Passive micro-mixer with three-dimensional spiral spherical structure and manufacturing method of passive micro-mixer

Abstract

The invention provides a three-dimensional spiral spherical passive micro-mixer and a manufacturing method thereof. The three-dimensional spiral spherical structure micro-mixer mainly comprises an inlet, an outlet, a spiral mixing channel and a spherical chamber, the mixing performance of the micro-mixer is enhanced mainly according to random irregular movement of spirally rotated liquid in the spherical mixing chamber. The manufacturing method comprises the following steps that a high-precision 3D printer is used for printing an HIPS channel mold and a PLA pouring mold; pDMS is used for pouring the micro-mixer manufactured through 3D printing, and drying and curing are conducted; and punching the PDMS with the channel mold, and putting the PDMS into limonene to be fully soaked until the HIPS is completely dissolved. According to the method, the steps of photoetching and the like on the surface of the PDMS are not needed, so that the technological process is simplified, and the problem of high manufacturing complexity in a traditional method is solved. And meanwhile, integral processing of micro-size particles can be realized in the mixing chamber. In conclusion, the micro-mixer has the advantages of simple process and low cost, and is suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to a three-dimensional spiral spherical structure passive micro-mixer and a manufacturing method thereof Background Art

[0002] With the continuous development of microfluidic technology, the micro-mixer, as a key microfluidic component, is widely used in fields such as chemical analysis, life science, and environmental monitoring. The main function of the micro-mixer is to quickly and uniformly mix different fluids at the micro-scale, thereby improving the reaction efficiency and result accuracy. However, traditional micro-mixers face problems such as low mixing efficiency and long mixing time. Due to the small scale of the microfluidic channel and the fast fluid flow velocity, the mixing between fluid molecules often relies on molecular diffusion, and this diffusion process is usually very slow at the micro-scale. Therefore, how to improve the micro-mixing efficiency and shorten the mixing time has become an important research direction in microfluidic technology. Currently, the research on micro-mixers mainly focuses on improving the mixing efficiency by optimizing the structure design, introducing external driving forces (such as electric fields, magnetic fields, thermal fields, etc.), and adopting different mixing mechanisms (such as vortex flow, shear flow, etc.). However, most existing micro-mixers still have significant limitations when dealing with high-viscosity fluids or complex fluids, and many designs are difficult to balance cost, operability, and stability in practical applications. Therefore, there is an urgent need for a new type of micro-mixer structure or method to overcome the above deficiencies, improve the mixing effect, and meet a wider range of application requirements. Based on the above problems, the present invention proposes a three-dimensional spiral spherical structure passive micro-mixer and its preparation method, which has good mixing performance and is simple and fast to prepare Summary of the Invention

[0003] To solve the problem of low mixing efficiency of the micro-mixer, the present invention provides a three-dimensional spiral spherical structure passive micro-mixer and a manufacturing method thereof

[0004] The present invention adopts the following technical solutions

[0005] A three-dimensional spiral spherical structure passive micro-mixer and a manufacturing method thereof, characterized in that: the micro-mixer includes two inlets, one outlet, two inlet channels, two mixing channels, and one spherical container

[0006] Among them, the size of the inlet channel is 0.7×0.7×2.3 mm; the screw diameter of the mixing channel is 1.7 mm, the pitch is 1 mm, and the size is 0.7×0.7×2.51 mm; the diameter of the spherical container is 0.8 mm

[0007] A manufacturing method of a three-dimensional spiral spherical structure passive micro-mixer

[0008] Step 1: Print out the channel mold and the casting mold using a 3D printer. The materials of the channel mold and the casting mold are high-impact polystyrene resin (HIPS) respectively.

[0009] Step 2: Lay a layer of PDMS with a thickness of about 3 mm on the bottom of the casting mold, remove air bubbles from it, and perform heat drying and curing treatment.

[0010] Step 3: Place the channel mold into the casting mold with the solidified PDMS, pour PDMS again into the channel mold inside the casting mold, remove air bubbles from it, and perform heat drying and curing treatment.

[0011] Step 4: Take out the solidified PDMS with the channel mold from the casting mold, and use a punch to punch holes at the top of the inlet channel and the outlet channel. The diameter of the holes is 4 mm.

[0012] Step 5: Inject a certain amount of limonene solution into the punched PDMS block with the inlet and outlet at the middle position using a micro-needle syringe to accelerate dissolution, and place it fully immersed in the limonene solution for 10 hours to form a three-dimensional spiral spherical passive micromixer.

[0013] Preferably, each air bubble removal treatment is divided into two steps:

[0014] Step 1: In an ultrasonic cleaner, the frequency is 50 Hz and the cleaning duration is 15 min.

[0015] Step 2: Perform vacuum air bubble removal treatment for 40 min.

[0016] Preferably, the size of the casting mold is 5×5×3 mm. Description of the Drawings

[0017] Figure 1 is the structure of the micromixer.

[0018] Figure 2 is the channel mold.

[0019] Figure 3 is the size of the channel mold.

[0020] Figure 4 is the size of the side of the channel mold.

[0021] Figure 5 is the influence of the fluid injection flow rate on the mixing efficiency of the micromixer.

[0021] 101 is the inlet, 102 is the inlet, 103 is the outlet, 104 is the inlet channel, 105 is the inlet channel, 106 is the mixing channel, 108 is the spherical container, 107 is the mixing channel, 109 is the injection hole, 201 is the casting mold. Specific implementation method

[0022] The following is an illustration thereof with specific examples.

[0023] 1. Directly print the casting mold using a high-precision 3D printer Figure 2 for the casting mold.

[0024] 2. Cast the channel mold using PDMS.

[0025] 3. Cast a layer of PDMS with a thickness of about 3 mm at the bottom of the casting mold for defoaming, heating, drying, and curing treatment.

[0026] 4. Place the channel mold into the casting mold with PDMS at the bottom, and then cast PDMS to submerge the channel mold by 3 mm for defoaming, heating, drying, and curing treatment.

[0027] 5. Take out the PDMS with the channel mold, and drill a blind hole with a diameter of 4 mm at the ends of the inlet channel and the outlet channel.

[0028] 6. Immerse the drilled PDMS block in the limonene solution for 10 h for sufficient soaking.

[0029] The wall thickness between the blocks of the prepared three-dimensional spiral spherical structure passive micro-mixer PDMS is appropriate, not easily broken, with good sealing performance. The inner wall surface of the micro-channel is flat and free of burrs. Due to the good elasticity of PDMS, the holes of the micro-needle syringe are in a closed state and there will be no liquid leakage.

Claims

1. A three-dimensional spiral spherical structured edgeless micro-mixer and a method for making the same, characterized in that: The micro mixer includes an inlet 101 , an inlet 102 , an outlet 103 , an inlet channel 104 , an inlet channel 105 , a mixing channel 106 , a spherical container 108 , a mixing channel 107 , and an injection hole 109 .

2. A three-dimensional helical spherical passive micromixer and a method for making the same, characterized in that The manufacturing process and method thereof, and the manufacturing process and process parameters thereof are as follows: (1) The channel mold 201 and the casting mold are printed out by a 3D printer, wherein the materials of the channel mold 201 and the casting mold are high impact polystyrene resin (HIPS) and PLA, respectively. (2) A layer of PDMS with a thickness of about 3 mm was spread on the bottom of the casting mold, and then placed in an ultrasonic cleaning machine with a frequency set to 50 Hz and a cleaning time of 15 min. The mold was vacuumed and defoamed for 40 min, and then heated at 80°C for 30 min for drying. (3) Place the channel mold into the casting mold with solidified PDMS, cast the channel mold 201 in the casting mold again with PDMS, and then place it in an ultrasonic cleaner with a frequency set to 50 Hz for 15 minutes. Vacuum and defoam for 40 minutes, and heat at 80°C for 30 minutes to dry. (4) The solidified PDMS with the channel mold was removed from the casting mold, and holes were punched at the top of the inlet channel and the outlet channel using a puncher with a diameter of 4 mm. (5) A limonene solution was injected into the middle of the perforated PDMS block with an inlet and an outlet using a microneedle syringe to accelerate the dissolution of the middle part, and the block was placed in the limonene solution and fully immersed for 10 hours to form a three-dimensional spiral spherical passive micromixer.

3. The three-dimensional helical spherical passive micromixer and the method for making the same according to claim 1, characterized in that: The dimensions of the mixing channel are 0.7×0.7 mm, the pitch is 1 mm, the screw diameter is 1.6 mm, and the dimensions of the inlet channel and the outlet channel are 0.7×0.7×2 mm.

4. The three-dimensional helical spherical passive micromixer and the method for making the same according to claim 1, characterized in that: The diameter of the spherical mixing chamber is 0.8 mm and the cross-section of the spiral structure has the dimensions of a 0.7×0.7 square.

5. The three-dimensional helical spherical passive micromixer and the method for making the same according to claim 1, characterized in that: After injection with the microneedle syringe, the liquid will not flow out of the injection site due to the elasticity of PDMS.

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