3D printing method and device for bionic surface with fog collection and droplet manipulation functions

Abstract

The present application relates to the technical field of 3D printing, and particularly relates to a 3D printing method and device with a fog collecting and droplet manipulating function bionic surface, which is used for realizing the preparation and adjustment of the macroscopic and microscopic structures of the intelligent bionic surface with high efficient water collecting function. The printing device contains five hardware parts, including a three-phase material supply system, a digital flow control extrusion system, an ultraviolet polymerization system, a three-dimensional motion platform and an intelligent control system. Through the hardware design of the digital flow control extrusion system containing three-phase materials and the pipeline flow design, combined with the material design of the mutual insolubility and emulsification breaking capacity of the inner phase, the intermediate phase and the outer phase, according to the optimization of the process parameters, the direct formation of the bionic spindle knot shape and the real-time adjustment of the spindle knot size and spacing of the microfiber main shaft are realized, which has great application potential in realizing efficient fog collection and droplet manipulation.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a 3D printing method and apparatus for a biomimetic surface with mist collection and droplet manipulation functions. Background Technology

[0002] Fog harvesting is a technology used to collect water vapor in the atmosphere and convert it into liquid water, with great potential in arid, desert, or water-scarce regions. Spider webs, with their extremely strong fog adsorption and capture capabilities, are a typical example of fog capture and collection in nature. Their excellent fog harvesting ability mainly stems from the superhydrophilic properties of their constituent materials and their unique spindle-joint structure design. The hydrophilic properties of the materials provide efficient fog capture, while the Laplace pressure difference generated by the unique structural design of the spindle joints drives the microdroplets to autonomously converge directionally, thus achieving highly efficient fog capture.

[0003] Traditionally, there are two main methods for manufacturing spider silk-inspired spindle structures: impregnation and electrospinning. These traditional methods have several drawbacks: 1. The manufacturing process is extremely cumbersome and can only achieve a random distribution of microstructures with varying curvature on the fiber, failing to precisely adjust the geometry and spacing of the biomimetic spindle structure; 2. Currently, droplet removal from water collection devices relies solely on gravity, lacking an intelligent active removal mechanism, which significantly impacts the efficiency of mist collection and efficient water collection; 3. The function is limited; traditional methods are confined to a single mist collection function, neglecting the design of efficient water collection through directional liquid transport. Summary of the Invention

[0004] To address the problems of complex manufacturing processes, inability to precisely control microstructures, passive and inefficient droplet shedding, and inability to directionally transport liquids in existing spiderweb-inspired spindle joint structures, this invention provides a 3D printing device with a biomimetic surface that has fog collection and droplet manipulation functions. Furthermore, it provides a 3D printing method for a biomimetic surface with fog collection and droplet manipulation functions.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A 3D printing device with biomimetic surfaces featuring mist collection and droplet manipulation functions includes:

[0007] The three-phase material supply system consists of three material pumping systems, designed to precisely and timed extract and pump multi-material systems into a digital flow extrusion system.

[0008] The digital fluid extrusion system is the core component of the 3D printing device of this invention. It is connected to a three-phase material supply system, which pumps three kinds of materials to different channel inlets of the digital fluid extrusion system. The extrusion of a complex digital fluid system is achieved by combining the hardware physical design of the digital fluid extrusion system with the selection of process parameters.

[0009] The ultraviolet polymerization system irradiates the material extruded by the digital fluid control extrusion system from all directions, thereby achieving instantaneous shape fixation of the spindle segment structure;

[0010] The three-dimensional motion platform, as a basic component of the 3D printing system, controls the movement of the three-dimensional motion platform within its spatial range, thereby depositing the coaxially distributed material system extruded by the digital fluid extrusion system onto the molding platform, realizing the three-dimensional molding with a complex macro- and micro-bionic spider web structure.

[0011] The intelligent control system reverse-engineers a mesh structure model based on the expected function, determines the geometric dimensions and spacing of the spindle segments on the main axis of the mesh fibers, and selects the appropriate extrusion time, extrusion rate, light intensity of the ultraviolet polymerization system, and motion speed of the three-dimensional motion platform for the digital fluid extrusion system.

[0012] Furthermore, the three-phase material supply system includes:

[0013] Internal phase pumping system, intermediate phase pumping system and external phase pumping system;

[0014] The internal phase pumping system, the intermediate phase pumping system, and the external pumping system all consist of the same hardware, including:

[0015] Fixed brackets are used to secure other hardware components in a three-phase material supply system.

[0016] The material pumping system pumps the material to the digital flow extrusion system at specified times and speeds.

[0017] The storage container is used to hold the internal phase, intermediate phase and external phase material system, and to supply it to the digital flow extrusion system through the material supply channel in a timely manner.

[0018] The material supply channel connects to the accumulator in the three-phase material supply system at one end and to the digital flow extrusion system at the other end, enabling the pumping of material between the two systems of the 3D printing device.

[0019] Furthermore, the hardware physical design of the digital fluidic extrusion system includes the size, shape, and layout of the channels. These designs ensure the positional distribution and size of the material during the extrusion process. Secondly, by rationally selecting process parameters, such as extrusion time and speed, the fiber diameter, spindle geometry, and distribution along the fiber can be further adjusted, thereby increasing the biomimetic spiderweb design and achieving efficient water collection. Its hardware components include:

[0020] The protective housing is designed to protect the internal components of the digital fluidized extrusion system from external environmental interference and damage. Internally, it contains three circular coaxial channels for pumping material: an outer phase capillary channel, a mesophase capillary channel, and an inner phase capillary channel.

[0021] The inner phase capillary channel is used to receive the inner phase material system of the three-phase material supply system. After the outer phase and intermediate phase material systems converge after the material extruder, they are deposited on the three-dimensional motion platform. Its inner pore diameter is about 80-300μm and the pipe wall thickness is 50-100μm.

[0022] Mesophase capillary channels are used to receive the mesophase material system from the three-phase material supply system. After converging with the outer and inner phase material systems at the material extruder, the mesophase material system is deposited on a three-dimensional motion platform. The outer channel is coaxial with the inner channel but at a different height, completely enclosing the inner channel to facilitate the formation of spindle-shaped droplets. The inner diameter is approximately 120-400 μm, the wall thickness is 50-100 μm, and the outlet of the mesophase capillary is 20-80 μm longer than that of the inner phase capillary.

[0023] The external phase capillary is used to receive the external phase material system from the three-phase material supply system, allowing it to converge with the mesophase and internal phase material systems after being extruded from the material extruder, and then deposit the entire system onto a three-dimensional motion platform. It is coaxial with but not at the same height as the mesophase capillary. The inner diameter of the external phase capillary is approximately 580-700 μm, the wall thickness is 100-300 μm, and the outlet of the external phase capillary is 20-80 μm shorter than that of the mesophase capillary.

[0024] The coaxial extrusion head is composed of inner phase capillary channels, intermediate phase capillary channels, and outer phase capillary channels. When the inner phase, intermediate phase, and outer phase material system are extruded simultaneously, the intermediate phase covering the inner phase flows into the immiscible outer phase. The intermediate phase is emulsified and continuously broken into droplets, forming a series of droplet knots on the surface of the inner phase. During this process, under the balance of the shear force pushing the knot forward by the outer phase fluid and the surface tension of the inner phase backward, the droplet knots form a spindle shape and form a co-laminar flow state, which is deposited on the three-dimensional motion platform.

[0025] Further, the ultraviolet polymerization system includes:

[0026] The ultraviolet light system, installed inside the light-shielding device, provides all-around illumination to improve polymerization efficiency and is used to polymerize and cure materials extruded by digital fluid control extrusion systems.

[0027] The light-shielding device is surrounded by UV-filtering glass on all four sides, which is used to fully improve the efficiency of ultraviolet light polymerization and achieve the effects of protection and efficiency enhancement.

[0028] Furthermore, the three-dimensional motion platform includes:

[0029] A three-dimensional motion platform software system is used to control the free movement of the three-dimensional motion platform hardware system on the x-axis, y-axis, and z-axis.

[0030] The hardware system of the three-dimensional motion platform is used to realize the physical and kinematic basis of the motion of the three-dimensional motion platform, and realizes the movement of the three-dimensional motion platform under the control of the software system of the three-dimensional motion platform.

[0031] Further explanation: The 3D printing method for intelligent biomimetic spindle-shaped mesh structures for efficient water collection includes:

[0032] S101, Preparation of the material system

[0033] Internal phase material system: Dissolve 2%-2.5% (w / v) sodium alginate in water to obtain a sodium alginate gel solution. This solution is used to ionically crosslink with calcium ions in the intermediate phase material system to generate calcium alginate hydrogel microfibers.

[0034] Mesophase material system: An intermediate phase is obtained by mixing 2%-3% CaCl2 (w / v) dissolved in water to obtain an aqueous solution of CaCl2, 20%-24% (w / v) of the hydrogel precursor N-isopropylacrylamide, and 1%-1.5% (v / v) of the photoinitiator 2-hydroxy-2-methylpropenone in a 1:1:1 ratio. The spindle-shaped nodes formed after emulsification with the external phase material system can be cured under ultraviolet light.

[0035] External phase material system: n-hexadecane. Used to emulsify mesophase material systems, forming spindle nodes on the surface of internal phase microfibers.

[0036] S102, additive manufacturing with a microstructured biomimetic surface, specifically includes:

[0037] Step 1: Construct a material model. Based on the surface requirements for fog capture and droplet manipulation, design a macroscopic model and a microscopic spindle segment distribution, specifically including the macroscopic biomimetic surface shape, local spindle segment size distribution, and spacing.

[0038] Step 2: Additive manufacturing intelligent process programming. Based on the reverse processing in Step 1, the printing parameters of the 3D printing device are obtained, including the printing path, pumping time and pumping speed of the inner phase, intermediate phase, and outer phase material system.

[0039] Step 3: Material preparation. The inner phase, intermediate phase, and outer phase are loaded into the storage container 13 for the preparation of the biomimetic surface.

[0040] Step 4: Additive manufacturing of the biomimetic spindle joint structure. The printing process parameters obtained in Step 2 are input into the 3D printing device mentioned above. Under the control of the intelligent control system 5, the real-time working status of the digital fluid extrusion system 2 and the three-dimensional motion platform 4 is controlled to manufacture a biomimetic surface containing a designed microstructure.

[0041] In the digital flow control extrusion system, the hardware design of the outer phase capillary 22, the middle phase capillary 23 and the inner phase capillary 24 is mutually enclosed and coaxial to obtain the core-sheath co-laminar flow state.

[0042] The extrusion speed of the internal phase capillary channel 24 in the digital fluid control extrusion system is 0.1-1 ml / min;

[0043] In the digital flow control extrusion system, the mesophase capillary 23 and the inner phase capillary 24 are coaxial and in the same direction, and are extruded at an extrusion speed of 1-1.5 ml / min.

[0044] In the digital flow control extrusion system, the external phase flows between the external phase capillary 22 and the mesophase capillary 23, and the extrusion speed is 10-15 ml / min.

[0045] The digital fluid control extrusion system 2 allows for real-time adjustment of extrusion speeds during operation, enabling control of the spindle segment size and spacing by adjusting the extrusion speeds of the mesophase and outer phase material systems. The spindle segment size is positively correlated with the extrusion speed of the mesophase material system and negatively correlated with the extrusion speed of the outer phase material system, while the spindle segment spacing exhibits the opposite correlation.

[0046] The three-dimensional motion platform 4 moves at a speed of 0.1-10 mm / s.

[0047] S103, UV polymerization treatment: The printing process is carried out under UV polymerization conditions, allowing for initial polymerization of the structure during extrusion at a power of 300-600W. Subsequently, the spiderweb-like structure on the 3D motion platform 4 is further treated with UV light for 20-100 minutes at a power of 100-500W. Ultimately, the biomimetic surface is formed.

[0048] The prepared spider web-like structure captures water droplets on the spindle segments. As the temperature increases (temperature range of 40-60℃), the spindle segments shrink significantly, and the originally adhered water droplets gradually fall off, converge, and move in a directional manner, thus achieving the functions of efficient water collection and liquid manipulation.

[0049] This invention has the following advantages:

[0050] In the first aspect, this invention develops a 3D printing device and method for a biomimetic surface with mist collection and droplet manipulation functions, which can directly realize the spindle segment structure required for efficient water collection. At the same time, the selection of hydrophilic materials also greatly improves the efficiency of mist collection. The operation is simple and is expected to achieve large-scale production.

[0051] Secondly, this invention proposes a 3D printing method and apparatus for a biomimetic surface with mist collection and droplet manipulation functions. Through the hardware design of a coaxial extrusion system comprising outer, intermediate, and inner phase capillary channels, combined with the control of the flow rate of each phase channel, real-time adjustment of the size and spacing of the microfiber spindle segments during the printing process is achieved. By designing and printing these gradients in the size and spacing of these microstructures, directional liquid transport can be realized.

[0052] Thirdly, in the 3D printing device and method for a biomimetic surface with mist collection and droplet manipulation functions proposed in this invention, the spindle segment is a smart material. As the ambient temperature increases, the size of the spindle segment can be reduced, accelerating the droplet detachment and movement, thereby further improving the droplet collection efficiency. Attached Figure Description

[0053] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0054] Figure 1 This is a schematic diagram of the system configuration of the present invention.

[0055] Figure 2 This invention relates to a 3D printing device for a biomimetic surface with mist collection and droplet manipulation functions.

[0056] Figure 3 The present invention relates to a digital fluid extrusion system for a 3D printing method and apparatus for a biomimetic surface with mist collection and droplet manipulation functions.

[0057] Figure 4 This invention relates to a 3D printing method and apparatus for a biomimetic surface with fog collection and droplet manipulation functions, and includes a magnified microscopic image of the biomimetic surface.

[0058] The reference numerals in the figure are:

[0059] Three-phase material supply system 1. Digital flow control extrusion system 2. Ultraviolet polymerization system 3. Three-dimensional motion platform 4. Intelligent control system 5;

[0060] 11. Fixed support; 12. Material pumping system; 13. Material storage tank; 14. Material supply channel;

[0061] 21. Protective shell; 22. Outer phase capillary; 23. Intermediate phase capillary; 24. Inner phase capillary; 25. Coaxial extruder;

[0062] 31. Ultraviolet light system; 32. Light-shielding device.

[0063] Specific Implementation Cases

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] This invention solves the problems of current water collection devices relying solely on gravity for droplet detachment, lacking an intelligent active removal mechanism, and being difficult and complex to operate, thus greatly improving the efficiency of mist collection and high-efficiency water collection. For detailed technical solutions, please refer to [link to technical specifications]. Figure 1 As shown, a 3D printing device with a biomimetic surface featuring mist collection and droplet manipulation functions includes:

[0066] The three-phase material supply system 1 consists of three material pumping systems, designed to precisely and timed extract and pump multi-material systems into the digital flow control extrusion system;

[0067] The digital fluid extrusion system 2 is the core component of the 3D printing device of this invention. It is connected to the three-phase material supply system 1, which pumps three kinds of materials to different channel inlets of the digital fluid extrusion system 2. The extrusion of the complex digital fluid system is achieved by relying on the hardware physical design of the digital fluid extrusion system 2 and the selection of process parameters.

[0068] The ultraviolet polymerization system 3 irradiates the material extruded by the digital flow control extrusion system 2 from all directions to achieve instantaneous shape fixation of the spindle section structure;

[0069] The three-dimensional motion platform 4, as the basic component of the 3D printing system, controls the movement within the spatial range of the three-dimensional motion platform 4, thereby depositing the coaxially distributed material system extruded by the digital fluid extrusion system onto the molding platform, realizing the three-dimensional molding with a complex macro-micro biomimetic spider web structure.

[0070] The intelligent control system 5 obtains a mesh structure model through reverse design based on the expected function, determines the geometric dimensions and spacing of the spindle nodes on the main axis of the mesh fiber, selects the appropriate extrusion time, extrusion rate, light intensity of the ultraviolet polymerization system 3, and movement speed of the three-dimensional motion platform 4.

[0071] Furthermore, the three-phase material supply system 1 includes:

[0072] Internal phase pumping system, intermediate phase pumping system and external phase pumping system;

[0073] The internal phase pumping system, the intermediate phase pumping system, and the external pumping system all consist of the same hardware, including:

[0074] Fixed bracket 11 is used to fix other component hardware in the three-phase material supply system 1;

[0075] The material pumping system 12 pumps the material to the digital flow extrusion system 2 at a specified time and speed;

[0076] The storage container 13 is used to hold the internal phase, intermediate phase and external phase material system, and to supply it to the digital flow extrusion system 2 through the material supply channel 14 in a timely manner.

[0077] The material supply channel 14 is connected at one end to the storage device 13 in the three-phase material supply system and at the other end to the digital flow extrusion system 2, realizing the pumping of material in the two major systems of the 3D printing device.

[0078] Furthermore, the hardware physical design of the digital flow control extrusion system 2 includes the size, shape, and layout of the channels, such as... Figure 2 As shown. Its hardware components include:

[0079] The protective housing 21 is designed to protect the internal components of the digital fluid extrusion system 2 from interference and damage from the external environment. It contains three circular coaxial channels for pumping material: an outer phase capillary channel 22, an intermediate phase capillary channel 23, and an inner phase capillary channel 24.

[0080] The inner phase capillary channel 24 is used to receive the inner phase material system of the three-phase material supply system. After the outer phase and intermediate phase material systems converge after the material extrusion head, they are deposited on the three-dimensional motion platform 4. Its inner diameter is about 80 μm and the pipe wall thickness is 50 μm.

[0081] Mesophase capillary 23 is used to receive the mesophase material system from the three-phase material supply system. After converging with the outer and inner phase material systems at the material extruder, it is deposited on the three-dimensional motion platform 4. It is coaxial with the inner pipe but at a different height. The outer pipe completely wraps around the inner pipe to facilitate the formation of spindle-shaped droplets. The inner diameter is about 120 μm and the pipe wall thickness is 50 μm. The outlet of mesophase capillary 23 is 20 μm longer than that of inner phase capillary 24.

[0082] The outer phase capillary 22 is used to receive the outer phase material system of the three-phase material supply system, allowing it to converge with the mesophase and inner phase material systems after being extruded by the material extruder, and then deposit the entire system onto the three-dimensional motion platform 4. It is coaxial with but not at the same height as the mesophase capillary 23. The outer phase capillary 22 has an inner diameter of approximately 580 μm, a wall thickness of 100 μm, and its outlet is 20 μm shorter than that of the mesophase capillary.

[0083] The coaxial extrusion head 25 is composed of inner phase capillary channel 24, intermediate phase capillary channel 23, and outer phase capillary channel 22. When the material system of inner phase, intermediate phase and outer phase is extruded at the same time, the intermediate phase covering the inner phase flows into the immiscible outer phase. The intermediate phase is emulsified and continuously broken into droplets to form a series of droplet knots on the surface of the inner phase. In this process, under the balance of the shear force pushing the knot forward by the outer phase fluid and the surface tension of the inner phase backward, the droplet knots form a spindle shape and form a co-laminar flow state, which is deposited on the three-dimensional motion platform 4.

[0084] Furthermore, the ultraviolet polymerization system 3 includes:

[0085] The ultraviolet light system 31 is installed inside the light-shielding device, providing all-around light to improve polymerization efficiency and is used to polymerize and cure extruded materials in a digital fluid control extrusion system.

[0086] The light-shielding device 32 is surrounded on all four sides by ultraviolet-filtering glass, which is used to fully improve the ultraviolet light polymerization efficiency and achieve the effects of protection and efficiency enhancement.

[0087] Furthermore, the three-dimensional motion platform 4 includes:

[0088] A three-dimensional motion platform software system is used to control the free movement of the three-dimensional motion platform hardware system on the x-axis, y-axis, and z-axis.

[0089] The hardware system of the three-dimensional motion platform is used to realize the physical and kinematic basis of the motion of the three-dimensional motion platform, and realizes the movement of the three-dimensional motion platform under the control of the software system of the three-dimensional motion platform.

[0090] Further explanation: The 3D printing method for intelligent biomimetic spindle-shaped mesh structures for efficient water collection includes:

[0091] S101, Preparation of the material system

[0092] Internal phase material system: 2% (w / v) sodium alginate was dissolved in water to obtain a sodium alginate gel solution. This solution was used to ionically crosslink with calcium ions in the intermediate phase material system to generate calcium alginate hydrogel microfibers.

[0093] Mesophase material system: An intermediate phase was obtained by mixing 2% CaCl2 (w / v) dissolved in water to obtain an aqueous solution of CaCl2, 22% (w / v) hydrogel precursor N-isopropylacrylamide, and 1% (v / v) photoinitiator 2-hydroxy-2-methylpropenone in a 1:1:1 ratio. The spindle-shaped nodes formed after emulsification with the external phase material system can be cured under ultraviolet light.

[0094] External phase material system: n-hexadecane. Used to emulsify mesophase material systems, forming spindle nodes on the surface of internal phase microfibers.

[0095] S102, additive manufacturing with a microstructured biomimetic surface, specifically includes:

[0096] Step 1: Construct a material model. Based on the surface requirements for fog capture and droplet manipulation, design a macroscopic model and a microscopic spindle segment distribution. Specifically, this includes a macroscopic network structure model, local spindle segment size distribution, and spacing, such as... Figure 4 As shown;

[0097] Step 2: Additive manufacturing intelligent process programming. Based on the reverse processing in Step 1, the printing parameters of the 3D printing device are obtained, including the printing path, pumping time and pumping speed of the inner phase, intermediate phase, and outer phase material system.

[0098] Step 3: Material preparation. The inner phase, intermediate phase, and outer phase are loaded into the storage container 13 for the preparation of the spider web-like structure.

[0099] Step 4 involves additive manufacturing of the biomimetic spindle segment structure. The printing process parameters obtained in Step 2 are input into the aforementioned 3D printing device. Under the control of the intelligent control system 5, the real-time operating status of the digital fluid extrusion system 2 and the three-dimensional motion platform 4 is controlled to manufacture a spiderweb-like structure containing a designed spindle segment distribution. Figure 3 As shown.

[0100] The extrusion speed of the internal phase capillary channel 24 in the digital fluid control extrusion system 2 is 1 ml / min;

[0101] In the digital flow control extrusion system 2, the mesophase capillary 23 and the inner phase capillary 24 are coaxial and in the same direction, and are extruded at an extrusion speed of 0.5-1.5 ml / min. The extrusion speed is adjusted in real time during the extrusion process.

[0102] In the digital flow control extrusion system 2, the external phase flows between the external phase capillary 22 and the mesophase capillary 23, and the extrusion speed is 15 ml / min.

[0103] The moving speed of the three-dimensional motion platform 4 is 10 mm / s;

[0104] S103, UV polymerization treatment: The printing process is carried out under UV polymerization conditions, allowing for initial polymerization of the structure during extrusion at a power of 500W. Subsequently, the spiderweb-like structure on the 3D motion platform 4 is further treated with UV light for 50 minutes at a power of 300W. Finally, the spiderweb-like structure is formed.

[0105] The biomimetic surface obtained in this process captures mist and gathers it into droplets at the spindle joint. As the temperature increases (to 50°C), the spindle joint shrinks significantly, and the originally adhered water droplets gradually fall off and gather, thus achieving the function of efficient water collection.

Claims

1. A 3D printing device with a biomimetic surface featuring mist collection and droplet manipulation functions, characterized in that, include: The three-phase material supply system (1) consists of three material pumping systems, designed to precisely and timed extract and pump a multi-material system into a digital flow control extrusion system. The digital fluid extrusion system (2) is the core component of the 3D printing device. It is connected to the three-phase material supply system (1) to pump three kinds of materials to different channel inlets of the digital fluid extrusion system (2). It relies on the hardware physical design of the digital fluid extrusion system combined with the selection of process parameters to realize the extrusion of complex structured material systems. The ultraviolet polymerization system (3) irradiates the structured system extruded by the digital flow control extrusion system from all directions to achieve instantaneous shape fixation of the spindle section structure; The three-dimensional motion platform (4), as the basic component of the 3D printing system, controls the movement within the spatial range of the three-dimensional motion platform, thereby depositing the coaxially distributed material system extruded by the digital fluid extrusion system onto the molding platform, realizing the three-dimensional molding with a complex macro-micro biomimetic spider web structure. The intelligent control system (5) obtains the mesh structure model by reverse design according to the expected function, determines the geometric dimensions and spacing of the spindle nodes on the main shaft of the mesh fiber, selects the appropriate extrusion time, extrusion rate of the digital flow control extrusion system, the light intensity of the ultraviolet polymerization system and the movement speed of the three-dimensional motion platform.

2. The 3D printing device with a biomimetic surface having fog collection and droplet manipulation functions as described in claim 1, characterized in that, The three-phase material supply system (1) includes: Internal phase pumping system, intermediate phase pumping system and external phase pumping system; The internal phase pumping system, the intermediate phase pumping system, and the external pumping system all consist of the same hardware, including: Fixed bracket (11), which is used to fix other component hardware in the three-phase material supply system; The material pumping system (12) pumps the material to the digital flow extrusion system at a specified time and speed; The storage container (13) is used to hold the internal phase, intermediate phase and external phase material system and supply it to the digital flow extrusion system through the material supply channel in a timely manner. The material supply channel (14) is connected at one end to the storage device in the three-phase material supply system and at the other end to the digital flow control extrusion system, realizing the pumping of materials in the two major systems of the 3D printing device.

3. The 3D printing device with a biomimetic surface having fog collection and droplet manipulation functions as described in claim 1, characterized in that, The digital flow control extrusion system (2) includes: The protective housing (21) is designed to protect the internal components of the digital fluid extrusion system from interference and damage from the external environment. It contains three circular coaxial channels for pumping material, including an outer phase capillary channel, an intermediate phase capillary channel, and an inner phase capillary channel. The inner phase capillary (24) is used to receive the inner phase material system of the three-phase material supply system. After the outer phase and intermediate phase material system converge after the material extrusion head, it is deposited on the three-dimensional motion platform (4). Its inner diameter is 80-300μm and the pipe wall thickness is 50-100μm. The mesophase capillary (23) is used to receive the mesophase material system of the three-phase material supply system. After the mesophase and inner phase material systems converge after the material extrusion head, they are deposited on the three-dimensional motion platform (4). It is coaxial with the inner pipe but at a different height. The outer pipe completely wraps the inner pipe to facilitate the formation of spindle-shaped droplets. The inner diameter is 120-400μm and the pipe wall thickness is 50-100μm. The outlet of the mesophase capillary (23) is 20-80μm longer than that of the inner phase capillary. The outer phase capillary (22) is used to receive the outer phase material system of the three-phase material supply system, so that it converges with the meso phase and inner phase material system after being extruded by the material extrusion head, and deposits it as a whole on the three-dimensional motion platform (4). It is coaxial with the meso phase capillary but not at the same height. The inner diameter of the outer phase capillary (22) is 580-700μm, the wall thickness is 100-300μm, and the outlet of the outer phase capillary (22) is 20-80μm shorter than that of the meso phase capillary (23). A coaxial extrusion head (25) is composed of an inner phase capillary (24), an intermediate phase capillary (23), and an outer phase capillary (22). When the inner phase, intermediate phase, and outer phase material system are extruded simultaneously, the intermediate phase covering the inner phase flows into the immiscible outer phase. The intermediate phase is emulsified and continuously broken into droplets, forming a series of droplet knots on the surface of the inner phase. During this process, under the balance of the shear force pushing the knot forward by the outer phase fluid and the surface tension of the inner phase surface backward, the droplet knots form a spindle shape and form a co-laminar flow state, which is deposited on the three-dimensional motion platform.

4. The 3D printing device with a biomimetic surface having fog collection and droplet manipulation functions as described in claim 1, characterized in that, The ultraviolet polymerization system (3) includes: The ultraviolet light system (31) is installed inside the light-shielding device. The all-round light illumination improves the polymerization efficiency and is used to polymerize and cure the extruded material of the digital fluid control extrusion system. The light-shielding device (32) is surrounded on all four sides by ultraviolet-filtering glass, which is used to fully improve the efficiency of ultraviolet light polymerization and achieve the effects of protection and efficiency enhancement.

5. The 3D printing device with a biomimetic surface having fog collection and droplet manipulation functions as described in claim 1, characterized in that, The three-dimensional motion platform (4) includes: A three-dimensional motion platform software system is used to control the free movement of the three-dimensional motion platform hardware system on the x-axis, y-axis, and z-axis. The hardware system of the three-dimensional motion platform is used to realize the physical and kinematic basis of the motion of the three-dimensional motion platform, and realizes the movement of the three-dimensional motion platform under the control of the software system of the three-dimensional motion platform.

6. A 3D printing method using the 3D printing apparatus with a biomimetic surface having fog collection and droplet manipulation functions as described in any one of claims 1 to 5, characterized in that, include: S101, Preparation of the material system Inner phase material system: Sodium alginate is dissolved in water to obtain a sodium alginate gel solution with a concentration of 2%-2.5% w / v, which is used to undergo ionic cross-linking with calcium ions in the intermediate phase material system to generate calcium alginate hydrogel microfibers. Mesophase material system: A 2%-3% w / v CaCl2 aqueous solution, a 20%-24% w / v N-isopropylacrylamide hydrogel precursor, and a 1%-1.5% v / v photoinitiator 2-hydroxy-2-methylpropenone are mixed in a 1:1:1 ratio to obtain the mesophase. The spindle joints formed after emulsification with the external phase material system can be cured under ultraviolet light. External phase material system: n-hexadecane, used to emulsify the mesophase material system and form spindle nodes on the surface of the internal phase microfibers; S102, additive manufacturing with a microstructured biomimetic surface, specifically includes: Step 1: Construct a material model. Based on the surface requirements for fog capture and droplet manipulation, design a macroscopic model and a microscopic spindle segment distribution, specifically including the macroscopic biomimetic surface shape, local spindle segment size distribution, and spacing. Step 2: Additive manufacturing intelligent process programming. Based on the reverse processing of Step 1, obtain the printing parameters of the 3D printing device, including the printing path, pumping time and pumping speed of the inner phase, intermediate phase and outer phase material system. Step 3 Material preparation: The inner phase, intermediate phase and outer phase are loaded into the storage container (13) for the preparation of the biomimetic surface; Step 4: Additive manufacturing of the biomimetic spindle joint structure. The printing process parameters obtained in step 2 are input into the above-mentioned 3D printing device. Under the control of the intelligent control system (5), the real-time working status of the digital flow extrusion system (2) and the three-dimensional motion platform (4) is controlled to manufacture the biomimetic surface containing the designed microstructure. In the digital flow control extrusion system, the external phase capillary (22), the intermediate phase capillary (23) and the internal phase capillary (24) are designed to be mutually enclosed and coaxial in order to obtain a core-sheath co-laminar flow state. The extrusion speed of the internal phase capillary channel (24) in the digital fluid control extrusion system is 0.1-1 ml / min; In the digital flow control extrusion system, the mesophase capillary (23) and the inner phase capillary (24) are coaxial and in the same direction, and are extruded at an extrusion speed of 1-1.5 ml / min. In the digital flow control extrusion system, the external phase flows between the external phase capillary (22) and the mesophase capillary (23) in the external phase capillary (22), and the extrusion speed is 10-15 ml / min; The digital flow control extrusion system (2) can adjust the extrusion speed in real time during operation. By adjusting the extrusion speed of the mesophase and outer phase material systems, the size and spacing of the spindle section can be controlled. The size of the spindle section is positively correlated with the extrusion speed of the mesophase material system and negatively correlated with the extrusion speed of the outer phase material system, while the spacing of the spindle section is the opposite. The moving speed of the three-dimensional motion platform (4) is 0.1-10 mm / s; S103, UV light polymerization treatment, the printing process is carried out under UV light polymerization conditions, the structure can be initially polymerized during the extrusion process, the power is 300-600W, then the spider web structure on the three-dimensional motion platform (4) is further treated with ultraviolet light, the UV irradiation time is 20-100min, the power is 100-500W, and finally, the biomimetic surface is formed. The prepared spider web-like structure captures water droplets on the spindle segments. As the temperature increases (ranging from 40 to 60°C), the spindle segments shrink significantly, and the originally adhered water droplets gradually fall off, converge, and move in a directional manner, thus achieving efficient water collection and liquid manipulation.

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