A microreactor with controllable reaction process and preparation method thereof

Abstract

The present invention discloses a microreactor with controllable reaction process, including a fluid channel layer and a sealing layer, wherein a reaction channel, a confluence area and at least two feed channels are provided on the surface of the fluid channel layer, and the confluence area is provided at the intersection of the end of at least two feed channels and the beginning of the reaction channel; the sealing layer is covered and bonded to the fluid channel layer, and the sealing layer is provided with sealed inlets corresponding to the beginnings of the feed channels and sealed outlets corresponding to the ends of the reaction channels; the fluid channel layer and the sealing layer are made of flexible materials, and the cross section of the reaction channel changes when the microreactor is bent to affect the reaction process. The present invention also discloses a preparation method thereof. The channel cross section of the present invention can change with the macroscopic deformation of the microreactor, and the reaction process can be controlled in real time, thereby improving the controllability of the reaction; and it can adapt to the mixed reaction requirements of reactants with different flow rates and different viscosities.

Description

Technical Field

[0001] The invention belongs to the technical field of microreactors, and in particular relates to a microreactor with controllable reaction process and a preparation method thereof. Background Art

[0002] Microreactor technology has been widely used in many fields such as biological analysis, medical diagnosis, and chemical synthesis. With microstructure units as the core, chemical reactions are carried out in micron or submicron confined spaces. By reducing the dispersion scale of the system and strengthening mixing and transfer, it has many advantages such as efficient mixing ability, good mass and heat transfer characteristics, and highly controllable reaction process.

[0003] Microreactors can be divided into two types: static and dynamic. Static microreactors are the most widely used. They do not require external energy input. They mainly use the geometric structure of the reactor to increase the contact area of ​​the fluid, promote uniform mixing of the fluid, and fully react. They are mainly represented by obstacle type and flow channel structure type. Dynamic microreactors use external energy fields to promote fluid disturbance, destroy laminar flow, and promote chaotic convection. They are mainly represented by pressure drive and sound field drive.

[0004] A patent proposes "a micro-reaction channel structure and a microreactor based thereon", in which a certain number of spike structures are arranged on the inner wall or in the middle of the microchannel. These spikes are like petals in a flower, with roots gathered together and leaf tips spread out circumferentially. These spikes gathered at the roots constitute a microstructure, which is combined with piezoelectric ceramics as an active energy module to generate high-frequency vibration turbulence. This solves the shortcomings of existing microreactors such as long reaction distance and poor operability.

[0005] A patent proposes "a combined baffle microreactor", which consists of microreaction chambers arranged in an array on the opposite surfaces of an upper microreactor substrate and a lower microreactor substrate, microchannels that connect the microreaction chambers in sequence, and liquid inlet channels and liquid outlet channels; the microreaction chambers are elliptical, and a number of baffles for fluid folding are arranged in the direction of fluid flow; the outer diameter of the microchannel has a wave knot structure that can form fluid turbulence, so that the fluid can be repeatedly folded and collided, effectively improving the mixing effect of the fluid.

[0006] Although some existing microreactors have a certain degree of enhanced mixing effect, these microreactors generally have the following defects: 1. Poor controllability, usually only by adjusting the flow rate to control the reaction; 2. Fixed structure, unable to adapt to the mixing reaction requirements of reactants with different flow rates and different viscosities. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a microreactor with controllable reaction process and a preparation method thereof.

[0008] In order to achieve the above purpose, the technical solution of the present invention is:

[0009] A microreactor with a controllable reaction process comprises a fluid channel layer and a sealing layer. A reaction channel, a merging area and at least two feed channels are provided on the surface of the fluid channel layer. The merging area is provided at the intersection of the ends of at least two feed channels and the beginning of the reaction channel. The sealing layer is covered and bonded to the fluid channel layer. The sealing layer is provided with sealing inlets corresponding to the beginnings of the feed channels and sealing outlets corresponding to the ends of the reaction channels. The fluid channel layer and the sealing layer are made of flexible materials. When the microreactor is bent, the cross section of the reaction channel changes to affect the reaction process.

[0010] When external force is applied to bend the microreactor, the deformation brings the walls of the reaction channel closer to each other, reducing the width and cross-section of the reaction channel, thereby achieving control over the reaction.

[0011] Optionally, the fluid channel layer is further provided with a channel inlet at the starting end of each of the feed channels, and the channel inlet is matched and connected with the corresponding sealing inlet; the fluid channel layer is further provided with a reaction channel outlet at the end of the reaction channel, and the reaction channel outlet is matched and connected with the sealing outlet.

[0012] Optionally, the reaction channel extends in a zigzag manner along a first direction of the fluid channel layer, and a channel width of the reaction channel in the first direction changes when the microreactor is bent.

[0013] Optionally, the reaction channel is formed by alternately connecting longitudinal segments parallel to the first direction and transverse segments perpendicular to the first direction to perform the zigzag extension.

[0014] Optionally, the fluid channel layer and the sealing layer are made of PDMS thin film material, wherein the thickness of the fluid channel layer is 1-3 mm, and the depths of the plurality of feed channels, reaction channels and confluence areas are 200-900 μm.

[0015] Optionally, the reaction channel has a width of 3-20 μm when not under force, and a width variation range of 50-80% when bent.

[0016] The fluid channel layer and the sealing layer are made of the same batch of PDMS thin film materials, and the depths of the feed channel, the reaction channel and the confluence area are equal.

[0017] A method for preparing the above-mentioned microreactor with controllable reaction process comprises:

[0018] Step 1): Mixing PDMS material and curing agent to prepare a PDMS solution;

[0019] Step 2): pouring the PDMS solution onto the substrate, removing bubbles in the PDMS solution, and then heating and curing to obtain a PDMS film;

[0020] Step 3): peeling the PDMS film obtained in step 2) from the substrate, using ultraviolet laser to process the fluid channel, confluence area, reaction channel and inlet and outlet, and then cutting the film to obtain the fluid channel layer and the sealing layer;

[0021] Step 4): Bonding the fluid channel layer to the sealing layer, so that the feed channel, the reaction channel and the confluence area are enclosed with the sealing layer to form a channel cavity.

[0022] Optionally, in step 1), the PDMS material and the curing agent are mixed in a ratio ranging from 10:1 to 25:1; in step 2), the heating curing is performed at 50-75° C. for 6-8 hours.

[0023] Optionally, the laser power range of the ultraviolet laser processing used in step 3) is 5.8-8.8kw.

[0024] Optionally, the fluid channel layer and the sealing layer in step 4) are placed in a bonding machine, treated with oxygen plasma for 45-60 seconds, and aligned and bonded.

[0025] The width of the feed channel and the reaction channel is in the range of 3-20 μm, the diameter of the confluence area is in the range of 0.5-1.5 mm, the inlet and outlet apertures are in the range of 0.8-1.5 mm, and the channel depth is in the range of 200-900 μm. The inlet and outlet refer to the channel inlet and the sealing inlet, the channel outlet and the sealing outlet.

[0026] The beneficial effects of the present invention are:

[0027] 1. Compared with the existing microreactor, the adjustable flow channel cross section is increased. The present invention makes the reaction process further controllable on the basis of only being able to adjust the input flow rate;

[0028] 2. Compared with the existing microreactor with fixed channel structure, the channel structure of the present invention is controllable, can adapt to the mixed reaction requirements of different flow rates and reactants, and is not easy to be blocked;

[0029] 3. Compared with the existing microreactor processing method, the present invention uses ultraviolet laser processing, does not require molds and photolithography, greatly simplifies the process, and greatly reduces the processing difficulty of the microreactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is an exploded schematic diagram of a microreactor with controllable reaction process according to an embodiment of the present invention;

[0031] Figure 2is a schematic top view of a fluid channel layer according to an embodiment of the present invention;

[0032] Figure 3 is a schematic top view of a sealing layer according to an embodiment of the present invention;

[0033] Figure 4 is a schematic top view of a fluid channel layer in a bent state according to an embodiment of the present invention;

[0034] Figure 5 is a front schematic diagram of a fluid channel layer in a bent state according to an embodiment of the present invention;

[0035] Figure 6 is a top view of a reaction channel region according to an embodiment of the present invention;

[0036] Figure 7 is a top view of a reaction channel region after bending according to an embodiment of the present invention;

[0037] Figure 8 The present invention is a flowchart of a method for preparing a microreactor with controllable reaction process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. The various drawings of the present invention are only for illustration to make it easier to understand the present invention, and the specific proportions can be adjusted according to design requirements. The upper and lower relationships of the relative elements and the definitions of the front / back in the figures described in the text should be understood by those skilled in the art to refer to the relative positions of the components, so they can all be flipped to present the same components, which should all fall within the scope disclosed in this specification.

[0039] In this paper, the start and end are defined according to the flow direction of the fluid in the flow channel, that is, the fluid flows from the start to the end.

[0040] Reference Figures 1 to 3 A microreactor with controllable reaction process in the embodiment includes a fluid channel layer 100 and a sealing layer 200. The fluid channel layer 100 is provided with a first feed channel 111, a second feed channel 131, a reaction channel 121 and a confluence area 140. The confluence area 140 is arranged at the intersection of the end of the first feed channel 111, the end of the second feed channel 131 and the beginning of the reaction channel 121. The fluid channel layer 100 is also provided with a first feed channel inlet 110, a second feed channel inlet 130 and a reaction channel outlet 120. The first feed channel inlet 110 is connected to the beginning of the first feed channel 111, the second feed channel inlet 130 is connected to the beginning of the second feed channel 131, and the reaction channel outlet 120 is connected to the end of the reaction channel 121.

[0041] Reference Figure 1 Combination Figure 3 The sealing layer 200 is provided with a first sealing inlet 210, a second sealing inlet 230 and a sealing outlet 220, which are respectively located corresponding to the first feed channel inlet 110, the second feed channel inlet 130 and the reaction channel outlet 120. The sealing layer 200 is covered on the fluid channel layer 100, and the fluid channel layer 100 and the sealing layer 200 are bonded, so that the first feed channel 111, the second feed channel 131, the reaction channel 121 and the confluence area 140 are sealed and enclosed with the bottom surface of the sealing layer 200 to form a channel cavity.

[0042] The fluid channel layer 100 and the sealing layer 200 are formed of a bendable flexible material. The reaction channel 121 area is affected by the overall bending deformation of the microreactor, and the two side walls gradually approach each other, and the width and cross section of the reaction channel 121 are reduced, which affects the reaction process and effect. Figure 2 and Figures 4 to 7 , the reaction channel 121 extends in a zigzag manner along a first direction of the fluid channel layer 100, and the first feed channel 111 and the second feed channel 131 extend in a direction perpendicular to the first direction. When the microreactor is bent in a direction perpendicular to the first direction, the channel width of the reaction channel 121 in the first direction changes when the microreactor is bent. The first direction mentioned here refers to any direction on the surface of the fluid channel layer. Specifically, the reaction channel 121 is zigzagly extended by alternating longitudinal segments parallel to the first direction and transverse segments perpendicular to the first direction. The cross-sections of the longitudinal segments and the transverse segments change alternately, which lengthens the total length of the channel and is conducive to mixing reactions. Reference Figure 5 When bending in a direction perpendicular to the first direction, the deformation causes the walls of the reaction channel to approach each other, reducing the width and cross-section of the reaction channel, and the width of the channel in the longitudinal section becomes smaller, thereby achieving control over the reaction.

[0043] The width of the reaction channel is 3-20 μm when it is not subjected to force, and the width changes by 50-80% when it is bent.

[0044] The fluid channel layer 100 and the sealing layer 200 are made of the same batch of PDMS thin film materials. The first feed channel 111, the second feed channel 131, the reaction channel 121 and the confluence area 140 have the same depth. The width of the reaction channel 121 is determined according to the channel width range of the microreactor bending angle that can be adjusted.

[0045] refer to Figure 8 The method for preparing the above-mentioned microreactor with controllable reaction process comprises:

[0046] Step 1: Weigh 6 g of PDMS and 0.6 g of curing agent in a ratio of 10:1, and stir and mix thoroughly to prepare a PDMS solution; an example of the curing agent is SYLGARD 184, and other conventional curing agents may also be used.

[0047] Step 2: Pour the PDMS solution onto the silicon wafer, place it in a vacuum drying oven at -0.1 MPa for 0.5 h to remove bubbles, and place it in an oven at 55 ° C for 6 h to obtain a 1.5 mm thick PDMS film;

[0048] Step 3: Use ultraviolet laser processing with a laser power of 7Kw to process the fluid channel, the confluence area 140, the inlet and outlet, cut and remove the fluid channel layer 100 and the sealing layer 200, wherein the thickness of the fluid channel layer 100 is 1.5mm and the channel depth is 345μm; place the fluid channel layer 100 and the sealing layer 200 in an ultrasonic cleaning machine for cleaning for 3-5min, and dry them in an oven for 3-5min;

[0049] Step 4: Place the processed fluid channel layer 100 and the sealing layer 200 in a bonding machine, perform oxygen plasma treatment for 45 seconds, and align and bond them.

[0050] During manufacturing, the width range of the first feed channel 111, the second feed channel 131, and the reaction channel 121 is 3-20μm, the diameter range of the confluence area 140 is 0.5-1.5mm, the inlet and outlet (first sealed inlet 210, second sealed inlet 230, sealed outlet 220, first feed channel inlet 110, second feed channel inlet 130 and reaction channel outlet 120) aperture range is 0.8-1.5mm, and the channel depth range is 200-900μm.

[0051] The invention is applicable to, but not limited to, fluid dynamics control in microreactors, including flow control and flow resistance regulation, opening and closing of flow channels, and application occasions including: preparation of nanoparticles, synthesis of fine chemicals, etc.

[0052] In one embodiment, sulfur composite nanoparticles can be synthesized using a microreactor with controllable reaction process described in the present invention. Driven by a syringe pump, a mixture containing HCl, PVP, and deionized water is injected into the first feed channel 111, and a mixture containing sodium thiosulfate and deionized water is injected into the second feed channel 131, and the two are injected at different flow rates. A reaction occurs, and the resulting solution is collected in a centrifuge cup, centrifuged in a high-speed centrifuge, and after pouring out the supernatant, vacuum drying is performed to obtain S@PVP nanoparticles. By adjusting the different bending angles of the reactor, changing the width of the microchannel, adjusting the mixing and diffusion degree of the reactants, and reducing the mixing path required for complete mixing, the controllable preparation of S@PVP nanoparticles with a particle size of 248 to 785 nm can be achieved, which can be used as the negative electrode material of lithium-sulfur batteries.

[0053] The above embodiments are only used to further illustrate a microreactor with controllable reaction process and a preparation method thereof of the present invention, but the present invention is not limited to the embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the technical solution of the present invention.

Claims

1. A microreactor with controllable reaction process, characterized in that: The invention comprises a fluid channel layer and a sealing layer, wherein a reaction channel, a confluence area and at least two feed channels are provided on the surface of the fluid channel layer, wherein the confluence area is provided at the intersection of the ends of the at least two feed channels and the beginning of the reaction channel; the sealing layer is covered and bonded to the fluid channel layer, wherein the sealing layer is provided with sealing inlets corresponding to the beginnings of the feed channels and sealing outlets corresponding to the ends of the reaction channels; the material of the fluid channel layer and the sealing layer is PDMS film material, wherein the thickness of the fluid channel layer is 1-3 mm; the reaction channel is alternately connected by longitudinal sections parallel to a first direction and transverse sections perpendicular to the first direction so as to extend in a zigzag manner along the first direction, and when the microreactor is bent, the width of the reaction channel in the first direction changes, so that the cross section of the channel changes to affect the reaction process.

2. The microreactor with controllable reaction process according to claim 1, characterized in that: The fluid channel layer is also provided with a channel inlet at the beginning of each feed channel, and the channel inlet is matched and connected with the corresponding sealing inlet; the fluid channel layer is also provided with a reaction channel outlet at the end of the reaction channel, and the reaction channel outlet is matched and connected with the sealing outlet.

3. The microreactor with controllable reaction process according to claim 1, characterized in that: The depths of the feed channels, reaction channels and confluence areas are 200-900 μm.

4. The microreactor with controllable reaction process according to claim 1, characterized in that: The reaction channel has a width of 3-20 μm when not under force, and a width variation range of 50-80% when bent.

5. A method for preparing a microreactor with controllable reaction process according to any one of claims 1 to 4, characterized in that: include: Step 1): Mix the PDMS material and the curing agent to prepare a PDMS solution; Step 2): Pour the PDMS solution onto the substrate, remove the bubbles in the PDMS solution, and then heat and cure to obtain a PDMS film; Step 3): The PDMS film obtained in step 2) is peeled off from the substrate, and the fluid channel, the confluence area, the reaction channel and the inlet and outlet are processed using an ultraviolet laser, and then the film is cut to obtain a fluid channel layer and a sealing layer; Step 4): Bond the fluid channel layer to the sealing layer so that the feed channel, the reaction channel and the confluence area are enclosed with the sealing layer to form a channel cavity.

6. The preparation method according to claim 5, characterized in that: In step 1), the mixing ratio of the PDMS material and the curing agent is in the range of 10:1 to 25:1; in step 2), the heat curing is performed at 50-75° C. for 6-8 hours.

7. The preparation method according to claim 5, characterized in that: The laser power range of the ultraviolet laser processing used in step 3) is 5.8-8.8kw.

8. The preparation method according to claim 5, characterized in that: The fluid channel layer and the sealing layer in step 4) are placed in a bonding machine, treated with oxygen plasma for 45-60 seconds, and aligned and bonded.

Images