CN108654490B - A chaotic flow-based micro-hybrid chip - Google Patents

Abstract

The invention relates to a micro-mixing chip based on chaotic flow, comprising a cover sheet and a bottom sheet bonded together, the cover sheet includes a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a plurality of new reverse U Type "curved and folded" channel and chip outlet channel, the bottom sheet includes T-shaped premixed channel and multiple new U-shaped "curved and folded" channels, the T-shaped premixed channel is connected with the first chip liquid inlet and outlet, respectively. The liquid inlet of the second chip is connected, the lower end of the "T" shape is a pre-mixing channel, the pre-mixing channel is connected with the micro-mixing unit, multiple groups of micro-mixing units are arranged and connected together, and the last group of micro-mixing units is connected with the chip outlet. The fluid port is connected. The invention imitates the "horseshoe transformation" process, designs a micron-scale chip structure, and performs operations such as "extrusion stretching", "bending and folding" on the fluid, inducing the moving fluid under laminar flow conditions to generate chaotic flow, thereby promoting the improvement of mixing efficiency. promote.

Description

A chaotic flow-based micro-hybrid chip

technical field

The invention belongs to the field of Micro-electro Mechanical Systems (MEMS), and relates to a chip for micro total analysis systems (μTAS) and a manufacturing method thereof.

Background technique

In addition to the injection pressure, the passive micro-mixer does not require other external excitation, and is more suitable for integration on the micro-total analysis system chip, together with other functional modules to achieve rapid detection of trace samples. However, on a μTAS chip with a structural feature size of 0.1 μm to 1 mm, the fluid generally moves under laminar flow conditions with low Reynolds number (Re), so special microstructures are required to operate the fluid to improve the mixing efficiency. the goal of. T-type and Y-type mixers are passive mixers with the simplest structure. They mainly use intermolecular diffusion motion to achieve mixing, and their mixing efficiency and mixing distance are difficult to meet the needs of μTAS chips. Adding obstacles in the microstructure can effectively improve the mixing efficiency, but the obstacles will greatly reduce the injection pressure, which will affect the work of the functional modules in the latter stage of the mixer. The split-confluence mixer designed according to Fick's law divides the fluid into multiple thin layers and then rejoins them. Although the ideal mixing efficiency can be obtained after repeated repetitions, the long mixing distance makes it still unsuitable for integration in μTAS. on the chip.

The microfluid under chaotic motion not only maintains the basic characteristics of laminar flow such as low flow velocity and small pressure drop, but also has a diffusion characteristic closer to the turbulent state, so the mixing efficiency is significantly improved. The Staggeredherringbone mixer (SHM) designed by Stroock et al. utilizes the staggered structure at the bottom of the microchannel to induce chaotic flow under low Reynolds number conditions. Song et al. optimized the design of SHM and replaced the three-dimensional structure with a two-dimensional structure, which further improved the mixing efficiency while reducing the difficulty of preparation. However, the optimized SHM still needs 15 cycles (the mixing distance is 27 mm) to achieve satisfactory mixing effect. Ottino et al. pointed out that according to the mathematical model of "Baker Map", "squeezing and stretching" and "cutting and stacking" operations on the fluid can successfully induce chaotic flow after repeated repetitions. Philippe et al. used the finite element method to analyze the mechanism of chaotic flow in the process of "baker's transformation", and verified the feasibility of the model for the design of micro-mixers. Takao et al. successfully prepared a micro-mixer according to the "baker's transformation". After 10 operations of "squeeze-stretch" and "cut-and-stack", a satisfactory mixing effect could be achieved within a distance of 10.4 mm. The semi-parallel "baker" micro-mixer designed by Peter et al. can perform multiple "cut-and-stack" operations on the fluid at the same time, so that the mixing efficiency increases exponentially. But 'cut-and-stack' operations on fluids require complex microstructures, making it difficult to integrate a 'baker' micromixer on the limited-volume μTAS chip.

The "Horseshoe Transformation" proposed by Smale is also a mathematical model that can induce chaotic flow inside a continuous system. In the transformation process, the "bend and fold" operation replaces the "cut and stack" operation. If it is applied to a micromixer The design can greatly reduce the difficulty of preparation and integration.

SUMMARY OF THE INVENTION

Purpose of invention:

The invention is based on MEMS technology and based on the mathematical model of "horseshoe transformation", and proposes a chaotic flow-based micro-mixing chip and a preparation scheme for a micro-full analysis system chip. Following the "horseshoe transformation" process, the micron-scale chip structure is designed, and the fluid is "extruded and stretched", "bent and folded" and other operations to induce chaotic flow in the moving fluid under laminar flow conditions, thereby promoting the improvement of mixing efficiency.

Technical solutions:

A chaotic flow-based micro-mixing chip, comprising a cover sheet and a bottom sheet bonded together, characterized in that: the cover sheet includes a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a plurality of new reverse U-shaped "bend and fold" channel and chip outlet channel, the bottom sheet includes T-shaped pre-mix channel and multiple new U-shaped "bend and fold" channels, the T-shaped pre-mix channel is like "T" shape, The left and right ends of the "T" type are the first liquid inlet channel and the second liquid inlet channel respectively, which are respectively connected with the liquid inlet port of the first chip and the liquid inlet port of the second chip. Mixed channel, the premixed channel communicates with one end of the new U-shaped "bend and folded" channel closest to the T-shaped premixed channel, and the two ends of the new U-shaped "bent and folded" channel are matched with the new U-shaped "bent and folded" channel. Both ends of the reverse U-shaped "bend and fold" channel are connected, and one end of the new reverse U-shaped "bend and fold" channel is connected with the new reverse U-shaped "bend and fold" channel of the next group of micro-mixing units. The U-shaped "bend and fold" channel is matched with the new reverse U-shaped "bend and fold" channel to form a group of micro-hybrid units, and multiple groups of micro-hybrid units are connected as described above. The "bend and fold" channel communicates with the chip liquid outlet.

The new U-shaped "bending and folded" channel is similar to a "U" shape. The two ends of the "U" shape are a liquid inlet and a liquid outlet respectively. The side of the liquid inlet close to the liquid outlet is provided with a first connecting channel. , the first connection channel is not communicated with the liquid outlet.

The new reverse U-shaped "bending and folded" channel is similar to the reverse "U" shape, the two ends of the reverse "U" shape are the reverse liquid inlet and the reverse liquid outlet respectively, the reverse liquid inlet and the new U-shaped " The first connection channel of the "bend and fold" channel is connected, and the reverse liquid outlet is provided with a second connection channel on the side away from the reverse liquid inlet, and the new reverse U-shaped "bend and fold" channel is connected with the new The liquid outlet of the U-shaped "bending and folding" channel is connected; a third connecting channel is provided on the other side of the reverse liquid outlet of the original reverse U-shaped "bending and folding" channel, and the new reverse U-shaped "bending and folding" channel The third connection channel is communicated with the reverse liquid inlet of the next micro-mixing unit.

The T-type premixed channel:

The length of the first liquid inlet channel is a, the height is a, and the width is 5a;

The length of the second liquid inlet channel is a, the height is a, and the width is 5a;

The length of the premixed channel is 5a, the height is 2.5a, and the width is a;

The new U-shaped "bend and fold" channel:

The length is 10a, the width is 10a, the height is 2.5a, and the cross section is a square with a side length of 2.5a; the length of the first connection channel is 2.5a, the height is 2.5a, and the width is 2.5a;

The new reverse U-shaped "bend and fold" channel:

The length is 10a, the width is 10a, the height is 2.5a, and the cross section is a square with a side length of 2.5a; the length of the second connection channel is 2.5a, the height is 2.5a, and the width is 2.5a; the length of the third connection channel is 2.5a, the height is 2.5a, and the width is 2.5a;

The above "length" is in the same direction, "height" is in the same direction, "width" is in the same direction, and a is any positive number.

A preparation method based on chaotic flow micro-mixing chip as described: it is characterized in that, the steps are as follows:

1) Use an engraving machine or 3D printer to make the first chip inlet, the second chip inlet, the chip outlet, the T-shaped premix channel, the new U-shaped "bend and fold" channel on the polymer base material , New reverse U-shaped "bending and folding" channel, chip outlet channel;

2) The substrate with the microstructure is sealed by a bonding method such as an organic solvent miscible immersion bonding method or an organic solvent fumigation bonding method.

Advantages and Effects:

The invention designs the micron-level mixing chip structure according to the mathematical model of "horseshoe transformation", performs operations such as "extrusion stretching", "bending and folding" on the fluid, successfully induces chaotic flow under laminar flow conditions, and realizes uniform mixing of the liquid. The chaotic micro-hybrid chip based on "horseshoe transformation" can improve its integration and portability without increasing the size of the micro-full analysis system chip and the difficulty of processing and assembly. Lay the foundation for the promotion and application of precision testing and other fields.

Description of drawings

Fig. 1 is a schematic diagram of "horseshoe transformation";

2 is a perspective view of a T-type premixed channel structure;

3 is a top view of a T-type premixed channel structure;

4 is a side view of a T-type premixed channel structure;

Figure 5 is a perspective view of the original U-shaped "bend and fold" channel structure;

Figure 6 is a perspective view of a new U-shaped "bend and fold" channel structure with a connecting channel;

Figure 7 is a top view of a new U-shaped "bend and fold" channel structure with connecting channels;

Figure 8 is a perspective view of the original reverse U-shaped "bend and fold" channel structure;

Figure 9 is a top view of the original reverse U-shaped "bend and fold" channel structure;

Figure 10 is a side view of the original reverse U-shaped "bend and fold" channel structure;

Figure 11 is a perspective view of a new reverse U-shaped "bend and fold" channel structure with connecting channels;

Figure 12 is a top view of a new reverse U-shaped "bend and fold" channel structure with connecting channels;

Figure 13 is a perspective assembly view of the new U-shaped "bend and fold" channel and the new reverse U-shaped "bend and fold" channel on one side of the premix channel;

Figure 14 is a top assembly view of the new U-shaped "bend and fold" channel and the new reverse U-shaped "bend and fold" channel;

Figure 15 is the front assembly view of the new U-shaped "bend and fold" channel and the new reverse U-shaped "bend and fold" channel;

Figure 16 is a side view assembly view of the new U-shaped "bend and fold" channel and the new reverse U-shaped "bend and fold" channel;

Figure 17 is a perspective view of the structure of the micro-mixer;

Figure 18 is a top view of the structure of the micro-mixer;

Figure 19 is a side view of the structure of the micro-mixer;

20 is a perspective view of a micro-mixer chip;

Figure 21 is a bottom view of a cover slip of a micromixer chip;

Figure 22 is a cross-sectional view of the microchannel on the micromixer chip before and after assembly;

Fig. 23 is the visual test effect diagram of the micro-mixer chip;

Figure 24 is a graph of solution pH testing using a micromixer chip.

Description of reference numerals: 1. T-shaped premix channel, 101. First liquid inlet channel, 102. Second liquid inlet channel, 103. Premix channel, 2-1. Original U-shaped "bend and fold" Channel, 2-2. New U-shaped "bend and fold" channel, 201. Liquid inlet, 202. Liquid outlet, 203. First connecting channel, 3-1. Original reverse U-shaped "bend and fold" channel Channel, 3-2. New reverse U-shaped "bend and fold" channel, 301. Reverse liquid inlet, 302. Reverse liquid outlet, 303. Second connection channel, 304. Third connection channel, 4. Micro Mixer, 401. Micro-mixing unit, 5. Liquid inlet of first chip, 6. Liquid inlet of second chip, 7. Liquid outlet of chip, 8. Cover sheet, 9. Negative film, 10. Micro-mixing chip, 11 . Chip outlet channel.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings:

According to the schematic diagram of the "horseshoe transformation" in Fig. 1, firstly, in the horizontal direction (but not limited to), the "liquid" (the dotted square in Fig. 1(a)) in the system U (the dotted box in Fig. 1(a)) The diagonal line in the box) "squeeze and stretch"; after "squeeze and stretch", part of the "liquid" overflows the system U (as shown in Figure 1(b)); "Return to the inside of the system U again (as shown in Figure 1(c)); in the vertical direction (but not limited to, the "liquid" inside the system U can be performed in a different direction from the previous "squeeze and stretch" direction). "Squeeze and stretch" and "bend and fold" operations, obtain the inverse transformation of "horseshoe transformation" (as shown in Figure 1(d)); inside the system U, take the intersection of "horseshoe transformation" and its inverse transformation, so that The "liquid" that has undergone the "horseshoe transformation" and its inverse transformation is reunited (as shown in Figure 1(e)); the above transformation process is symbolically correlated (as shown in Figure 1(a)-(f)), both using The characters represent the "liquid" before and after the transformation, so that mathematical derivation can be done to prove the existence of the chaotic flow after the transformation.

As shown in Fig. 2, Fig. 3 and Fig. 4 for the T-shaped premixing channel 1, the preferred length and height of the first liquid inlet channel 101 and the second liquid inlet channel 102 are a, and the width is 5a (but not limited to , greater than 2a). The premixing channel 103 is located between the first liquid inlet channel 101 and the second liquid inlet channel 102, and meets the two liquids to be mixed. The preferred width of the premixing channel 103 is a, and the length is 5a (but not It is limited to be larger than 2a), and the height is 2.5a (but not limited to, larger than 2a).

As shown in Figure 5, the original U-shaped "bending and folding" channel 2-1 has a square section with a side length of 2.5a, and communicates with other components through the liquid inlet 201 and the liquid outlet 202 at both ends of the "U" shape. As shown in Figures 6 and 7, the improved new U-shaped "bend and fold" channel 2-2 is added to the side of the liquid inlet 201 of the original U-shaped "bend and fold" channel 2-1 close to the liquid outlet 202 The first connection channel 203, the new U-shaped "bend and fold" channel 2-2 communicates with the reverse liquid inlet 301 of the new reverse U-shaped "bend and fold" channel 3-2 through the first connection channel 203.

As shown in Figure 8, Figure 9 and Figure 10, the original reverse U-shaped "bending and folding" channel 3-1 has a cross-section of a square with a side length of 2.5a, and the direction of reverse "bending and folding" of the liquid is the same as that of the original U Type "bend and fold" channel 2-1 opposite. The original reverse U-shaped "bend and fold" channel 3-1 communicates with other components through the reverse liquid inlet 301 and the reverse liquid outlet 302 at both ends of the reverse "U" shape.

As shown in Figures 11 and 12, the new reverse U-shaped "bend and fold" channel 3-2 is improved, and the reverse liquid outlet 302 of the original reverse U-shaped "bend and fold" channel 3-1 is far from the reverse liquid inlet 301. A second connection channel 303 is added on one side, and the new reverse U-shaped "bend and fold" channel 3-2 communicates with the liquid outlet 202 of the new U-shaped "bend and fold" channel 2-2 through the second connection channel 303; A third connection channel 304 is added on the other side of the reverse liquid outlet 302 of the original reverse U-shaped "bend and fold" channel 3-1, and the new reverse U-shaped "bend and fold" channel 3-2 passes through the third connection channel 304 It communicates with the next micro-mixing unit 401 .

13, 14, 15 and 16, the micro-hybrid unit 401 is obtained by superimposing the new U-shaped "bend and fold" channel 2-2 and the new reverse U-shaped "bend and fold" channel 3-2 owned. In the micro-mixing unit 401, the liquids that have been "bent and folded" in different directions are reunited to complete a "horseshoe transformation".

The micro-mixer 4 shown in FIG. 17 , FIG. 18 and FIG. 19 is composed of a T-shaped pre-mixing channel 1 and four micro-mixing units 401 with the same structure.

The micro-hybrid chip 10 shown in Figures 20 and 21 is made of a first chip liquid inlet 5, a second chip liquid inlet 6, a chip liquid outlet 7, and a new reverse U-shaped "bend and fold" channel. 3-2 is bonded to the cover sheet 8 of the microstructures of the chip outlet channel 11, and the bottom sheet 9 made of the microstructures of the T-shaped premix channel 1 and the new U-shaped "bend and folded" channel 2-2. to make. After bonding, the new reverse U-shaped "bend and fold" channel 3-2 and the new U-shaped "bend and fold" channel 2-2 constitute the micro-hybrid unit 401 .

Figure 22 is a cross-sectional view of the microchannel on the micromixer chip before and after assembly. It can be seen from the microchannel structure diagram before and after bonding assembly that the bonding process has little effect on the microstructure , the microchannel structure did not change significantly before and after bonding.

Fig. 23 The visual test effect diagram of the micro-mixer chip. It can be seen from Fig. 23A that when two tracers of different colors pass through the first micro-mixing unit 401, the interfaces of the two tracers are distinct; from Fig. 23B It can be seen from Figure 23C that after passing through the second micro-mixing unit 401, the interfaces of the two tracers have begun to blur; It can be seen from Figure 23D that after passing through the fourth micro-mixing unit 401, the tracer interface almost disappears, and the concentration of the liquid tends to be the same, which proves that the micro-channel designed based on the "horseshoe transformation" model The mixer can achieve the ideal mixing effect.

Figure 24 is a graph of solution pH testing using a micromixer chip.

The direction A ₁ -A ₂ in the drawing is the flow direction of the liquid as a whole.

The design principle of the present invention is as follows: According to the "horseshoe transformation" process shown in Figure 1, an intuitive relationship is established between letters and graphics through symbolic association, and the liquid to be mixed is represented as U after symbolic association. Using symbolic dynamics, it can be proved that after the "horseshoe transformation", the process of generating chaotic flow is as follows:

The "liquid" placed horizontally in the initial state can be represented by the symbols H ₀ and H ₁ after being associated with the symbols by the formula (1):

H ₀ ={(x,y)∈U|0≤x≤1,0≤y≤1/μ}

The "liquids" H ₀ and H ₁ are subjected to the "extrusion and stretching" operation, so that the "liquids" H ₀ and H ₁ shrink by λ in the horizontal direction (x-axis) and extend μ in the vertical direction (y-axis). After the operation, the "liquid" obtained can be represented by the Jacobian in formula (2):

Perform a "bending and folding" operation on the "liquids" H ₀ and H ₁ after "squeezing and stretching", so that the overflowing "liquid" is plugged back into the mixing unit U. The "liquid" obtained after the operation is represented as V ₀ and V ₁ after symbol association, and can be expressed as the mappings f(H ₀ ) and f(H ₁ ) as shown in formula (3):

V ₀ =f(H ₀ )={(x,y)∈U|0≤x≤λ,0≤y≤1}

V ₁ =f(H ₁ )={(x,y)∈U|1-λ≤x≤1,0≤y≤1} (3)

The "liquid" collection in the system U can be expressed as:

V _i =f(H _i )∩U(i=0,1) (4)

The inverse transforms of the "horseshoe change" can be constructed using the same method: H ₁ =f ^-1 (V ₀ ) and H ₂ =f ^-1 (V ₁ ). After inverse transformation, the "liquid" set in the system U can be expressed as:

H _i =f ^-1 (V _i )∩U(i=0,1) (5)

Then the intersection of the "horseshoe transformation" f(H _i ) and its inverse transformation f ^-1 (V _i ) can be expressed by equation (6):

Λ ₁ =f ^-1 (U)∩U∩f ¹ (U)=[(H ₀ ,V ₀ ),(H ₀ ,V ₁ ),(H ₁ ,V ₀ ),(H ₁ ,V ₁ ) ] (6)

As i → ∞, the "liquid" inside the system U will shrink to points, but will remain inside it all the time. From this, an iterative sequence Λ of i times can be constructed as shown in equation (7):

To sum up, the "horseshoe transformation" process can be equivalent to a symbolic dynamic system (f, Λ) built on the invariant set Λ. If it can be proved that (f, Λ) is chaotic, the "liquid" after "horseshoe transformation" is also chaotic. Lyapunov exponent (Lyapunovexponent) is the main basis for judging the chaotic nature of the system, and its positive and negative values indicate whether the system is chaotic. The two Lyapunov exponents (li _i ) of (f,Λ) can be calculated by equation (8).

l ₁ =ln|λ|; l ₂ =ln|μ| (8)

It can be seen that if the "liquid" in the system U is guaranteed to squeeze the amplitude λ<1/2 in the horizontal direction and stretch the amplitude μ>2 in the vertical direction during the "horseshoe transformation" process, then |μ|>2 , ln|μ|>0, the system is chaotic after horseshoe transformation. Therefore, in the structural design process of the micro-hybrid chip, it is determined that the length and height of the first liquid inlet channel 101 and the second liquid inlet channel 102 of the T-shaped premixing channel are a, and the width is 5a. When they meet, the width of the channel becomes a, the length becomes 5a, and the height becomes 2.5a, so as to satisfy the condition of "horseshoe transformation" to induce chaotic flow.

Preparation method of chaotic flow micromixer based on horseshoe transformation:

1) Use an engraving machine or 3D printer to make the first chip liquid inlet 5, the second chip liquid inlet 6, the chip liquid outlet 7, the T-shaped premix channel 1, the new U-shaped "bend" on the polymer base material "Folding" channel 2-2, new reverse U-shaped "bending and folding" channel 3-2, chip outlet channel 11;

2) The substrate with the microstructure is sealed by a bonding method such as an organic solvent miscible immersion bonding method or an organic solvent fumigation bonding method.

Example:

When a=200μm, according to the T-shaped pre-mixing channel, micro-mixing unit and micro-mixer structure shown in Fig. 2 to Fig. 19 , an ultra-precision engraving machine is used on the polymethyl methacrylate polymer base material. microstructure.

1) Prepare 110 ml of a miscible solution of absolute ethanol and chloroform according to the volume ratio V _chloroform :V _ethanol =1:10. Wet the two substrates with the microstructures in the above-mentioned miscible solution, fix them with a quartz glass fixture under a microscope, and put the fixed chips into a petri dish containing the miscible solution. Immediately put the petri dish into a drying oven, set the temperature at 40 °C, and bond for 10 min. The cross-sections of the microchannels on the micromixer chip before and after bonding assembly are shown in Figure 22.

2) Fluorescein Isothiocyanate (FITC) and Rhodamine B with a concentration of 1 mol/L were respectively prepared as tracers. Using the syringe pump as the driving force, the liquid mixing in the micro-mixing chip was observed with a fluorescence microscope, and the CCD screenshot processing was completed with ImageJ software, and the visual test photo shown in Figure 23 was obtained. It can be seen from FIG. 23A that when two tracers of different colors pass through the first micro-mixing unit 401, the interfaces of the two tracers are distinct; as can be seen from FIG. 23B, when the two tracers pass through the second After the mixing unit 401, the interface of the two tracers has begun to blur; it can be seen from Figure 23C that after the third micro-mixing unit 401, the interface of the two tracers is not easy to distinguish; from Figure 23D It can be seen that after passing through the fourth micro-mixing unit 401, the tracer interface almost disappears, and the concentration of the liquid tends to be the same, which proves that the micro-mixer designed based on the "horseshoe transformation" model can achieve an ideal mixing effect.

3) In order to test the actual mixing effect of the micro-mixer chip, buffer solutions with different pH values were prepared: potassium hydrogen phthalate (0.05mol/L, pH=4.01), mixed phosphate (0.025mol/L, pH=6.86) ), borax (0.01mol/L, pH=9.18) as test reagents. The specific steps of solution pH value test are as follows:

1. Take an equal volume (10ml) of the above-mentioned buffer solution, and after using a vortex stirrer to make it evenly mixed in pairs, the obtained control solution composition and pH value are shown in Table 1;

2. Using the dual-channel syringe pump as the driving force (set the flow rate to 2×10 ^-3 m/s, at this time Re=1), pass buffers with different pH values into the two inlets of the micromixer, and use the acidity meter Measure the pH value change at the outlet;

3. In order to ensure the consistency and accuracy of the results, the measurement was started after 1 minute of buffering and repeated three times. The obtained Reynolds number (Re) and the pH value of the mixed solution are shown in Figure 24.

The pH values of the three buffer solutions in Figure 24 fluctuated above the calibrated control value with the change of Re. When Re<0.5, the pH value at the outlet of the mixer gradually moved away from the control value with the increase of Re, indicating that the mixing The effect is decreasing; when Re ≥ 1, with the increase of Re, the pH value at the outlet of the mixer gradually approaches the control value, indicating that the mixing effect is improving. It can be seen that when the flow rate of the liquid in the mixer is low, diffusion and mass transfer play a leading role. At this time, the contact time of the two liquids decreases due to the increase of the flow rate, which in turn leads to a decrease in the mixing effect; with the increase of the flow rate, the chaotic flow The mass will play a leading role in the mixing process, and the chaotic flow will be enhanced by the increase of the flow velocity, which will improve the mixing effect.

1) Table 1 Control solution composition and pH value

Claims (3)

1. a micro-mixing chip based on chaotic flow, comprising a cover sheet and a negative sheet bonded together, it is characterized in that: the cover sheet comprises the first chip liquid inlet, the second chip liquid inlet, the chip liquid outlet, a plurality of New reverse U-shaped "bend and fold" channel and chip outlet channel, backsheet includes T-shaped premix channel and multiple new U-shaped "bend and fold" channels, the T-shaped pre-mix channel resembles a "T" Type, the left and right ends of the "T" type are the first liquid inlet channel and the second liquid inlet channel respectively, which are respectively connected with the liquid inlet of the first chip and the liquid inlet of the second chip. The lower end of the "T" type For the premix channel, the premix channel communicates with one end of the new U-shaped "bend and fold" channel closest to the T-shaped pre-mix channel, and the two ends of the new U-shaped "bend and fold" channel mate with it The two ends of the new reverse U-shaped "bend and fold" channel are connected, and one end of the new reverse U-shaped "bend and fold" channel is connected with the new reverse U-shaped "bend and fold" channel of the next group of micro-hybrid units. , the new U-shaped "bend and fold" channel and the new reverse U-shaped "bend and fold" channel matched with it form a group of micro-mixing units, multiple groups of micro-mixing units are connected as above, and the new reverse of the last group of micro-mixing units The U-shaped "bend and fold" channel communicates with the chip liquid outlet; The new U-shaped "bending and folded" channel is similar to a "U" shape. The two ends of the "U" shape are a liquid inlet and a liquid outlet respectively. The side of the liquid inlet close to the liquid outlet is provided with a first connecting channel. , the first connection channel is not communicated with the liquid outlet; The new reverse U-shaped "bending and folded" channel is similar to the reverse "U" shape, the two ends of the reverse "U" shape are the reverse liquid inlet and the reverse liquid outlet respectively, the reverse liquid inlet and the new U-shaped " The first connection channel of the "bend and fold" channel is connected, and the reverse liquid outlet is provided with a second connection channel on the side away from the reverse liquid inlet, and the new reverse U-shaped "bend and fold" channel is connected with the new The liquid outlet of the U-shaped "bend and fold" channel is connected; there is a third connection channel on the other side of the reverse liquid outlet of the new reverse U-shaped "bend and fold" channel, and the new reverse U-shaped "bend and fold" channel The channel communicates with the reverse liquid inlet of the next micro-mixing unit through the third connecting channel. 2. micro-mixing chip based on chaotic flow according to claim 1, is characterized in that: The T-type premixed channel: The length of the first liquid inlet channel is a, the height is a, and the width is 5a; The length of the second liquid inlet channel is a, the height is a, and the width is 5a; The length of the premixed channel is 5a, the height is 2.5a, and the width is a; The new U-shaped "bend and fold" channel: The length is 10a, the width is 10a, the height is 2.5a, and the cross section is a square with a side length of 2.5a; the length of the first connection channel is 2.5a, the height is 2.5a, and the width is 2.5a; The new reverse U-shaped "bend and fold" channel: The length is 10a, the width is 10a, the height is 2.5a, and the cross section is a square with a side length of 2.5a; the length of the second connection channel is 2.5a, the height is 2.5a, and the width is 2.5a; the length of the third connection channel is 2.5a, the height is 2.5a, and the width is 2.5a; The above "length" is in the same direction, "height" is in the same direction, "width" is in the same direction, and a is any positive number. 3. a preparation method based on chaotic flow micro-mixing chip as claimed in claim 1: it is characterized in that, step is as follows: 1) Use an engraving machine or 3D printer to make the first chip inlet, second chip inlet, chip outlet, T-shaped pre-mix channel, new U-shaped "bend and fold" channel on the polymer base material , New reverse U-shaped "bending and folding" channel, chip outlet channel; 2) The substrate with the microstructure is sealed by the organic solvent miscible immersion bonding method or the organic solvent fumigation bonding method.

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