CN108654490B - Micro-mixing chip based on chaotic stream - Google Patents
Micro-mixing chip based on chaotic stream Download PDFInfo
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- CN108654490B CN108654490B CN201810547149.XA CN201810547149A CN108654490B CN 108654490 B CN108654490 B CN 108654490B CN 201810547149 A CN201810547149 A CN 201810547149A CN 108654490 B CN108654490 B CN 108654490B
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Abstract
The invention relates to a chaotic-flow-based micro-mixing chip, which comprises a cover plate and a bottom plate, wherein the cover plate and the bottom plate are bonded together, the cover plate comprises a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a plurality of reverse U-shaped bent and folded channels and a chip liquid outlet channel, the bottom plate comprises a T-shaped premixing channel and a plurality of U-shaped bent and folded channels, the T-shaped premixing channel is respectively communicated with the first chip liquid inlet and the second chip liquid inlet, the lower end of the T-shaped premixing channel is communicated with micro-mixing units, a plurality of groups of micro-mixing units are arranged and communicated together, and the last group of micro-mixing units are communicated with the chip liquid outlet. According to the invention, a micron-sized chip structure is designed by imitating a 'horseshoe transformation' process, the operations of 'extruding, stretching', 'bending, folding' and the like are carried out on fluid, the chaotic flow of the moving fluid under the laminar flow condition is induced to generate, and the improvement of the mixing efficiency is further promoted.
Description
Technical Field
The invention belongs to the field of Micro-electro Mechanical Systems (MEMS), and relates to a Micro total analysis Systems (mu TAS) chip and a manufacturing method thereof.
Background
Besides the sample introduction pressure, the passive micro mixer does not need other external excitation, is more suitable for being integrated on a chip of a micro total analysis system, and realizes the rapid detection of trace samples together with other functional modules. However, in the μ TAS chip with a characteristic feature size of 0.1 μm to 1mm, the fluid generally moves under a laminar condition with a low Reynolds number (Re), so that the fluid needs to be operated by a special microstructure to achieve the purpose of improving the mixing efficiency. The T-type and Y-type mixers are passive mixers with the simplest structure, mainly utilize intermolecular diffusion motion to realize mixing, and the mixing efficiency and the mixing distance of the T-type and Y-type mixers are difficult to meet the requirements of a mu TAS chip. The mixing efficiency can be effectively improved by adding the barrier in the microstructure, but the barrier greatly reduces the sample injection pressure, and the work of a function module at the rear stage of the mixer is influenced. The flow splitting and merging type mixer designed according to Fick law can obtain ideal mixing efficiency after being repeatedly divided into a plurality of thin layers and then is recombined, but the ideal mixing efficiency is still not suitable for being integrated on a mu TAS chip due to the overlong mixing distance.
The microfluid under chaotic motion not only keeps the basic laminar flow characteristics of low flow speed, small pressure drop and the like, but also has the diffusion characteristic closer to the turbulent flow state, so that the mixing efficiency is obviously improved. A Staggered Herringbone Mixer (SHM) designed by Stroock et al can induce chaotic flow under the condition of low Reynolds number by utilizing a Staggered structure at the bottom of a microchannel. Song and the like carry out optimization design on the SHM, and a three-dimensional structure is replaced by a two-dimensional structure, so that the preparation difficulty is reduced, and the mixing efficiency is further improved. However, the optimized SHM still requires 15 cycles (mixing distance of 27mm) to achieve satisfactory mixing. Ottino et al teach that chaotic flow can be successfully induced by multiple iterations of "squeeze-stretch" and "cut-stack" operations on fluids according to a "Baker's transform" (Baker Map) mathematical model. Philippe et al analyzed the mechanism of chaotic flow generation in the "baker's transformation" process using a finite element method, and verified the feasibility of the model for the design of a micromixer. Takao et al successfully prepared a micromixer according to the "baker's transform" and after 10 "extrusion-stretching" and "cutting-stacking" operations, a satisfactory mixing effect was achieved within a distance of 10.4 mm. The semi-parallel structure baker micro-mixer designed by Peter and the like can simultaneously perform 'cutting and stacking' operation on fluid for many times, so that the mixing efficiency is exponentially increased. But the "cut stack" operation on the fluid requires a complex microstructure and therefore the integration of a "baker" micromixer on a μ TAS chip of limited volume is very difficult.
The horse shoe Transformation (Horseshoe Transformation) proposed by Smale is also a mathematical model capable of inducing chaotic flow in a continuous system, and the bending and folding operation is used for replacing the cutting and stacking operation in the Transformation process, so that the preparation and integration difficulty can be greatly reduced if the horse shoe Transformation is applied to the design of a micro mixer.
Disclosure of Invention
The purpose of the invention is as follows:
the invention provides a chaotic flow-based micro-hybrid chip for a micro total analysis system chip and a preparation scheme thereof based on an MEMS (micro-electromechanical systems) process and according to a mathematical model of 'horseshoe transform'. A micron-scale chip structure is designed by imitating the process of 'horseshoe transformation', the operations of 'extrusion stretching', 'bending folding' and the like are carried out on fluid, the chaotic flow generated by the moving fluid under the laminar flow condition is induced, and the improvement of the mixing efficiency is promoted.
The technical scheme is as follows:
the chaotic flow based micro mixing chip comprises a cover plate and a bottom plate which are bonded together, and is characterized in that: the cover plate comprises a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a plurality of new reverse U-shaped bent and folded channels and a chip liquid outlet channel, the bottom plate comprises a T-shaped premixing channel and a plurality of new U-shaped bent and folded channels, the T-shaped premixing channel is similar to a T shape, the left end and the right end of the T shape are respectively provided with a first liquid inlet channel and a second liquid inlet channel which are respectively communicated with the first chip liquid inlet and the second chip liquid inlet, the lower end of the T shape is provided with the premixing channel, the premixing channel is communicated with one end of the new U-shaped bent and folded channel closest to the T-shaped premixing channel, the two ends of the new U-shaped bent and folded channel are communicated with the two ends of the new reverse U-shaped bent and folded channel matched with the new U-shaped bent and folded channel, one end of the new reverse U-shaped bent and folded channel is communicated with the new reverse U-shaped bent and folded channel of the next group of, the new U-shaped bent and folded channels and the matched new reverse U-shaped bent and folded channels form a group of micro-mixing units, the multiple groups of micro-mixing units are communicated in the above mode, and the new reverse U-shaped bent and folded channels of the last group of micro-mixing units are communicated with a chip liquid outlet.
The novel U-shaped bending and folding channel is similar to a U shape, a liquid inlet and a liquid outlet are respectively arranged at two ends of the U shape, a first connecting channel is arranged at one side of the liquid inlet close to the liquid outlet, and the first connecting channel is not communicated with the liquid outlet.
The novel reverse U-shaped bent and folded channel is similar to an inverted U-shaped channel, a reverse liquid inlet and a reverse liquid outlet are respectively arranged at two ends of the inverted U-shaped channel, the reverse liquid inlet is communicated with a first connecting channel of the novel U-shaped bent and folded channel matched with the reverse liquid inlet, a second connecting channel is arranged on one side, away from the reverse liquid inlet, of the reverse liquid outlet, and the novel reverse U-shaped bent and folded channel is communicated with a liquid outlet of the novel U-shaped bent and folded channel through the second connecting channel; and a third connecting channel is arranged on the other side of the reverse liquid outlet of the original reverse U-shaped bent and folded channel, and the new reverse U-shaped bent and folded channel is communicated with the reverse liquid inlet of the next micro-mixing unit through the third connecting channel.
The T-shaped premixing channel:
the length of the first liquid inlet channel is a, the height of the first liquid inlet channel is a, and the width of the first liquid inlet channel is 5 a;
the length of the second liquid inlet channel is a, the height of the second liquid inlet channel is a, and the width of the second liquid inlet channel is 5 a;
the length of the premixing channel is 5a, the height is 2.5a, and the width is a;
the new U-shaped "bent folded" channel:
the length is 10a, the width is 10a, the height is 2.5a, and the section is a square with the side length of 2.5 a; the length of the first connecting channel is 2.5a, the height is 2.5a, and the width is 2.5 a;
the new reverse U-shaped "bent folded" channel:
the length is 10a, the width is 10a, the height is 2.5a, and the section is a square with the side length of 2.5 a; the length of the second connecting channel is 2.5a, the height of the second connecting channel is 2.5a, and the width of the second connecting channel is 2.5 a; the length of the third connecting channel is 2.5a, the height of the third connecting channel is 2.5a, and the width of the third connecting channel is 2.5 a;
the length is the same direction, the height is the same direction, the width is the same direction, and a is any positive number.
A preparation method of the chaotic flow based micro-mixing chip comprises the following steps: the method is characterized by comprising the following steps:
1) manufacturing a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a T-shaped premixing channel, a new U-shaped bending and folding channel, a new reverse U-shaped bending and folding channel and a chip liquid outlet channel on a polymer substrate material by using an engraving machine or a 3D printer;
2) sealing the substrate with the microstructure by using a bonding method such as an organic solvent mixing and soaking bonding method or an organic solvent fumigating bonding method.
The advantages and effects are as follows:
the invention designs a micron-scale mixing chip structure according to a mathematical model of 'horse shoe transformation', carries out operations of 'extrusion stretching', 'bending folding' and the like on fluid, successfully induces chaotic flow under a laminar flow condition, and realizes uniform mixing of liquid. The chaos micro-hybrid chip based on 'horseshoe transformation' can improve the integration and portability degrees of the micro-total analysis system without increasing the chip volume of the micro-total analysis system and the processing and assembling difficulty, and lays a foundation for the popularization and application of the technology in the fields of wearable medical equipment, intelligent precision detection and the like.
Drawings
FIG. 1 is a schematic view of "horseshoe conversion";
FIG. 2 is a perspective view of a T-shaped premixing channel structure;
FIG. 3 is a top view of a T-shaped premixing channel structure;
FIG. 4 is a side view of a T-shaped premixing channel arrangement;
FIG. 5 is a perspective view of an original U-shaped "bent and folded" channel structure;
FIG. 6 is a perspective view of a new U-shaped "bent folded" channel structure with connecting channels;
FIG. 7 is a top view of the new U-shaped "bent folded" channel structure with connecting channels;
FIG. 8 is a perspective view of an original reverse U-shaped "bent and folded" channel structure;
FIG. 9 is a top view of an original inverted U-shaped "bent folded" channel structure;
FIG. 10 is a side view of an original inverted U-shaped "bent folded" channel structure;
FIG. 11 is a perspective view of a new inverted U-shaped "flex-fold" channel configuration with connecting channels;
FIG. 12 is a top view of a new inverted U-shaped "flex-fold" channel structure with connecting channels;
FIG. 13 is a perspective assembly view of the new U-shaped "flex-fold" channel and the new inverted U-shaped "flex-fold" channel on one side of the premixing channel;
FIG. 14 is a top assembly view of the new U-shaped "flex-fold" channel and the new inverted U-shaped "flex-fold" channel;
FIG. 15 is an elevational assembly view of the new U-shaped "flex-fold" channel and the new inverted U-shaped "flex-fold" channel;
FIG. 16 is a side assembly view of the new U-shaped "flex-fold" channel and the new inverted U-shaped "flex-fold" channel;
fig. 17 is a perspective view of a micro mixer structure;
FIG. 18 is a top view of a micro-mixer structure;
FIG. 19 is a side view of a micromixer configuration;
fig. 20 is a perspective view of a micro-mixer chip;
FIG. 21 is a bottom view of a cover sheet of a micro-mixer chip;
FIG. 22 is a cross-sectional view of micro-channels on a micro-mixer chip before and after assembly;
fig. 23 is a diagram of the effect of a visual test of a micro mixer chip;
fig. 24 is a graph of solution pH testing using a micromixer chip.
Description of reference numerals: the liquid level sensor comprises a T-shaped premixing channel, 101, a first liquid inlet channel, 102, a second liquid inlet channel, 103, a premixing channel, 2-1, an original U-shaped bending and folding channel, 2-2, a new U-shaped bending and folding channel, 201, a liquid inlet, 202, a liquid outlet, 203, a first connecting channel, 3-1, an original reverse U-shaped bending and folding channel, 3-2, a new reverse U-shaped bending and folding channel, 301, a reverse liquid inlet, 302, a reverse liquid outlet, 303, a second connecting channel, 304, a third connecting channel, 4, a micromixer, 401, a micromixer unit, 5, a first chip liquid inlet, 6, a second chip liquid inlet, 7, a chip liquid outlet, 8, a cover plate, 9, 10, a micromixer chip, and 11, a chip liquid outlet channel.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
according to the schematic "horseshoe change" in fig. 1, the "liquid" (the oblique line in the dashed box in fig. 1 (a)) in the system U (the dashed box in fig. 1 (a)) is first "squeezed and stretched" in the horizontal direction (but not limited thereto); after "squeeze and stretch", part of the "liquid" overflows the system U (as shown in fig. 1 (b)); the overflowed "liquid" is returned to the inside of the system U again by "bending folding" (as shown in fig. 1 (c)); the "squeeze-stretch" and "bend-fold" operations are performed on the "liquid" inside the system U in the vertical direction (but not limited to, as opposed to the previous "squeeze-stretch" direction), resulting in the inverse of the "horseshoe transform" (as shown in fig. 1 (d)); taking the intersection of the 'horseshoe transformation' and the inverse transformation thereof inside the system U, and enabling the 'liquids' subjected to the 'horseshoe transformation' and the inverse transformation thereof to be recombined (as shown in fig. 1 (e)); the above transformation process is sign-correlated (as shown in fig. 1(a) - (f)), even though characters are used to represent "liquid" before and after transformation, so as to make mathematical derivation, and prove the existence of chaotic flow after transformation.
As shown in fig. 2, 3 and 4, the first liquid inlet channel 101 and the second liquid inlet channel 102 of the T-shaped premixing channel 1 preferably have a length and a height of a and a width of 5a (but not limited to, more than 2 a). The premixing channel 103 is located between the first liquid inlet channel 101 and the second liquid inlet channel 102, and meets two liquids to be mixed, and the premixing channel 103 preferably has a width a, a length 5a (but not limited to, greater than 2 a), and a height 2.5a (but not limited to, greater than 2 a).
As shown in FIG. 5, the original U-shaped channel 2-1 is a square channel with a side length of 2.5a, and is communicated with other components through a liquid inlet 201 and a liquid outlet 202 at two ends of the U-shaped channel. As shown in FIG. 6 and FIG. 7, a new U-shaped channel 2-2 is formed by modifying, wherein a first connecting channel 203 is added on one side of the liquid inlet 201 of the original U-shaped channel 2-1 close to the liquid outlet 202, and the new U-shaped channel 2-2 is communicated with a reverse liquid inlet 301 of a new reverse U-shaped channel 3-2 through the first connecting channel 203.
The original reverse U-shaped "flex-folded" channel 3-1, as shown in FIGS. 8, 9 and 10, is square with sides of 2.5a in cross-section, and the reverse "flex-folded" direction of the liquid is opposite to that of the original U-shaped "flex-folded" channel 2-1. The original reverse U-shaped bending folding channel 3-1 is communicated with other components through a reverse liquid inlet 301 and a reverse liquid outlet 302 at two ends of the reverse U-shaped bending folding channel.
As shown in fig. 11 and 12, a second connecting channel 303 is added to the reverse liquid outlet 302 of the original reverse U-shaped channel 3-1 away from the reverse liquid inlet 301, and the new reverse U-shaped channel 3-2 is communicated with the liquid outlet 202 of the new U-shaped channel 2-2 through the second connecting channel 303; a third connecting channel 304 is added on the other side of the reverse liquid outlet 302 of the original reverse U-shaped channel 3-1, and the new reverse U-shaped channel 3-2 is communicated with the next micro-mixing unit 401 through the third connecting channel 304.
The micro-hybrid unit 401 shown in fig. 13, 14, 15 and 16 is obtained by stacking a new U-shaped "meander-folded" channel 2-2 and a new inverted U-shaped "meander-folded" channel 3-2. In the micro-mixing unit 401, the liquids that have undergone the "bending folding" in different directions are recombined to complete a "horseshoe transformation".
The micromixer 4 shown in fig. 17, 18, and 19 is composed of a T-shaped premixing channel 1 and four micromixer units 401 having the same structure.
The micro-hybrid chip 10 shown in fig. 20 and 21 is formed by bonding a cover sheet 8 having microstructures such as a first chip inlet 5, a second chip inlet 6, a chip outlet 7, a new reverse U-shaped channel 3-2 and a chip outlet channel 11, and a base sheet 9 having microstructures such as a T-shaped pre-mixing channel 1 and a new U-shaped channel 2-2. The bonded new inverted U-shaped "flex-fold" channel 3-2 and new U-shaped "flex-fold" channel 2-2 form micro-hybrid unit 401.
Fig. 22 is a cross-sectional view of the micro-channels on the micro-mixer chip before and after assembly, and it can be seen from the micro-channel structure diagrams before and after bonding assembly that the bonding process has almost no influence on the microstructure, and the micro-channel structure before and after bonding has not changed significantly.
Fig. 23 is a graph of the visual test effect of the micro mixer chip, and it can be seen from fig. 23A that the interface of two tracers with different colors is clear after the two tracers pass through the first micro mixing unit 401; as can be seen in fig. 23B, the interface of the two tracers has begun to blur after passing through the second micro-mixing unit 401; as can be seen in fig. 23C, the interface of the two tracers is not readily discernable after passing through the third micro-mixing unit 401; as can be seen from fig. 23D, after passing through the fourth micro-mixing unit 401, the tracer interface almost disappears, and the concentrations of the liquids tend to be consistent, which proves that the micro-mixer designed based on the "horseshoe transform" model can achieve the ideal mixing effect.
Fig. 24 is a graph of solution pH testing using a micromixer chip.
In the attached drawing A1-A2The direction is the direction of flow of the liquid population.
The design principle of the invention is as follows: according to the "horseshoe transform" process shown in fig. 1, letters and figures are set up in an intuitive relationship by symbol association, and the liquid to be mixed is represented as U after symbol association. The sign dynamics can prove that the process of generating the chaotic stream after the 'horse shoe transformation' is as follows:
the symbol H can be used after symbol correlation of the horizontally placed 'liquid' in the initial state0、H1Can be represented by the formula (1):
H0＝{(x,y)∈U|0≤x≤1,0≤y≤1/μ}
for "liquid" H0、H1Performing extrusion-drawing operation to make liquid H0、H1Contract in the horizontal direction (x-axis) by λ and expand in the vertical direction (y-axis) by μ. The "liquid" obtained after the operation can be represented by the Jacobian in formula (2):
to the ' liquid ' H after the ' extrusion and stretching0、H1A "flex fold" operation is performed to cause the spilled "liquid" to pack back inside the mixing unit U. The 'liquid' obtained after operation is indicated as V after symbol correlation0、V1Can be expressed as a mapping f (H) as shown in equation (3)0) And f (H)1)：
V0＝f(H0)＝{(x,y)∈U|0≤x≤λ,0≤y≤1}
V1＝f(H1)＝{(x,y)∈U|1-λ≤x≤1,0≤y≤1} (3)
The "liquid" collection within the system U after the "squeeze-stretch" and "bend-fold" operations can be expressed as:
Vi＝f(Hi)∩U(i＝0,1) (4)
the inverse "horseshoe change" transformation can be constructed using the same method: h1＝f-1(V0) And H2＝f-1(V1). After the inverse transformation, the set of "liquids" within the system U can be represented as:
Hi＝f-1(Vi)∩U(i＝0,1) (5)
then "horse shoe transform" f (H)i) Inverse transformation of f-1(Vi) The intersection of (d) can be represented by equation (6):
Λ1＝f-1(U)∩U∩f1(U)＝[(H0,V0),(H0,V1),(H1,V0),(H1,V1)] (6)
when i → ∞ the "liquid" within the system U will contract to a point but will remain inside it. Therefore, an i-time iteration sequence Lambda shown in the formula (7) can be constructed:
to sum upThe "horseshoe transformation" process can be equivalent to a symbolic kinetic system (f, Λ) built on invariant set Λ. If (f, Λ) can be proved to have chaos, the liquid after the horseshoe transformation also has chaos. Lyapunov exponent (Lyapunov) is the main basis for judging the chaos of the system, and the positive and negative values indicate whether the system has chaos. Two Lyapunov indices (l) of (f, Λ)i) Can be calculated by equation (8).
l1＝ln|λ|；l2＝ln|μ| (8)
It can be seen that if the "liquid" in the system U is ensured 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", then with | μ | >2 and ln | μ | >0, the system has chaos after horseshoe transformation. Therefore, in the structural design process of the micro-hybrid chip, 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 determined to be a, the width is determined to be 5a, and when the two liquids meet, the width of the channel is changed to be a, the length of the channel is changed to be 5a, and the height of the channel is changed to be 2.5a, so that the condition that the chaotic flow is induced by the 'horseshoe transformation' is met.
The preparation method of the chaotic flow micromixer based on the horseshoe transformation comprises the following steps:
1) manufacturing a first chip liquid inlet 5, a second chip liquid inlet 6, a chip liquid outlet 7, a T-shaped premixing channel 1, a new U-shaped bent and folded channel 2-2, a new reverse U-shaped bent and folded channel 3-2 and a chip liquid outlet channel 11 on a polymer substrate material by using an engraving machine or a 3D printer;
2) sealing the substrate with the microstructure by using a bonding method such as an organic solvent mixing and soaking bonding method or an organic solvent fumigating bonding method.
Example (b):
when a is 200 μm, a microstructure is machined on the polymethylmethacrylate polymer base material using an ultra-precise engraving machine according to the T-type premixing channel, the micro-mixing unit and the micro-mixing mechanism shown in fig. 2 to 19.
1) In volume ratio VTrichloromethane:VEthanol1:10 preparing absolute ethyl alcohol and trichloro-methylAnd 110 ml of alkane miscible solution. And (3) wetting two substrates with microstructures in the miscible solution respectively, fixing the substrates by using a quartz glass fixture under a microscope, and putting the fixed substrates into a culture dish containing the miscible solution. The petri dish was immediately placed in a drying oven, set at 40 ℃, and bonded for 10 min. The cross-section of the micro-channels on the micro-mixer chip before and after bond assembly is shown in fig. 22.
2) Fluorescein Isothiocyanate (FITC) and rhodamine B (Rhodamine B) with the concentration of 1mol/L are respectively prepared to be used as tracers. The injection pump was used as power, the liquid mixing conditions in the micro-mixing chip were observed with a fluorescence microscope, and the CCD screenshot processing was completed with ImageJ software, resulting in the visual test photograph shown in fig. 23. As can be seen from fig. 23A, when two tracers of different colors pass through the first micro-mixing unit 401, the interface of the two tracers is clear; as can be seen in fig. 23B, the interface of the two tracers has begun to blur after passing through the second micro-mixing unit 401; as can be seen in fig. 23C, the interface of the two tracers is not readily discernable after passing through the third micro-mixing unit 401; as can be seen from fig. 23D, after passing through the fourth micro-mixing unit 401, the tracer interface almost disappears, and the concentrations of the liquids tend to be consistent, which proves that the micro-mixer designed based on the "horseshoe transform" model can achieve the ideal mixing effect.
3) In order to test the actual mixing effect of the micro-mixer chip, buffers 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) were used as test reagents. The solution pH value test comprises the following specific steps:
1. taking the buffer solution with the same volume (10ml), uniformly mixing every two buffer solutions by using a vortex stirrer to obtain a control solution, wherein the composition and the pH value of the control solution are shown in table 1;
2. using a double-channel injection pump as power (setting flow rate of 2X 10)-3m/s, at the moment, Re is 1), introducing buffers with different pH values into two liquid inlets of the micro mixer, and measuring the change condition of the pH value at an outlet by using an acidimeter;
3. to ensure the consistency and accuracy of the results, the measurement was started after 1 minute of buffer introduction and repeated 3 times, and the Reynolds number (Re) obtained as a function of the pH of the mixed solution is shown in FIG. 24.
The pH values of all three buffer solution combinations in fig. 24 fluctuate above the calibrated control as Re changes, and when Re <0.5, the pH value at the mixer outlet gradually moves away from the control as Re increases, indicating that the mixing effect is decreasing; when Re.gtoreq.1, the pH at the mixer outlet gradually approached the control with increasing Re, indicating that the mixing effect was improving. Therefore, when the flow rate of the liquid in the mixer is low, the diffusion mass transfer plays a leading role, and the contact time of the two liquids is reduced due to the increase of the flow rate, so that the mixing effect is reduced; with the increase of the flow velocity, the chaotic flow mass transfer plays a leading role in the mixing process, and at the moment, the chaotic flow is enhanced due to the increase of the flow velocity, so that the mixing effect is improved.
1) TABLE 1 control solution composition and pH
Claims (3)
1. The chaotic flow based micro mixing chip comprises a cover plate and a bottom plate which are bonded together, and is characterized in that: the cover plate comprises a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a plurality of new reverse U-shaped bent and folded channels and a chip liquid outlet channel, the bottom plate comprises a T-shaped premixing channel and a plurality of new U-shaped bent and folded channels, the T-shaped premixing channel is similar to a T shape, the left end and the right end of the T shape are respectively provided with a first liquid inlet channel and a second liquid inlet channel which are respectively communicated with the first chip liquid inlet and the second chip liquid inlet, the lower end of the T shape is provided with the premixing channel, the premixing channel is communicated with one end of the new U-shaped bent and folded channel closest to the T-shaped premixing channel, the two ends of the new U-shaped bent and folded channel are communicated with the two ends of the new reverse U-shaped bent and folded channel matched with the new U-shaped bent and folded channel, one end of the new reverse U-shaped bent and folded channel is communicated with the new reverse U-shaped bent and folded channel of the next group of, the new U-shaped bent and folded channel and the matched new reverse U-shaped bent and folded channel form a group of micro-mixing units, the plurality of groups of micro-mixing units are communicated in the above way, and the new reverse U-shaped bent and folded channel of the last group of micro-mixing units is communicated with a chip liquid outlet;
the novel U-shaped bending and folding channel is similar to a U shape, a liquid inlet and a liquid outlet are respectively arranged at two ends of the U shape, a first connecting channel is arranged at one side of the liquid inlet close to the liquid outlet, and the first connecting channel is not communicated with the liquid outlet;
the novel reverse U-shaped bent and folded channel is similar to an inverted U-shaped channel, a reverse liquid inlet and a reverse liquid outlet are respectively arranged at two ends of the inverted U-shaped channel, the reverse liquid inlet is communicated with a first connecting channel of the novel U-shaped bent and folded channel matched with the reverse liquid inlet, a second connecting channel is arranged on one side, away from the reverse liquid inlet, of the reverse liquid outlet, and the novel reverse U-shaped bent and folded channel is communicated with a liquid outlet of the novel U-shaped bent and folded channel through the second connecting channel; and a third connecting channel is arranged on the other side of the reverse liquid outlet of the new reverse U-shaped bent and folded channel, and the new reverse U-shaped bent and folded channel is communicated with the reverse liquid inlet of the next micro-mixing unit through the third connecting channel.
2. The chaotic-flow-based micro-hybrid chip according to claim 1, wherein:
the T-shaped premixing channel:
the length of the first liquid inlet channel is a, the height of the first liquid inlet channel is a, and the width of the first liquid inlet channel is 5 a;
the length of the second liquid inlet channel is a, the height of the second liquid inlet channel is a, and the width of the second liquid inlet channel is 5 a;
the length of the premixing channel is 5a, the height is 2.5a, and the width is a;
the new U-shaped "bent folded" channel:
the length is 10a, the width is 10a, the height is 2.5a, and the section is a square with the side length of 2.5 a; the length of the first connecting channel is 2.5a, the height is 2.5a, and the width is 2.5 a;
the new reverse U-shaped "bent folded" channel:
the length is 10a, the width is 10a, the height is 2.5a, and the section is a square with the side length of 2.5 a; the length of the second connecting channel is 2.5a, the height of the second connecting channel is 2.5a, and the width of the second connecting channel is 2.5 a; the length of the third connecting channel is 2.5a, the height of the third connecting channel is 2.5a, and the width of the third connecting channel is 2.5 a;
the length is the same direction, the height is the same direction, the width is the same direction, and a is any positive number.
3. A method for preparing the micro-hybrid chip based on chaotic streams according to claim 1: the method is characterized by comprising the following steps:
1) manufacturing a first chip liquid inlet, a second chip liquid inlet, a chip liquid outlet, a T-shaped premixing channel, a new U-shaped bending and folding channel, a new reverse U-shaped bending and folding channel and a chip liquid outlet channel on a polymer substrate material by using an engraving machine or a 3D printer;
2) sealing the substrate with the microstructure by using an organic solvent miscible soaking bonding method or an organic solvent fumigation bonding method.
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| WO2022229721A1 (en) * | 2021-04-29 | 2022-11-03 | Instituto Tecnológico y de Estudios Superiores de Monterrey | Method for printing microlayers and multilayered nanostructures ordered by chaotic flows |
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