A centrifugal microfluidic reactor and its application

Abstract

The present invention relates to the field of microfluidic reactors, and discloses a centrifugal microfluidic reactor and its application. The centrifugal microfluidic reactor comprises a cover plate, a reaction chip and a bottom plate stacked in sequence. The reaction chip is provided with a storage bin A, a storage bin B, an outlet channel A, an outlet channel B, a mixing channel and a mixing chamber; the storage bin A and the storage bin B are located in the center of the reaction chip and are distributed alternately; the mixing chamber is located at the edge of the reaction chip; the material inlet A / material inlet B, the storage bin A / storage bin B, the outlet channel A / outlet channel B, the mixing channel and the mixing chamber are connected in sequence. The present invention proposes a new centrifugal microfluidic reactor, which can be used to regulate the particle size, purity, morphology and other properties of microfluidic synthesized nanoparticles, and the synthesis efficiency is higher, which can provide a favorable basis for synthesizing nanoparticles with customized properties.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic reactors, in particular to a centrifugal microfluidic reactor and applications thereof. Background Art

[0002] Nanoparticles have attracted significant attention in scientific and technological research due to their unique properties and wide range of applications. Nickel oxide (Ni2O3) nanoparticles, in particular, have emerged as a promising material due to their excellent electrical, optical, and magnetic properties. However, conventional nickel oxide synthesis methods often encounter challenges in achieving precise control over the size, shape, and composition of nanoparticles, limiting their potential for advanced applications. To overcome these limitations, microfluidics has emerged as a new approach to synthesize Ni2O3 nanoparticles, offering improved control, reproducibility, and scalability.

[0003] In recent years, microfluidics, which involves the manipulation of fluids at the microscopic scale, has gained attention for its ability to precisely control reaction conditions and exhibit unique fluid behaviors. Microfluidic platforms offer numerous advantages for nanoparticle synthesis, including superior mixing efficiency, rapid heat transfer, and the ability to execute multiple steps in a controlled manner. These properties enable precise control of nucleation, growth, and assembly processes, facilitating the synthesis of Ni2O3 nanoparticles with tailored properties.

[0004] Several synthetic strategies have successfully achieved controlled production of nanoparticles in microfluidic systems. For example, Lian et al. (2020) effectively connected the microfluidics for manufacturing TiO2 nanoparticles through a surfactant-coated sol-gel strategy, enabling the uniform delivery of TiO2 nanoparticles to the outer surface of multi-walled carbon nanotubes (MWCNTs) and the ability to retain rhodamine B for wastewater treatment. However, this method has a low throughput and cannot be applied to stable scale-up and industrialization. At the same time, the above-mentioned synthetic process has limited control over aspects such as nanoparticle size and needs further optimization. Summary of the Invention

[0005] To address the above technical issues, the present invention provides a centrifugal microfluidic reactor and its application. This invention proposes a novel centrifugal microfluidic reactor that can be used to control properties such as particle size, purity, and morphology of microfluidic-synthesized nanoparticles. This centrifugal microfluidic reactor also offers improved synthesis efficiency, providing a foundation for synthesizing nanoparticles with customized properties.

[0006] The specific technical solutions of the present invention are:

[0007] In a first aspect, the present invention provides a centrifugal microfluidic reactor comprising a cover plate, a reaction chip, and a bottom plate stacked sequentially from top to bottom. In particular:

[0008] The cover plate is provided with at least one A material inlet and at least one B material inlet.

[0009] The reaction chip is provided with at least one A storage bin, at least one B storage bin, at least one A outlet channel, at least one B outlet channel, at least one mixing channel, and at least one mixing chamber; the A storage bin and the B storage bin are located in the center of the reaction chip and are distributed alternately; the mixing chamber is located at the edge of the reaction chip; the A material inlet / B material inlet, the A storage bin / B storage bin, the A outlet channel / B outlet channel, the mixing channel, and the mixing chamber are connected in sequence.

[0010] The working principle of the centrifugal microfluidic reactor of the present invention is as follows: the raw material liquid A and raw material liquid B for nanoparticle synthesis are respectively injected into the A storage bin and the B storage bin through the A material inlet and the B material inlet; the centrifugal microfluidic reactor is fixed on a centrifuge and centrifuged. Under the action of centrifugal force, the raw material liquid A and raw material liquid B are respectively transmitted through the A and B outlet channels and then converge at the mixing channel, and further fully mixed and reacted in the mixing chamber. In addition, the reactor rotates alternately clockwise and counterclockwise during centrifugation, making the liquid flow field in the mixing chamber more unstable, significantly increasing the phase exchange, and thus significantly improving the reaction efficiency. After the reaction is completed, the centrifugation is stopped, the product is collected in the mixing chamber, and the nanoparticles are obtained after post-processing.

[0011] Unlike existing microfluidic reactors, the microfluidic reactor of the present invention is of centrifugal design. Since the forward and reverse acceleration of the centrifuge can be adjusted in the range of 1-40rad / s2, the particle size / morphology of the nanoparticles can be finely controlled during the preparation process by controlling variables such as rotational acceleration, speed, and mixing time.

[0012] Furthermore, because nanoparticles are synthesized, conventional microfluidic reactors are limited by channel size and generally have low efficiency. However, the present invention utilizes a centrifugal microfluidic reactor, which leverages centrifugal force to effectively increase the reaction rate within the microchannel reactor, significantly boosting yield. By designing the reactor structure and controlling the centrifugal speed and reaction time, nanoparticles with a narrow particle size distribution can be obtained.

[0013] In order to make the microfluidic reactor more suitable for centrifugal treatment, the present invention optimizes the microfluidic reactor as follows:

[0014] (1) The storage bin is designed at the center of the reaction chip, and the mixing chamber, the main place for mixing and reaction, is designed at the edge of the reactor. This design facilitates the transfer of raw material liquid from the storage bin to the mixing chamber under the action of centrifugal force.

[0015] (2) Storage bins A and B are alternately distributed at the center of the reaction chip, allowing the same storage bin to feed multiple mixing chambers at the same time, reducing the volume and making the reactor structure more compact.

[0016] Preferably, the reaction chip is disc-shaped and is provided with multiple A storage bins, B storage bins, A outlet channels, B outlet channels, mixing channels and mixing chambers; and each A outlet channel, B outlet channel, mixing channel and mixing chamber constitutes a unit; and the multiple units are evenly and symmetrically distributed on the reaction chip.

[0017] In order to further make the microfluidic reactor suitable for centrifugal reaction, the present invention designs the reaction chip into a disc shape, and makes multiple units evenly and symmetrically distributed on the reaction chip, ensuring the consistency of feeding and reaction of each unit during the centrifugation process.

[0018] Preferably, in each of the units, outlet channel A and outlet channel B are symmetrically arranged, and the channel formed by outlet channel A, outlet channel B and mixing channel is Y-shaped; the connection point between the mixing channel and the mixing chamber is located on the center line of the mixing chamber.

[0019] Designing the A outlet channel, B outlet channel and mixing channel into a Y shape can also ensure the feeding stability of the raw material liquids A and B.

[0020] Preferably, the connecting end between the A outlet channel and the A storage bin, and the connecting end between the B outlet channel and the B storage bin are both curved flow channels; the connecting ends of the curved flow channel and the A storage bin and the B storage bin are respectively oriented toward the center of the reaction chip (that is, the arc at the connection with the storage bin is perpendicular); the A outlet channel and the B outlet channel form an angle of 85-95°.

[0021] The curved flow channel design allows for smooth material discharge during centrifugal processing, regardless of forward or reverse rotation. The 85-95° angle between outlet channels A and B is the optimal angle range determined by fluid dynamics simulation data. This facilitates rapid, uniform, and efficient mixing of the two materials without affecting flow rate.

[0022] Preferably, the width of the outlet channel A and the outlet channel B is 0.5-3 mm; the width of the mixing channel is 1-6 mm, and the width of the outlet channel A and the outlet channel B is smaller than the width of the mixing channel.

[0023] Preferably, the connection between the A storage bin and the A outlet channel, and the connection between the B storage bin and the B outlet channel are both provided with a trumpet-shaped fluid expansion groove with a decreasing flow path.

[0024] The design of the fluid expansion groove has a larger outflow surface, which can help the fluid flow more smoothly to the A and B outlet channels and the mixing channel under the action of centrifugal force.

[0025] Preferably, the mixing chamber is connected to the outlet of the mixing channel through an inlet convex cavity located at the top thereof. The mixing chamber is fan-shaped, and the inlet convex cavity is arc-shaped and located near the edge of the reaction chip.

[0026] The inlet convex cavity serves to connect with the mixing channel. The present invention designs the inlet convex cavity at the top of the edge of the mixing cavity, on the same level as the mixing channel. Therefore, under the action of centrifugal force, the feed liquid will first converge at the inlet convex cavity for further mixing and reaction. The advantage of the arc-shaped design is that it is conducive to the back and forth flow and collision of the feed liquid under the alternating clockwise and counterclockwise centrifugal rotation, thereby making the flow field here more unstable and significantly increasing the phase exchange (such as Figure 13 shown).

[0027] Preferably, at least one ventilation hole is provided on the top of each mixing chamber in the reaction chip and the cover plate.

[0028] During the research and development process, the inventor's team discovered that when the mixed raw liquid enters the mixing chamber, it repels the enclosed mixing chamber gas, adversely affecting the dynamics of the material under centrifugal action. To address this, the inventor designed a ventilation hole at the top of the mixing chamber to expel the gas. Furthermore, since atmospheric pressure remains balanced, only the internal and external air pressures need to be maintained consistent. Therefore, when the material enters the mixing chamber, only gas is expelled, without backflow.

[0029] Preferably, the ventilation hole is located in the mixing chamber close to the center of the reaction chip.

[0030] The ventilation holes are located near the center of the reaction chip because the mixing chamber is typically not fully loaded with liquid. Therefore, under centrifugal force, the liquid concentrates at the far edge of the mixing chamber, leaving a gap near the center. Placing the ventilation holes at this top position prevents liquid from being thrown out.

[0031] Preferably, the reaction chip is provided with a detachable bottom sealing plate at the bottom of the mixing chamber.

[0032] The detachable bottom sealing plate is convenient for collecting the products after the reaction.

[0033] In a second aspect, the present invention provides an application of the centrifugal microfluidic reactor in nanoparticle synthesis.

[0034] Preferably, the application includes: injecting raw material liquid A and raw material liquid B for nanoparticle synthesis into storage bin A and storage bin B through material inlet A and material inlet B, respectively; fixing the centrifugal microfluidic reactor on a centrifuge and performing a centrifugal reaction, rotating alternately clockwise and counterclockwise during the centrifugation; after the reaction is completed, stopping the centrifugation, collecting the product in the mixing chamber, and obtaining nanoparticles after washing, filtering, drying, and grinding.

[0035] Preferably, the nanoparticles do not contain nickel oxide nanoparticles.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention proposes a new centrifugal microfluidic reactor, which can be used to control the particle size, purity, morphology and other properties of microfluidic synthesized nanoparticles, and the synthesis efficiency is higher, which can provide a favorable basis for the synthesis of nanoparticles with customized properties.

[0038] (2) The present invention optimizes part of the structure of the centrifugal microfluidic reactor in a targeted manner based on the characteristics of the centrifugal microfluidic technology, making the reactor more suitable for centrifugal reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the overall appearance of a centrifugal microfluidic reactor of the present invention;

[0040] Figure 2 A side perspective view of a centrifugal microfluidic reactor of the present invention;

[0041] Figure 3 A top view of the cover plate of the centrifugal microfluidic reactor of the present invention;

[0042] Figure 4 A bottom view of the cover plate of the centrifugal microfluidic reactor of the present invention;

[0043] Figure 5 A top view of the reaction chip of the centrifugal microfluidic reactor of the present invention;

[0044] Figure 6 A perspective view of a reaction chip of a centrifugal microfluidic reactor of the present invention;

[0045] Figure 7 A bottom view of the reaction chip of the centrifugal microfluidic reactor of the present invention;

[0046] Figure 8 A schematic structural diagram of a bottom sealing plate of a centrifugal microfluidic reactor of the present invention;

[0047] Figure 9A top view of the bottom plate of the centrifugal microfluidic reactor of the present invention;

[0048] Figure 10 A bottom view of the bottom plate of the centrifugal microfluidic reactor of the present invention;

[0049] Figure 11 Schematic diagram of force distribution and direction on the rotating centrifuge chip;

[0050] Figure 12 Schematic diagram of the steady state of fluid flow in the channel;

[0051] Figure 13 The velocity vector distribution results of the channel after counterclockwise and clockwise centrifugation at 500 rpm;

[0052] Figure 14 This is the SEM image of the Ni2O3 nanoparticles synthesized in Example 2;

[0053] Figure 15 The X-ray diffraction (XRD) pattern of Ni2O3 nanoparticles synthesized in Example 2 of the present invention;

[0054] Figure 16 is the particle size distribution diagram of each group of nanoparticles;

[0055] Figure 17 Figure 2 shows the particle size distribution of each group of nanoparticles under different conditions: (a) different time and acceleration at 1000 rpm; (b) different time and acceleration at 500 rpm; (c) different speed and acceleration at 5 min; (d) different speed and acceleration at 10 min.

[0056] The figures are marked as: cover plate 1, reaction chip 2, bottom plate 3, material inlet A 11, material inlet B 12, fluid expansion groove 20, material storage bin A 21, material storage bin B 22, outlet channel A 23, outlet channel B 24, mixing channel 25, mixing chamber 26, inlet convex chamber 27, ventilation hole 28, bottom sealing plate 29. DETAILED DESCRIPTION

[0057] The present invention will be further described below with reference to the embodiments.

[0058] Overall embodiment

[0059] A centrifugal microfluidic reactor comprises a cover plate 1, a reaction chip 2 and a bottom plate 3 stacked in sequence from top to bottom. The cover plate is disc-shaped and is provided with at least one inlet 11 for material A and at least one inlet 12 for material B.

[0060] The reaction chip is disc-shaped and is provided with at least one A storage bin 21, at least one B storage bin 22, at least one A outlet channel 23, at least one B outlet channel 24, at least one mixing channel 25, and at least one mixing chamber 26. Specifically:

[0061] Storage bin A and storage bin B are located in the center of the reaction chip and are distributed alternately; the mixing chamber is fan-shaped and located at the edge of the reaction chip; the mixing chamber is connected to the outlet end of the mixing channel through an arc-shaped inlet convex cavity 27 located at the top of the reaction chip near the edge of the reaction chip. At least one ventilation hole 28 is provided at the top of each mixing chamber near the center of the reaction chip in the reaction chip and the cover plate. A removable bottom sealing plate 29 is provided at the bottom of each mixing chamber. A material inlet / B material inlet, storage bin A / storage bin B, outlet channel A / outlet channel B, mixing channel and mixing chamber are connected in sequence. In the case where there are multiple storage bins A, storage bins B, outlet channels A, outlet channels B, mixing channels and mixing chambers, the same storage bins A and B are connected to multiple outlet channels A and B, and each outlet channel A, outlet channel B, mixing channel and mixing chamber constitutes a unit, and multiple units are evenly and symmetrically distributed on the reaction chip. In each unit, outlet channel A and outlet channel B are symmetrically arranged, and the channel formed by outlet channel A, outlet channel B and mixing channel is Y-shaped (outlet channel A and outlet channel B are at an angle of 85-95°). Further preferably, the connection between the A storage bin and outlet channel A, and the connection between the B storage bin and outlet channel B are both provided with a fluid expansion groove 20 with a trumpet-shaped decreasing flow path. At the same time, the connection end between outlet channel A and storage bin A, and the connection end between outlet channel B and storage bin B are both curved flow channels; the connection ends of the curved flow channels and storage bin A and storage bin B are respectively facing the center of the reaction chip; the connection point between the mixing channel and the mixing chamber is located on the center line of the mixing chamber. The width of outlet channel A and outlet channel B is 0.5-3mm; the width of the mixing channel is 1-6mm, and the width of outlet channel A and outlet channel B is less than the width of the mixing channel. The bottom plate is disc-shaped and is detachably connected to the reaction chip.

[0062] Optionally, the cover plate, the reaction chip and the base plate are made of plastic such as acrylic, PEEK, PTFE, PFA, or metal such as 316L.

[0063] The centrifugal microfluidic reactor is used for nanoparticle synthesis: raw material liquids A and B for nanoparticle synthesis are injected into storage bins A and B through material inlet A and material inlet B, respectively; the centrifugal microfluidic reactor is mounted on a centrifuge and subjected to centrifugal reaction, with alternating clockwise and counterclockwise rotations during centrifugation; after the reaction is completed, the centrifugation is stopped, and the product is collected in a mixing chamber, washed, filtered, dried, and ground to obtain nanoparticles. Preferably, the nanoparticles do not include nickel oxide nanoparticles.

[0064] Example 1

[0065] A centrifugal microfluidic reactor, such as Figure 1 and Figure 2 As shown, it includes a cover plate 1, a reaction chip 2 and a bottom plate 3 stacked in sequence from top to bottom.

[0066] like Figure 3 and Figure 4 As shown, the cover plate is disc-shaped and is provided with two A material inlets 11 , two B material inlets 12 , eight screw fixing holes (through which the cover plate is fixed to the reaction chip) and eight ventilation holes 28 .

[0067] like Figure 5 and Figure 6 As shown, the reaction chip is disc-shaped and is provided with two fan-shaped columnar A storage bins 21, two fan-shaped columnar B storage bins 22, four A outlet channels 23, four B outlet channels 24, four mixing channels 25 and four mixing chambers 26. Specifically:

[0068] Two A storage bins and two B storage bins are located in the center of the reaction chip and are spaced apart to form a cylindrical shape. Four mixing chambers are fan-shaped and evenly distributed at the edge of the reaction chip. The mixing chambers are connected to the outlet of a mixing channel through a circular arc-shaped inlet convex cavity 27 located near the top of the reaction chip. Two ventilation holes 28 are provided at the top of each mixing chamber near the center of the reaction chip, penetrating the cover plate. Figure 7 and Figure 8 As shown, the bottom of each mixing chamber is provided with a removable bottom sealing plate 29. The same A and B storage bins are connected to two adjacent A and B outlet channels, and each A outlet channel, B outlet channel, mixing channel and mixing chamber constitute a unit, and the four units are evenly and symmetrically distributed on the reaction chip. In each unit, the A outlet channel and the B outlet channel are symmetrically arranged, and the channel formed by the A outlet channel, the B outlet channel and the mixing channel is Y-shaped (the A outlet channel and the B outlet channel are at a 90° angle), and the connection between the A storage bin and the A outlet channel, and the connection between the B storage bin and the B outlet channel are both provided with a fluid expansion groove 20 with a trumpet-shaped flow path decreasing, and at the same time, the connection end of the A outlet channel and the A storage bin, and the connection end of the B outlet channel and the B storage bin are both curved flow channels; the connection ends of the curved flow channel and the A storage bin and the B storage bin are respectively facing the center of the reaction chip; the connection point between the mixing channel and the mixing chamber is located on the center line of the mixing chamber. The width of the A outlet channel and the B outlet channel is 2mm; the width of the mixing channel is 4mm. The top and bottom of the reaction chip are also provided with screw fixing holes.

[0069] like Figure 9 and Figure 10As shown, the bottom plate is disc-shaped, and four screw fixing holes are provided on its upper surface, which are detachably connected to the reaction chip through screws.

[0070] The cover, reaction chip and base are made of transparent acrylic.

[0071] Simulation test

[0072] Ansys Fluent software was used to simulate the flow and mixing of two different fluids within a centrifugal microfluidic reactor channel. The flow conditions were analyzed from the perspectives of velocity vectors and heat exchange. The simulation model used the volume of fluid method, with energy and gravity enabled. The flow conditions were defined as a turbulent SST k-omega model. A heat exchanger was also included.

[0073] Two fluids, alcohol and water, were specified for the simulation. The water temperature was set to 400K and the alcohol temperature to 300K. Under steady flow conditions, the fluids were flowed at an inlet velocity of 2 m / s. The effects of centrifugal microfluidics were analyzed using a centrifugal rotational speed of 500 rpm, alternating between 1 minute forward and 1 minute reverse rotation for 10 minutes. The velocity vector distribution and phase interactions under the two conditions were compared.

[0074] On the rotating reaction chip, the fluid will be subjected to centrifugal force

[0075] F c =ρrω 2

[0076] Euler force non-uniform speed condition

[0077] F E =ρr*dω / dt

[0078] Coriolis force (density):

[0079] F cr =2ρωv

[0080] Navier-Stokes equations describing momentum motion in viscous fluids

[0081]

[0082] After converting the variant:

[0083]

[0084] Where: p is density, r is radius, ω is angular velocity, t is time, v is velocity, v is velocity vector, p is pressure, and f is the external force per unit volume of fluid. If only gravity is considered, then f = pg, g is gravity, and μ is dynamic viscosity. The force distribution and direction on the reaction chip during centrifugation are as follows: Figure 11 shown.

[0085] Simulation Results

[0086] like Figure 12 As shown in the figure, under the simulation setting conditions, there is no fluid state under centrifugal action, and it can be seen that the fluid flow in the microchannel is in a stable state.

[0087] Figure 13 The velocity vector distributions in the microchannel at 500 rpm for counterclockwise and clockwise rotational speeds are shown. The figure shows that the flow field becomes more unstable, with a significant increase in phase exchange. A high-velocity region is observed at the far end of the mixing channel. In the mixing chamber's inlet convex cavity, the reaction liquid accumulates at high speed at both ends of the convex cavity. This phenomenon is attributed to the periodic fluctuations in the rotational speed.

[0088] Example 2

[0089] In a typical experiment, 0.8g of Ni(NO₃)₂·6H₂O was dissolved in 15ml of deionized water, labeled Solution A. In another beaker, 1.6g of NaOH was dissolved in 20ml of NaClO solution containing 5% active chlorine, labeled Solution B. Using the centrifugal microfluidic reactor described in Example 1, Solution A was injected into two opposing A storage bins, and Solution B was injected into two opposing B storage bins. The centrifugal microfluidic reactor was mounted on a centrifuge. The centrifuge was started and centrifuged at different speeds (using an alternating forward and reverse rotation mode: forward rotation for 1 minute, reverse rotation for 1 minute). Black particles were observed to rapidly form from the two solutions and accumulate in the mixing chamber. After 5 minutes, the centrifuge was shut down, and the bottom plate and the bottom seal of the reaction chip were opened to collect the product. The resulting black precipitate (Ni₂O₃*xH₂O) was further washed repeatedly with NaClO solution and deionized water. After filtration, the final dark black precipitate was placed in a dryer at 90°C for 12 hours, and finally the product was ground to obtain Ni2O3 nanoparticles.

[0090] The chemical reaction formula of the above synthesis process is as follows: 2(Ni(NO3)2·6H2O)+NaclO+4NaOH→Nacl+Ni2O3↓+4Na(NO3)+14H2O

[0091] The nickel precursor Ni(NO3)2·6H2O dissolves in water to generate Ni 2+ and NO3. After that, sodium hypochlorite containing 5% active chlorine will decompose into Na + and ClO - , ClO - It will decompose into Cl - and O2. But under alkaline conditions, ClO - The self-decomposition of ClO is inhibited, and there is more active ClO in the solution. - Then ClO- with Ni 2+ Reaction, ClO - Cl in + ions are reduced to Cl - , while 2Ni 2+ Loses two electrons to become 2Ni 3+ The product of the solution reaction is Ni2O3·xH2O, so it is necessary to heat and dry it to desorb the H2O in the black product.

[0092] Performance Testing

[0093] (1) The morphology and microstructure of Ni2O3 nanoparticles synthesized by microfluidics were characterized using scanning electron microscopy (SEM). Figure 14 The following is a SEM image of NiO nanoparticles obtained under centrifugal conditions of 30 rad / s², 500 rpm, and 5 minutes. The SEM results reveal that the NiO nanoparticles have a complete shape and are bound together to form loose aggregates. Unlike traditional synthesis methods, which typically require several hours, this method shortens the reaction time to just 5 minutes, demonstrating the superior performance of the centrifugal microfluidic process.

[0094] (2) X-ray diffraction (XRD) analysis was used to investigate the crystal structure and purity of the products obtained at different rotation speeds (500 rpm, 1000 rpm, 1500 rpm) (the test samples were directly collected in the mixing chamber without subsequent post-processing). Figure 15 As shown, the synthesis process was 5 minutes without any purification or washing procedures. Therefore, due to the presence of impurities, mainly sodium chloride (NaCl), which is a by-product of the reaction, the XRD results showed impurity peaks. Comparing the three rotation speeds, the 500 rpm group had additional peaks around the main peak of Ni2O3 (31.66°), indicating that the purity of the particles was relatively low. As the rotation speed increased (1000 rpm), the appearance of impurity peaks decreased, and the curve near 31.66° became smoother. In the 1500 rpm group, the curve looked very smooth with little interference, confirming the high purity of the crystal surface.

[0095] (3) The effects of different rotation speeds, accelerations, and times on particle diameter were further analyzed. The statistical method for the diameter of the synthesized Ni2O3 nanoparticles was to use ImageJ to identify spherical particles in the SEM results, randomly select 40 particles from the SEM images, count the particle diameters, and analyze their distribution and curves.

[0096] In order to study the effects of different factors on microfluidic synthesis, the data were divided into 8 groups: 500rpm-5min-4ac, 500rpm-10min-4ac, 1000rpm-5min-4ac, 1000rpm-10min-4ac, 500rpm-5min-8ac, 500rpm-10min-8ac, 1000rpm-5min-8ac, and 1000rpm-10min-8ac, and their effects were analyzed separately. Among them, acceleration 4 and 8 represent the acceleration level, and the actual acceleration is 4.2rad / s2 and 30rad / s2 respectively. Figure 16 and 17 As shown: Figure 17 As shown in (a), at 1000 rpm, the minimum diameter range observed was 100-200 nm. Within this range, the 1000 rpm-10 min-4 ac group exhibited the highest particle counts. Comparing the 1000 rpm-5 min-4 ac group with the 1000 rpm-10 min-4 ac group, it can be seen that with increasing reaction time, the particle size range shifts from larger to smaller. In the 1000 rpm-10 min-4 ac group, approximately 80% of the particles were below 300 nm, while in the 1000 rpm-5 min-4 ac group, only approximately 60% were below 300 nm. Similar results were obtained for the 1000 rpm-5 min-8 ac and 1000 rpm-10 min-8 ac groups, where the diameter range was more concentrated below 400 nm. Notably, in the 1000 rpm-10 min-8 ac group, nearly 90% of the particles were below 400 nm, and the number of particles in this range was the highest, indicating a narrower particle diameter distribution.

[0097] like Figure 17 As shown in (b), at 500 rpm, the highest number of particles in the 500 rpm-10 min-4 ac group was between 200 and 300 nm. Compared to the 500 rpm-5 min-4 ac group, a significant shift in the peak from 300-400 nm to 200-300 nm was observed. This effect became more pronounced when comparing the 500 rpm-5 min-8 ac group with the 500 rpm-10 min-8 ac group. The particle size distribution was broad at 500 rpm-5 min-8 ac, with an average particle size above 580 nm. However, with increasing reaction time, the diameter distribution became more concentrated and shifted to a lower range. With increasing stirring time, the average particle size decreased significantly in the 500 rpm-8 ac and 1000 rpm-8 ac conditions, while the effect was relatively small in the 500 rpm-4 ac and 1000 rpm-4 ac conditions.

[0098] like Figure 17As shown in (c) and (d), under the same reaction time and acceleration, increasing the rotational speed leads to a decrease in particle diameter and a narrower diameter distribution. Under the 5 min 4 ac condition, the 1000 rpm-5 min 4 ac outperforms the 500 rpm-5 min 4 ac. In the 1000 rpm-5 min 4 ac group, over 90% of the particles are smaller than 400 nm, with the majority concentrated around 200 nm. In contrast, for the 500 rpm-5 min 4 ac group, the diameter range is more concentrated between 300 nm and 500 nm. Similar results are obtained for the 500 rpm-5 min 8 ac and 1000 rpm-5 min 8 ac groups, as well as the 500 rpm-10 min 4 ac and 1000 rpm-10 min 4 ac groups.

[0099] In contrast, the acceleration factor exhibited different behavior from the other two factors. Under the 5-min condition, increasing the acceleration from 4 to 8 (representing an increase from 4.2 rad / s² to 30 rad / s²) resulted in an increase in particle diameter. Comparing the 500 rpm-5 min-4 ac and 500 rpm-5 min-8 ac groups, as well as the 1000 rpm-5 min-4 ac and 1000 rpm-5 min-8 ac groups, the diameter distribution range gradually widened with increasing acceleration. Similar results were observed under the 10-min condition, with larger diameters and a wider diameter distribution under the 8 ac condition compared to the 4 ac condition.

[0100] Unless otherwise specified, the raw materials and equipment used in the present invention are commonly used in the art; the methods used in the present invention are conventional methods in the art unless otherwise specified.

[0101] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A centrifugal microfluidic reactor, characterized in that: Including stacked from top to bottom: A cover plate, wherein the cover plate is provided with at least one inlet for material A and at least one inlet for material B; The reaction chip is provided with at least one A storage bin, at least one B storage bin, at least one A outlet channel, at least one B outlet channel, at least one mixing channel, and at least one mixing chamber; the A storage bin and the B storage bin are located in the center of the reaction chip and are arranged alternately; the mixing chamber is located at the edge of the reaction chip; the A material inlet / B material inlet, the A storage bin / B storage bin, the A outlet channel / B outlet channel, the mixing channel, and the mixing chamber are sequentially connected; base plate; The mixing chamber is connected to the outlet end of the mixing channel through the inlet convex cavity located at the top; the mixing chamber is fan-shaped, and the inlet convex cavity is arc-shaped and located near the edge of the reaction chip.

2. The centrifugal microfluidic reactor according to claim 1, wherein: The reaction chip is disc-shaped and is provided with multiple A storage bins, B storage bins, A outlet channels, B outlet channels, mixing channels and mixing chambers; and each A outlet channel, B outlet channel, mixing channel and mixing chamber constitutes a unit; multiple units are evenly and symmetrically distributed on the reaction chip.

3. The centrifugal microfluidic reactor according to claim 2, wherein: In each of the units, outlet channel A and outlet channel B are symmetrically arranged, and the channel formed by outlet channel A, outlet channel B and mixing channel is Y-shaped; the connection point between the mixing channel and the mixing chamber is located on the center line of the mixing chamber.

4. The centrifugal microfluidic reactor according to claim 3, wherein: The connecting end between the A outlet channel and the A storage bin, and the connecting end between the B outlet channel and the B storage bin are both curved flow channels; the connecting ends between the curved flow channel and the A storage bin and the B storage bin are respectively facing the center of the reaction chip; the A outlet channel and the B outlet channel form an angle of 85-95°.

5. The centrifugal microfluidic reactor according to any one of claims 1 to 4, characterized in that: The width of the outlet channel A and the outlet channel B is 0.5-3 mm; the width of the mixing channel is 1-6 mm, and the width of the outlet channel A and the outlet channel B is smaller than the width of the mixing channel.

6. The centrifugal microfluidic reactor according to any one of claims 1 to 4, characterized in that: The connection between the A storage bin and the A outlet channel, and the connection between the B storage bin and the B outlet channel are both provided with a trumpet-shaped fluid expansion groove with a decreasing flow path.

7. The centrifugal microfluidic reactor according to any one of claims 1 to 4, characterized in that: At least one ventilation hole is provided on the top of each mixing chamber in the reaction chip and the cover plate.

8. The centrifugal microfluidic reactor according to claim 7, wherein: The ventilation hole is located in the mixing chamber near the center of the reaction chip.

9. The centrifugal microfluidic reactor according to any one of claims 1 to 4, characterized in that: The reaction chip is provided with a detachable bottom sealing plate at the bottom of the mixing chamber.

10. Use of the centrifugal microfluidic reactor according to any one of claims 1 to 9 in nanoparticle synthesis.

11. The use according to claim 10, characterized in that include: The raw material liquid A and the raw material liquid B for nanoparticle synthesis are injected into the A storage bin and the B storage bin through the A material inlet and the B material inlet respectively; The centrifugal microfluidic reactor is fixed on a centrifuge and subjected to centrifugal reaction, with clockwise and counterclockwise rotations performed alternately during the centrifugation. After the reaction is completed, the centrifugation is stopped, and the product is collected in the mixing chamber. After washing, filtering, drying, and grinding, nanoparticles are obtained.

12. The use according to claim 10 or 11, characterized in that: The nanoparticles are nickel oxide nanoparticles.

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