Method for regulating directional transport of liquid in one dimension using photocured 4D printed symmetric morphological surface array structure

Abstract

The application discloses a kind of light-cured 4D printing symmetrical morphology surface array structure for the adjustment method of liquid one-dimensional arbitrary direction directional transport, the method comprises the following steps: step 1, preparation of resin with the preparation of DLP type 4D printing performance;Step 2, the design and construction of symmetrical morphology structure unit;Step 3, the 3D model construction of the surface array of symmetrical morphology structure unit;Step 4, 4D printing is carried out to the surface array structure of the 3D model construction;Step 5, surface array structure thermal stimulation response 4D change and liquid directional transport direction change and control.The symmetrical morphology surface array structure based on light-cured 4D printing technology construction, successfully realized the long-distance, directional transport of one-dimensional arbitrary adjustment of low surface tension liquid, and shows broad application potential in microfluidic chip, biochemical microreactor and other frontier fields.

Description

Technical Field

[0001] This invention belongs to the field of intelligent transportation technology and relates to a one-dimensional directional transportation method for liquids. Specifically, it relates to the preparation of a symmetrical surface array structure of photopolymer 4D printing and the adjustment method for the directional transportation of liquids in any one-dimensional direction on its surface. Background Technology

[0002] Controlling the directional, long-distance transport of liquids on open surfaces has significant applications in microfluidics, industrial condensation, and chemical reactions. Currently, most open-surface liquid transport interfaces based on chemical gradients, structural gradients, or capillary forces are still limited to a single, predetermined transport direction. Their core bottleneck lies in the lack of dynamically adjustable response capabilities, essentially relying on static and non-reconfigurable geometric gradients. Once the interface structure is fabricated, the transport path is fixed and cannot be adjusted in real time according to actual needs or environmental changes. Furthermore, existing strategies still have limitations in terms of transport distance, making it difficult to meet the demands of long-distance transport in practical applications. Summary of the Invention

[0003] This invention provides a method for regulating the directional transport of liquids in any one-dimensional direction using a photopolymerization 4D printed symmetrical surface array structure. Based on photopolymerization 3D printing (DLP) technology, this method designs an array structure composed of repeatedly arranged symmetrical structural units, enabling flexible control of directional liquid transport in any one-dimensional direction. By combining the intelligent property of materials—shape memory deformation capability—with intelligent manufacturing processes (DLP), controllable morphological changes of the surface array structure under thermal stimulation response are achieved, falling within the typical scope of 4D printing technology. The symmetrical structural units designed in this invention can produce asymmetrical morphological differences driven by the shape memory effect, and their deformation direction is adjustable. Combined with the collaborative 4D deformation behavior of the structural units in the array, the system can guide low surface energy liquids to achieve directional transport along a preset deformation direction, while maintaining the liquid's pinning state on the non-deformation side. This structure achieves flexible directional control and arbitrary start / stop of liquids during directional transport, providing an innovative method for intelligent liquid transport on open surfaces.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for regulating the one-dimensional directional transport of liquids in arbitrary directions using a photopolymerization 4D printed symmetrical surface array structure includes the following steps:

[0006] Step 1: Preparation of resin with DLP-type 4D printing performance:

[0007] The resin comprises a difunctional acrylate crosslinking agent, a monofunctional acrylate diluent, photoinitiator 819, and a light absorber, Sudan III. The mass ratio of the difunctional acrylate crosslinking agent to the monofunctional acrylate diluent is 20-40:60-80. The acrylate crosslinking agent is one of the following: polyurethane-acrylate crosslinking agents CN996, CN966, CN9021, polyethylene glycol diacrylate, and tripropylene glycol diacrylate. The monofunctional acrylate diluent is one or more of isobornyl methacrylate (IBOA), hydroxyethyl acrylate (HEA), 4-acryloylmorpholine, and N-vinylpyrrolidone. The photoinitiator is photoinitiator 819, used at a concentration of 0.5-1.5% of the total mass of the difunctional acrylate crosslinking agent and the monofunctional acrylate diluent. wt%; the light absorber is Sudan III, and the amount used is 0.01~0.05wt% of the total mass of the difunctional acrylate crosslinking agent and the monofunctional acrylate diluent; place the acrylate crosslinking agent and the monofunctional acrylate diluent in a container and mix them evenly. Add the photoinitiator and the light absorber under light-protected conditions and mix evenly. Store in a light-protected place.

[0008] Step 2: Design and construction of symmetrical structural units:

[0009] Using 3D modeling software, the structural units are modeled in 3D to construct a pointed pyramidal structure with full symmetry. The structural unit consists of two parts: a prism structure in the lower half and a pyramidal structure in the upper half. The base of the prism structure has a side length of... A square, with a central platform having a side length of [missing information]. a square, The base platform of the pyramid structure has a side length of... A square with a pointed pyramidal top; the height of the prism structure is... The height of the pyramid structure is The angle between the lateral edge and the base of the prism is ; =0.5~1mm, =0.94~3.76mm, =1.25~5mm, =1~4mm, ,For example: , , , , ; , , , , ; , , , , ; , , , , ;

[0010] Step 3: Construction of a 3D model of the surface array of symmetrical morphological structural units:

[0011] A rectangular base plate model is constructed using 3D modeling software, and then assembled and linearly arrayed with the pointed pyramidal structure with full symmetry designed in step 2 to obtain a surface array structure assembly model, wherein the spacing between adjacent structural units is 3.0 mm.

[0012] Step 4: 4D print the surface array structure of the constructed 3D model:

[0013] The surface array structure assembly model was imported into a 3D printer and 4D printed using the resin prepared in step 1. The 4D printing parameters were as follows: the resin was cured layer by layer to the upper platform under a 385nm light source, and the height of each cured layer was 0.5~0.1mm.

[0014] Step 5: 4D changes in the thermal stimulus response of the surface array structure and the transformation and control of the directional transport direction of liquid:

[0015] Step 5-1: Heat the printed model to its glass transition temperature (T). g The above steps are then performed by tilting the printed model at a 60° angle in one direction and cooling it to room temperature to fix it, thus realizing the 4D change of the surface array structure in response to thermal stimulation.

[0016] Step 5-2: Inject a low surface tension (22.1~24 mN / m) liquid into the surface of the deformed model obtained in step 5-1. The low surface tension liquid spreads along its structural contour and is transported in a directional manner in the deformation direction.

[0017] Step 5-3, Changing the direction of liquid transport: Heat the deformable model to the glass transition temperature (T). g The above steps restore the model to its initial shape. Then, the printed model is pressed down and tilted 60° in the opposite direction and cooled to room temperature to set.

[0018] Step 5-4: Inject a low surface tension liquid into the surface of the deformed model obtained in step 5-3. The low surface tension liquid spreads along its structural contour, thereby changing the transport direction.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention utilizes a symmetrical surface array structure constructed using photopolymerization 4D printing technology, successfully achieving long-distance, directional transport of low-surface-tension liquids with arbitrary one-dimensional adjustment. Compared to existing technologies, this structure's advantage lies in combining a symmetrical surface array with 4D printing, granting highly flexible control over the one-dimensional transport direction. Furthermore, leveraging the shape memory effect of thermal stimulus response, the shape of the surface array structure can be controllably changed, fixed, restored, and repeatedly deformed, thus enabling the liquid transport direction to possess programmable, segmented, adjustable, and real-time controllable characteristics. This 4D-printed surface array structure, with its excellent liquid directional transport performance and flexible controllability, demonstrates broad application potential in cutting-edge fields such as microfluidic chips and biochemical microreactors. Attached Figure Description

[0021] Figure 1 The molecular formula and structural formula of 4D printing resin formulation;

[0022] Figure 2 A shape memory effect diagram of the polymer after the 4D printing resin has cured.

[0023] Figure 3 These are the three views of the structural unit;

[0024] Figure 4 A 3D model of a surface array of symmetrical structural units;

[0025] Figure 5 A printed image of a surface array of symmetrical structural units;

[0026] Figure 6 4D printed deformation diagram of a surface array of symmetrical structural units;

[0027] Figure 7 This refers to the directional transport of ethanol along the deformation direction of the surface array of symmetrical structural units;

[0028] Figure 8 This refers to the directional transport of ethanol along the deformation direction of the surface array of symmetrical structural units at arbitrary positions. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0030] Example 1: Directional transport of ethanol using 4D-printed surface array structures with low glass transition temperature

[0031] Step 1: The 4D printing resin contains a bifunctional acrylate crosslinking agent, a monofunctional acrylate diluent, a photoinitiator, and a light absorber. 40 wt% of the crosslinking agent polyurethane-acrylate CN996, 40 wt% isobornyl methacrylate (IBOA), and 20 wt% hydroxyethyl acrylate (HEA) are placed in a container and mechanically stirred for 6 hours to ensure uniform mixing. Subsequently, under light-protected conditions, 1 wt% of the total polymer mass of the photoinitiator 819 and 0.01 wt% of the light absorber Sudan are added. The mixture is then sonicated in an ice-water bath for 15 minutes until completely dissolved and stored in the dark. After curing under 385nm UV light for 5 minutes, the glass transition temperature is 65℃. The prepared resin exhibits good shape memory effect after curing. Its molecular formula and structural formula are as follows: Figure 1 As shown, the shape memory effect is as follows Figure 2 As shown.

[0032] Step 2: Create a part (Part 1) using Solidworks software, construct a plane (Plane 1), and create a square sketch with a bottom side length of 1mm within this plane. Figure 1 Construct another plane (plane 2) at a perpendicular distance of 2.5mm from the original plane, with the two planes being parallel to each other; create a square sketch with a side length of 1.88mm in plane 2. Figure 2 The two sketches are positioned such that their center points are on a straight line and the straight-line distance between their center points is 2.5 mm; for the sketches... Figure 1 ,Grass Figure 2 Lofting the bosses yields a three-dimensional structure (Structure 1). At a distance from the grass... Figure 2 Construct plane 3 at a distance of 2mm (vertical distance) from the existing plane, with the two planes being parallel; in plane 3, at a distance of 2mm (vertical distance) from the grass Figure 2 Create a center point sketch 2mm from the center point (sketching) Figure 3 ), the grass Figure 3 with grass Figure 2 Loft the boss to obtain the 3D structure (Structure 2). Merge Structure 1 and Structure 2 to obtain the 3D model of the structural unit, whose three views are as follows. Figure 3 As shown.

[0033] Step 3: Use Solidworks software to create the part (Part 2) and construct plane 1. Within this plane, create a sketch with a length of 50mm and a width of 8mm. Figure 1 ). For grass Figure 1 Perform a boss stretching operation with a feature value of 1.5mm to obtain a cuboid part with a length of 50mm, a width of 8mm, and a height of 1.5mm; create a new draft on plane 1. Figure 2Create a square with sides of 1mm centered at the plane's center point and save it with a filename ending in .SLDPRT. Create a new assembly using Solidworks and insert Part 1 and Part 2. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) Figure 1 The four sides of the grass in part 2 Figure 2 Establish overlapping mating relationships between the four sides of part 1, and linearly array part 1 with the length of part 2 as the direction, to obtain... Figure 4 The 3D model of the array of symmetrical structural units shown is saved as a file with the .STL extension.

[0034] Step 4: Import the .STL file of the assembly from Step 3 into the slicing software for slicing. The model slice layer height is 0.1mm. Pour the resin from Step 1 into the resin tank of the DLP 3D printer, import the slice file into the 3D printer, and perform 3D printing. The printing parameters are as follows: printing at 25℃ under a 385nm wavelength light source with a light source power of 1000W; the first layer curing time is 30s, the substrate curing layers are 3, and the lifting height of each layer is 5mm; subsequently, each layer curing time is 15s. After printing, the printed array structure is ultrasonically cleaned in ethanol for 5 minutes to remove unpolymerized components from the surface; then, the printed array structure is post-treated in a 385nm ultraviolet curing chamber for 15 minutes to ensure complete curing. The 3D printed object is shown below. Figure 5 As shown.

[0035] Step 5: Heat the printing model to 95℃ (T g +10℃ and hold for 15 minutes to ensure the material modulus is sufficiently low. Tilt the printed model 60° in one direction and cool to room temperature for 5 minutes to achieve 4D thermal stimulus response changes in the surface array structure, such as... Figure 6 As shown. Ethanol is injected into the deformed array surface, spreading along its structural contour and being transported directionally in the deformation direction, as... Figure 7 As shown. Further, the direction of liquid transport is changed. The deformable model is heated to the glass transition temperature (T). g The above steps restore the model to its initial shape. Then, the printed model is tilted and deformed at a 60° angle in the opposite direction and cooled to room temperature to set. After injection onto the deformed array surface, ethanol spreads in the opposite direction, completing the change in liquid transport direction, as shown below. Figure 8 As shown.

[0036] Example 2: Directional transport of 80°C dimethyl silicone oil in 4D printed surface array structures with high glass transition temperature

[0037] The difference between this embodiment and Embodiment 1 is that:

[0038] Step 1: The 4D printing resin contains a bifunctional acrylate crosslinking agent, a monofunctional acrylate diluent, a photoinitiator, and a light absorber. 40 wt% of the crosslinking agent tripropylene glycol diacrylate, 40 wt% of N-vinylpyrrolidone, and 20 wt% of isobornyl methacrylate (IBOA) are placed in a container and mechanically stirred for 6 hours to ensure uniform mixing. Subsequently, under light-protected conditions, 1 wt% of the total polymer mass of photoinitiator 819 and 0.01 wt% of the light absorber Sudan are added. The mixture is then sonicated in an ice-water bath until completely dissolved and stored in the dark. After curing under 385 nm UV light for 5 minutes, the resulting glass transition temperature is 65°C.

[0039] Step 5: Heat the printed model to 120℃ (T g +10℃ and held for 15 minutes to ensure the material modulus is sufficiently low. The printed model is then tilted and deformed at 60° in one direction and cooled to room temperature for 5 minutes to achieve a 4D thermal stimulus response of the surface array structure. Dimethyl silicone oil is injected into the deformed array surface, spreading along its structural contour and being transported directionally in the deformation direction. Further, the transport direction is changed. The deformed model is heated to its glass transition temperature (T0). g The above steps restore the model to its initial shape. The printed model is then tilted and deformed at a 60° angle in the opposite direction and cooled to room temperature to set. After injection onto the deformed array surface, dimethyl silicone oil is spread in the opposite direction, completing the change in transport direction.

Claims

1. A method for adjusting a photopolymerized 4D printed symmetrical surface array structure for one-dimensional directional transport of liquid in any direction, characterized in that... The method includes the following steps: Step 1: Prepare resin with DLP-type 4D printing performance: The difunctional acrylate crosslinking agent and the monofunctional acrylate diluent are mixed evenly in a container. Under light-protected conditions, the photoinitiator and light absorber are added and mixed thoroughly. The mixture is then stored in a light-protected place. The mass ratio of the difunctional acrylate crosslinking agent to the monofunctional acrylate diluent is 20-40:60-80. The amount of photoinitiator is 0.5-1.5 wt% of the total mass of the difunctional acrylate crosslinking agent and the monofunctional acrylate diluent; the amount of light absorber is 0.01-0.05 wt% of the total mass of the difunctional acrylate crosslinking agent and the monofunctional acrylate diluent. Step 2: Design and construction of symmetrical structural units: Using 3D modeling software, structural units are modeled in 3D to construct a pointed pyramidal structure with full symmetry. The structural unit consists of two parts: a prism structure in the lower half and a pyramidal structure in the upper half. The base of the prism structure has a side length of... A square, with a central platform having a side length of [missing information]. a square, The base platform of the pyramid structure has a side length of... A square with a pointed pyramidal top; the height of the prism structure is... The height of the pyramid structure is The angle between the lateral edge and the base of the prism is ; =0.5~1mm, =0.94~3.76mm, =1.25~5mm, =1~4mm, ; Step 3: Construction of a 3D model of the surface array of symmetrical morphological structural units: A rectangular base plate model is constructed using 3D modeling software, and then assembled and linearly arrayed with the pointed pyramidal structure with full symmetry designed in step 2 to obtain a surface array structure assembly model. Step 4: 4D print the surface array structure of the constructed 3D model: The surface array structure assembly model was imported into a 3D printer, and 4D printing was performed using the resin prepared in step 1. The 4D printing parameters were as follows: the resin was cured layer by layer to the upper platform under a 385nm light source, and the height of each cured layer was 0.5~0.1mm. Step 5: 4D changes in the thermal stimulus response of the surface array structure and the transformation and control of the directional transport direction of liquid: Step 5-1: Heat the printed model to above the glass transition temperature, then tilt and deform the printed model at 60° in one direction, and cool it to room temperature to fix it, thus realizing the 4D change of the surface array structure in response to thermal stimulation. Step 5-2: Inject a low surface tension liquid into the surface of the deformed model obtained in step 5-1. The low surface tension liquid spreads along its structural contour and is transported in a directional manner in the deformation direction. Step 5-3, Change of liquid transport direction: Heat the deformed model above the glass transition temperature to restore it to its initial shape, then press the printed model down and tilt it 60° in the opposite direction and cool it to room temperature to fix it. Step 5-4: Inject a low surface tension liquid into the surface of the deformed model obtained in step 5-3. The low surface tension liquid spreads along its structural contour, thereby changing the transport direction.

2. The method for adjusting the one-dimensional directional transport of liquid in arbitrary directions using the photopolymerization 4D printed symmetrical surface array structure according to claim 1, characterized in that... In step 1, the bifunctional acrylate crosslinking agent is one of polyurethane-acrylate crosslinking agent CN996, polyethylene glycol diacrylate, and tripropylene glycol diacrylate.

3. The method for adjusting the one-dimensional directional transport of liquid in arbitrary directions using the photopolymerization 4D printed symmetrical surface array structure according to claim 1, characterized in that... In step 1, the monofunctional acrylate diluent is one or more of isobornyl methacrylate and hydroxyethyl acrylate.

4. The method for adjusting the one-dimensional directional transport of liquid in arbitrary directions using the photopolymerization 4D printed symmetrical surface array structure according to claim 1, characterized in that... In step 1, the photoinitiator is photoinitiator 819.

5. The method for adjusting the one-dimensional directional transport of liquid in arbitrary directions using the photopolymerization 4D printed symmetrical surface array structure according to claim 1, characterized in that... In step 1, the light absorber is Sudan III.

6. The method for adjusting the one-dimensional directional transport of liquid in arbitrary directions using the photopolymerization 4D printed symmetrical surface array structure according to claim 1, characterized in that... In step 3, the spacing between adjacent structural units is 3.0 mm.

7. The method for adjusting the one-dimensional directional transport of liquid in arbitrary directions using the photopolymerization 4D printed symmetrical surface array structure according to claim 1, characterized in that... In step 5, the surface tension of the low surface tension liquid is 22.1~24 mN / m.

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