M-type passive micro-mixer based on hemispherical obstacles and manufacturing method of M-type passive micro-mixer

Abstract

The invention provides an M-shaped passive micro-mixer based on a hemispherical barrier and a manufacturing method thereof. The micro-mixer mainly comprises an inlet, an outlet, the hemispherical barrier and an M-shaped mixing channel, the mixing performance of the micro-mixer is enhanced mainly according to the fact that microfluid is interfered by semispherical barriers in an M-shaped channel and then randomly and irregularly moves. The manufacturing method of the micro-mixer comprises the steps that a high-precision 3D printer is used for printing a channel mold, and the channel mold is made of HIPS; pLA is used for printing the square pouring mold; pDMS is poured into the HIPS mold in the PLA and dried for 30 minutes, so that the PDMS is fully cured; punching the PDMS block at an inlet and an outlet; and fully soaking the punched PDMS block in limonene until the HIPS is completely dissolved. According to the process, photoetching operation on the PDMS surface is avoided, the manufacturing process is greatly simplified, and tedious processing steps in a traditional method are avoided. In addition, overall treatment of the small particles can be efficiently completed in the mixing cavity. In general, the micro-mixer is very suitable for large-scale production and application by virtue of a simple manufacturing process and low production cost.

Description

Technical Field

[0001] The present invention relates to an M-type passive micro-mixer based on hemispherical obstacles and a manufacturing method thereof Background Art

[0002] In recent years, with the development of technology, the basic theory of fluid flow has been relatively perfect at the conventional scale. However, compared with the conventional-scale flow, the micro-scale flow exhibits unique characteristics. These characteristics are mainly reflected in the definition and range of flow characteristic parameters, the establishment of basic equations, the determination of boundary conditions, and the equation-solving methods. Microfluidic technology is widely used in the design and manufacture of various micro-functional devices, such as micro-mixers, micropumps, and microvalves, which are usually made of substrates such as silicon and glass. Micro-mixers have become a research hotspot because they can achieve fast and uniform mixing processes, and have important application values especially in the fields of chemistry, medicine, drug delivery, and nucleic acid detection. In miniaturized systems, the size of devices usually ranges from a few hundred micrometers to a few millimeters. As an important part of the microfluidic system, the ability to quickly mix two or more substances is crucial. Micro-mixers can be divided into two categories: active and passive, depending on whether an external driving force is required. Active mixers rely on external forces such as ultrasonic waves, magnetic forces, electric forces, or mechanical drives, while passive mixers improve the mixing efficiency through changes in structural design. Currently, most passive micro-mixers adopt a planar two-dimensional structure, but there are still great limitations in mixing fluids among many micro-mixers, with low mixing efficiency and complex preparation processes. Therefore, there is an urgent need for a micro-mixer with simple preparation and high mixing efficiency to overcome the above defects. Based on the above problems, the present invention proposes an M-type passive micro-mixer based on hemispherical obstacles and a manufacturing method thereof, with good mixing performance, simple and fast preparation

[0003] To solve the problem of low mixing efficiency of micro-mixers, the present invention provides an M-type passive micro-mixer based on hemispherical obstacles and a manufacturing method thereof

[0004] The present invention adopts the following technical solutions

[0005] An M-type passive micro-mixer based on hemispherical obstacles and a manufacturing method thereof, characterized in that: the micro-mixer includes two inlets, one outlet, two inlet channels, one M-type mixing channel, and four pairs of a total of eight hemispherical obstacles

[0006] Among them, the sizes of the two inlet channels are both 1×1×5 mm; the outer circular diameter of the M-type mixing channel is 6 mm; the inner circular diameter of the M-type mixing channel is 4 mm; the diameters of the eight hemispherical obstacles in the M-type mixing channel are all 0.8 mm

[0007] An M-type passive micro-mixer based on hemispherical obstacles and a manufacturing method thereof

[0008] Step 1: Use a high-precision 3D printer to print a channel mold made of high-impact polystyrene resin (HIPS) and a casting mold made of PLA.

[0009] Step 2: Pour a layer of PDMS about 1 mm thick at 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 flat in the exact middle of the PDMS casting mold with a solidified layer, and use PDMS to pour the channel mold in the casting mold until the PDMS is 1 mm higher than the mold, remove air bubbles from it, and perform heat drying and curing treatment.

[0011] Step 4: Take out the solidified PDMS block with the channel mold, and use a PDMS punch to punch holes with a diameter of 1.5 mm at the top of the inlet channel and the outlet channel.

[0012] Step 5: Inject a certain amount of limonene solution into the punched PDMS block with the inlet and outlet in the middle position using a micro-needle syringe to accelerate dissolution, and then place it inside the limonene solution and soak it fully for 12 hours to form an M-type passive micromixer with hemispherical obstacles.

[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 30 min.

[0015] Step 2: Perform vacuum air bubble removal treatment for 50 min.

[0016] Preferably, the size of the casting mold is 15×20×3 mm. Description of the Drawings

[0017] Figure 1 It is the structure of an M-type passive micromixer with hemispherical obstacles.

[0018] Figure 2 It is the channel mold.

[0019] Figure 3 The appearance of the M-type passive micromixer with hemispherical obstacles.

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

[0021] Figure 5 It is the obstacle at the semi-circular part of the M-type passive micromixer with hemispherical obstacles.

[0022] Figure 6 It is the obstacle at the corner of the M-type passive micromixer with hemispherical obstacles.

[0023] Figure 7 The influence of fluid injection flow rate on the mixing efficiency of the micromixer.

[0024] Among them, 101 is the inlet, 104 is the inlet, 110 is the outlet, 102 is the inlet channel, 103 is the inlet channel, 105 is the M-shaped mixing channel, 106 is the hemispherical obstacle, 107 is the hemispherical obstacle, 108 is the hemispherical obstacle, 109 is the hemispherical obstacle, 111 is the injection hole, 201 is the casting mold, 301 is the inlet, 302 is the inlet, 303 is the outlet, 304 is the injection hole. Specific implementation method

[0025] The following is an illustration with specific examples.

[0026] 1. Directly print the casting mold using a high-precision 3D printer. Figure 2 of the casting mold.

[0027] 2. Cast the channel mold using PDMS.

[0028] 3. Cast a layer of PDMS with a thickness of about 1 mm at the bottom of the casting mold, and then perform defoaming, heating and drying for curing.

[0029] 4. Place the channel mold into the casting mold with PDMS at the bottom, and then cast PDMS to submerge the channel mold by 1 mm, and perform defoaming, heating and drying for curing.

[0030] 5. Take out the PDMS with the channel mold, drill a blind hole with a diameter of 1.5 mm at the ends of the two inlet channels and the outlet channel, and inject a certain amount of limonene solution in the middle of the micromixer with a micro-needle syringe.

[0031] 6. Immerse the PDMS block with drilled holes in the limonene solution for 12 h for sufficient soaking.

[0032] The wall thickness between the prepared PDMS blocks of the M-shaped passive micromixer with hemispherical obstacles is appropriate, not easy to break, with good sealing performance. The inner wall surface of the microchannel 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. An M-type passive micromixer based on hemispherical obstacles and a method for making the same, characterized in that: The micro mixer includes an inlet 101 , an inlet 104 , an outlet 110 , an inlet channel 102 , an inlet channel 103 , an M-type mixing channel 105 , a hemispherical obstacle 106 , a hemispherical obstacle 107 , a hemispherical obstacle 108 , a hemispherical obstacle 109 , and an injection hole 111 .

2. An M-type passive micromixer based on hemispherical obstacles 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 1 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 30 min. The mold was vacuumed and defoamed for 50 min, and then heated at 80°C for 60 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 30 minutes. Vacuum and defoam for 50 minutes, and heat at 80°C for 60 minutes to dry. (4) The solidified PDMS with the channel mold was removed from the casting mold, and a hole was punched at the top of the inlet channel and the outlet channel using a puncher with a diameter of 1.5 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 12 hours to form an M-type passive micromixer with a hemispherical barrier.

3. The M-type passive micro-mixer based on hemispherical obstacles and the method for making the same according to claim 1, characterized in that: The dimensions of the M-type mixing channel are a total length of 17 mm, the dimensions of the inlet channel and are 1×1×5 mm, and the dimensions of the outlet channel are 1×1×1 mm.

4. The M-type passive micro-mixer based on hemispherical obstacles and the method for making the same according to claim 1, characterized in that: The diameter of the spherical obstacle is 0.8 mm and it is close to the upper and lower sides of the channel. The outer side of the M-shaped channel is a semicircle with a diameter of 6 mm, and the inner side is a semicircle with a diameter of 4 mm.

5. The M-type passive micro-mixer based on hemispherical obstacles 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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