the implementation method and mechanism of this invention, rolling is used as a step in the composite process because rolling promotes further dispersion, wetting, and enhanced contact of particles at the interface, and facilitates the subsequent formation of self-wrinkled microstructures.
[0041] In one or more embodiments, the spraying amount of the conductive filler dispersion is 2-5 mL / (the substrate area to be sprayed is 25 cm²). 2 The amount of coating applied depends on the specific surface condition after coating. If the amount of coating is too small, it may cause uneven self-wrinkling and discontinuous surface coverage. If the amount of coating is too large, it may cause surface particles to accumulate, resulting in an excessively thick surface and disrupting the surface condition.
[0042] Furthermore, the composite film obtained by rolling is cured at a temperature of 80~100℃ for a time of 0.5~2h. Preferably, the curing temperature is 85~95℃ for a time of 50~70 min. The curing temperature affects the surface morphology of the subsequent coating. If room temperature curing is used, the sample surface will not have obvious undulating microstructures.
[0043] Cut the obtained material to your desired size for practical application; for example, cut it into 3×3 cm pieces. 2 Flake-like.
[0044] As a preferred embodiment, the method for preparing a self-healing material for underwater flow field sensing includes the following steps: (1) Boric acid was fully dispersed in isopropanol, and then polydimethylsiloxane (PDMS) was added to it. After magnetic stirring, the mixture was heated, sonicated and stirred to obtain prepolymer PBS. (2) Multi-walled carbon nanotubes (MWCNTs) and graphene nanosheets (GNPs) were mixed and dispersed in hexane solvent, and the dispersion system was ultrasonically treated to obtain a uniform dispersion of conductive filler. (3) The obtained conductive filler dispersion was added to the PBS prepolymer, and a curing agent was added at the same time. The mixture was ultrasonically treated and stirred. After cooling to room temperature, a mixture of MWCNT / GNP-PBS was obtained. (4) The composite mixture obtained in step (3) is coated on the surface of a clean glass substrate. After semi-curing at room temperature, the conductive filler dispersion is sprayed onto the surface of the composite mixture, and the interface is rolled by a wool roller so that the conductive filler enters and is distributed on the surface of the composite mixture under the synergistic effect of pressure, electrostatic force generated by friction and capillary force enhanced along the nanoparticle channel. (5) The composite film treated in step (4) is cured to form a self-wrinkled microtexture structure.
[0045] (6) Cut the cured composite film into 3×3 cm pieces. 2 The sheet-like structure yields a flexible, micro-textured, self-healing pressure sensor.
[0046] In one typical embodiment, the present invention provides a coating or self-healing pressure sensor comprising the aforementioned self-healing material for underwater flow field sensing.
[0047] In one typical embodiment, the present invention provides the application of the above-mentioned self-healing material for underwater flow field sensing or the self-healing material for underwater flow field sensing prepared by the above-mentioned preparation method or the above-mentioned coating or self-healing pressure sensor in self-healing and / or flow field sensing, preferably in self-healing and / or flow field sensing in aquatic environments.
[0048] In self-healing applications, complete repair is achieved in air within 50–65 minutes (preferably 55–65 minutes). In underwater environments at 20–30°C, complete repair is achieved in 30–45 minutes (preferably 35–40 minutes).
[0049] The self-healing performance test in this invention was mainly conducted at room temperature. Based on the mechanism of dynamic bonds of borate esters and water molecules accelerating repair, it has been proven that the system can quickly restore the damaged site and its function underwater.
[0050] In underwater flow field sensing applications, the flow velocity can range from 0.5 to 3 m / s. The signal plateau ranges between different flow velocities show significant differences, and the surface responds quickly when flow velocities change, indicating that the sensing surface of this invention can effectively identify and respond in real time to changes in underwater flow field intensity, demonstrating excellent sensing performance. It exhibits good sensing performance within a water depth range of 0.01 to 0.5 m (preferably 0.05 to 0.15 m).
[0051] The fast response time is 50~150ms, preferably 100~150ms, and most preferably 120ms.
[0052] In one typical embodiment, the present invention provides a method for underwater flow field sensing and / or self-healing, comprising placing the self-healing material for underwater flow field sensing described above, or the self-healing material for underwater flow field sensing prepared by the above preparation method, or the above coating or self-healing pressure sensor, in an aquatic environment or a humid environment to perform self-healing and / or flow field sensing.
[0053] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.
[0054] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.
[0055] Example 1 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: (1) Preparation of prepolymer PBS: 0.1 g boric acid was fully dispersed in 35 mL isopropanol, and then 20 g polydimethylsiloxane (PDMS) was added. The mixture was magnetically stirred at 60 °C (500 rpm) for 30 min, and then heated to 110 °C. The mixture was ultrasonically treated (400 W ultrasonic power, 20 min ultrasonic) and stirred for 1 h (500 rpm) to obtain prepolymer PBS. (2) Preparation of conductive filler dispersion: 1 wt% multi-walled carbon nanotubes (MWCNT) and 0.5 wt% graphene nanosheets (GNP) were mixed and then dispersed in 35 mL hexane solvent. The dispersion system was then ultrasonically treated (ultrasonic power 400 W) for 1 h to obtain a uniform dispersion of conductive filler. (3) Mixing of composite system: 25 mL of the obtained conductive filler dispersion was added to 25 mL of PBS prepolymer (wherein the volume ratio of conductive filler dispersion to PBS prepolymer is 1:1), and 2 g of curing agent was added at the same time (the mass ratio of prepolymer to curing agent is 10:1). The mixture was ultrasonically treated at 110 °C and stirred for 1 h at a stirring speed of 1500 rpm. After cooling to room temperature, a mixture of MWCNT / GNP-PBS was obtained. (4) Film formation and interface phagocytosis treatment: Take 5 mL of the mixture obtained in step (3) and coat it onto the surface of a clean glass substrate (5*5 cm). 2), and let it stand at room temperature for 20 minutes to semi-cure it. Then spray the conductive filler dispersion (3 mL) obtained in step (2) onto the surface of the composite mixture, and use a 0.25 kg wool roller to roll back and forth along the surface 5-10 times, so that the conductive filler enters and distributes on the surface of the composite mixture under the synergistic effect of pressure, electrostatic force generated by friction and capillary force enhanced along the nanoparticle channel. (5) The composite film treated in step (4) is cured at 90°C for 1 hour to form a self-wrinkled microtexture structure.
[0056] (6) Cut the cured composite film into 3×3 cm pieces. 2 The sheet-like structure yields a flexible, micro-textured, self-healing pressure sensor.
[0057] The sensor prepared in Example 1 was placed underwater for sensing performance testing. The results showed that the coating exhibited good self-healing properties and high sensing sensitivity.
[0058] Example 2 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: (1) Preparation of prepolymer PBS: 0.05 g boric acid was fully dispersed in 30 mL isopropanol, and then 15 g polydimethylsiloxane (PDMS) was added. The mixture was magnetically stirred at 60 °C (500 rpm) for 20 min, and then heated to 110 °C. The mixture was ultrasonically treated (400 W ultrasonic power, 20 min ultrasonic) and stirred for another 50 min (500 rpm) to obtain prepolymer PBS. (2) Preparation of conductive filler dispersion: 0.5 wt% multi-walled carbon nanotubes (MWCNT) and 0.3 wt% graphene nanosheets (GNP) were mixed and then dispersed in 30 mL hexane solvent. The dispersion system was then ultrasonically treated (ultrasonic power 400 W) for 50 min to obtain a uniform dispersion of conductive filler. (3) Mixing of the composite system: 25 mL of the obtained conductive filler dispersion was added to 25 mL of PBS prepolymer, along with 1.5 g of curing agent. The mixture was ultrasonically treated at 110 °C and stirred for 50 min at a stirring speed of 1500 rpm. After cooling to room temperature, a mixture of MWCNT / GNP-PBS was obtained. (4) Film formation and interface phagocytosis treatment: Take 5 mL of the mixture obtained in step (3) and coat it onto the surface of a clean glass substrate (5*5 cm). 2After being placed at room temperature for 20 minutes to semi-cure, the conductive filler dispersion (3 mL) obtained in step (2) is sprayed onto the surface of the composite mixture, and a 0.25 kg wool roller is used to roll back and forth along the surface 5-10 times, so that the conductive filler enters and is distributed on the surface of the composite mixture under the synergistic effect of pressure, electrostatic force generated by friction and capillary force enhanced along the nanoparticle channel. (5) The composite film treated in step (4) is cured at 90°C for 1 hour to form a self-wrinkled microtexture structure.
[0059] (6) Cut the cured composite film into 3×3 cm pieces. 2 The sheet-like structure yields a flexible, micro-textured, self-healing pressure sensor.
[0060] Example 3 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: (1) Preparation of prepolymer PBS: 0.15 g boric acid was fully dispersed in 40 mL isopropanol, and then 25 g polydimethylsiloxane (PDMS) was added. The mixture was magnetically stirred at 60 °C (500 rpm) for 30 min, and then heated to 110 °C. The mixture was ultrasonically treated and stirred (500 rpm) for 70 min to obtain prepolymer PBS. (2) Preparation of conductive filler dispersion: 1.5 wt% multi-walled carbon nanotubes (MWCNT) and 1 wt% graphene nanosheets (GNP) were mixed and then dispersed in 40 mL hexane solvent. The dispersion system was then ultrasonically treated (ultrasonic power 400 W) for 70 min to obtain a uniform dispersion of conductive filler. (3) Mixing of composite system: Add 25 mL of the obtained conductive filler dispersion to 25 mL of PBS prepolymer, and add 2.5 g of curing agent at the same time. Sonicate the mixture at 110 °C and stir for 70 min at a stirring speed of 1500 rpm. After cooling to room temperature, a mixture of MWCNT / GNP-PBS is obtained. (4) Film formation and interface phagocytosis treatment: Take 5 mL of the mixture obtained in step (3) and coat it onto the surface of a clean glass substrate (5*5 cm). 2 ), and let it stand at room temperature for 20 minutes to semi-cure it. Then spray the conductive filler dispersion (3 mL) obtained in step (2) onto the surface of the composite mixture, and use a 0.25 kg wool roller to roll back and forth along the surface 5-10 times, so that the conductive filler enters and distributes on the surface of the composite mixture under the synergistic effect of pressure, electrostatic force generated by friction and capillary force enhanced along the nanoparticle channel. (5) The composite film treated in step (4) is cured at 90°C for 1 hour to form a self-wrinkled microtexture structure.
[0061] (6) Cut the cured composite film into 3×3 cm pieces. 2 The sheet-like structure yields a flexible, micro-textured, self-healing pressure sensor.
[0062] Comparative Example 1 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: The difference from Example 1 is that the sample is placed in air. The remaining steps are the same as in Example 1.
[0063] The self-healing and self-folding microstructure underwater flow field sensing surface obtained has the following self-healing properties: Figure 3 As shown, the time required for the sample to achieve the same repair effect was significantly longer than that of Example 1.
[0064] Comparative Example 2 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: The difference from Example 1 is that multi-walled carbon nanotubes (MWCNTs) are not added in step (2). The remaining steps are the same as in Example 1.
[0065] The resulting three-dimensional morphology of the underwater flow field sensing surface with self-healing and self-folding microstructure is as follows: Figure 5 As shown, the overall undulation amplitude of the sample is smaller than that of Example 1, and the distribution of microstructure units is relatively sparse.
[0066] Comparative Example 3 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: The difference from Example 1 is that graphene nanosheets (GNP) are not added in step (2). The remaining steps are the same as in Example 1.
[0067] The resulting three-dimensional morphology of the underwater flow field sensing surface with self-healing and self-folding microstructure is as follows: Figure 6 As shown, the overall undulation amplitude of the sample is smaller than that of Example 1, and the distribution of microstructure units is relatively sparse.
[0068] Comparative Example 4 A method for preparing a self-repairing, water molecule-accelerated underwater flow field sensing surface with a self-folding microstructure includes the following steps: The difference from Example 1 is that the high-temperature induction in step (5) is not performed, and the curing is carried out at room temperature. The remaining steps are the same as those in Example 1.
[0069] The surface morphology of the obtained self-healing and self-folding microstructure underwater flow field sensing surface is as follows: Figure 7 As shown, the sample surface does not exhibit any obvious microstructure with noticeable undulations.
[0070] Performance testing Figure 1 This is a 1000x SEM image of the underwater flow field sensing surface of the self-healing, self-folding microstructure in Embodiment 1 of the present invention. As can be seen from the image, a large number of irregular micro-protrusions are uniformly distributed on the surface, forming a distinct micro-folding structure. The size of these protrusions is mainly on the micrometer scale, and they are evenly spaced. The surface is crack-free, and the structure is stable. This micro-folding structure can increase the effective sensing area, providing a structural response basis for changes caused by underwater flow field disturbances, thereby improving sensing sensitivity and signal stability.
[0071] Self-healing test: The surface of the coating is lightly scratched with a scalpel to create a scratch defect; the damaged sample is then treated at room temperature or a set temperature, and the changes in surface morphology before and after repair are recorded.
[0072] Figure 2 This is a comparison image of the self-healing, self-folding microstructure underwater flow field sensing surface in Embodiment 1 of the present invention before and after self-healing underwater at 25°C. Figure 2 As shown, in an underwater environment at 25℃, the damaged areas on the prepared self-healing and self-folding microstructure underwater flow field sensing surface are gradually repaired over time, and the damaged areas become less and less noticeable. The scratches at the damaged areas gradually become shallower with increasing repair time, and after 40 minutes of repair, the scratches almost completely disappear.
[0073] Figure 3 This is a comparison image of the self-healing process before and after at 25°C in Comparative Example 1 of this invention. (See image for reference.) Figure 3 As shown, when exposed to air, the coating was fully repaired after 60 minutes, significantly slower than in Example 1.
[0074] Perceived performance test: Cut the sensor into 3×3 cm pieces. 2 The device was connected with wires and fixed at the test position inside the water tank. The flow rate was adjusted using a water pump to obtain different flow velocity conditions. The sensor resistance change curve over time was recorded at a depth of 0.15m underwater. During the test (at a temperature of 25℃, primarily focusing on the sensing performance in a 25℃ water environment), the sensor resistance signal was acquired in real time, and the relative signal change (ΔR / R0) was calculated using the no-load state as a baseline.
[0075] Figure 8 , Figure 9 This is the corresponding curve of the sensor made from the self-healing and self-folding microstructure underwater flow field sensing surface in Embodiment 1 of the present invention. Figure 8As shown, the signal plateau ranges between different flow velocities differ significantly, and the surface responds quickly during flow velocity switching, indicating that the sensing surface of this invention can effectively identify and respond in real time to changes in underwater flow field intensity, demonstrating excellent sensing performance. Figure 9 As can be seen, it has good sensing performance in a water depth range of 0.05-0.15m.
[0076] Figure 10 These are sensor response curves of the self-healing, self-folding microstructure underwater flow field sensing surface obtained in Embodiment 1 of the present invention at different navigation speeds under three different water environments. It exhibits good sensing performance under different water environments and speeds.
[0077] Figure 11 The figure shows the response time of the self-healing and self-folding microstructure underwater flow field sensing surface obtained in Embodiment 1 of the present invention during underwater sensing. As can be seen from the figure, its fast response time is 120ms.
[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A self-healing material for underwater flow field sensing, characterized in that, The surface of the self-healing material is covered with irregular micro-protrusions, forming a micro-wrinkled structure; The self-healing material includes conductive fillers and PBS prepolymer; The conductive filler includes multi-walled carbon nanotubes and / or graphene nanosheets.
2. The self-healing material according to claim 1, characterized in that, The microprotrusions are on the order of micrometers in size and are spaced apart.
3. A method for preparing a self-healing material for underwater flow field sensing as described in claim 1 or 2, characterized in that, Includes the following steps: The conductive filler dispersion, PBS prepolymer, and curing agent were mixed and heated and stirred to obtain a composite mixture. The composite mixture is coated onto the surface of a substrate and allowed to stand until it reaches a semi-cured state. Then, a conductive filler dispersion is sprayed onto the surface of the composite mixture, and the interface is rolled using a roller to obtain a composite film, which is then cured.
4. The preparation method according to claim 3, characterized in that, The PBS prepolymer is prepared by heating a mixture of boric acid, solvent and polydimethylsiloxane; preferably, the preparation method is as follows: boric acid is dispersed in a solvent, then polydimethylsiloxane is added to it, the mixture is stirred at 50~70°C, then the temperature is raised to 100~120°C, the mixture is ultrasonically treated and stirred continuously to obtain the PBS prepolymer; Preferably, the mass ratio of boric acid to polydimethylsiloxane is (0.05~0.5):(10~30); Preferably, the conductive filler is dispersed in a solvent and then ultrasonically treated to obtain a conductive filler dispersion. Preferably, the mass ratio of PBS prepolymer to curing agent is (5~20):1; Preferably, the amount of multi-walled carbon nanotubes added is 0.5~1.5 wt%, and the amount of graphene nanosheets added is 0.3~1 wt%.
5. The preparation method according to claim 3, characterized in that, The specific preparation method of the composite mixture is as follows: the conductive filler dispersion is added to the PBS prepolymer, and a curing agent is added at the same time. The mixture is ultrasonically treated and stirred under heating conditions. After cooling to room temperature, the composite mixture is obtained. Preferably, the heating temperature is 100~120℃, the stirring speed is 1000~2000 rpm, and the stirring time is 50~70 min; Preferably, the mixture is allowed to stand at room temperature for 15-30 minutes to cure, reaching a semi-cured state. Preferably, the rollers are made of wool. Preferably, the temperature for curing the composite film obtained by rolling is 80~100℃, and the curing time is 0.5~2h.
6. A coated or self-healing pressure sensor, characterized in that, This includes the self-healing material for underwater flow field sensing as described in claim 1 or 2, or the self-healing material for underwater flow field sensing prepared by the preparation method described in any one of claims 3 to 5.
7. The application of a self-healing material for underwater flow field sensing as described in claim 1 or 2, or a self-healing material for underwater flow field sensing prepared by the preparation method described in any one of claims 3 to 5, or a coating or self-healing pressure sensor as described in claim 6, in self-healing and / or flow field sensing, preferably in self-healing and / or flow field sensing in a water-containing environment.
8. The application according to claim 7, characterized in that, In self-healing applications, it can be fully repaired in air within 50-65 minutes; It can be completely repaired in an underwater environment of 20~30℃ within 30~45 minutes.
9. The application according to claim 7, characterized in that, In underwater flow field sensing applications, when the flow velocity is 0.5~3m / s, the fast response time is 50~150ms.
10. A method for underwater flow field sensing and / or self-healing, comprising placing the self-healing material for underwater flow field sensing as described in claim 1 or 2, or the self-healing material for underwater flow field sensing prepared by the preparation method described in any one of claims 3 to 5, or the coating or self-healing pressure sensor as described in claim 6, in an aqueous environment to perform self-healing and / or flow field sensing.