Preparation method of microfluidic phase change cooling liquid

Abstract

The invention discloses a preparation method of a microfluidic phase change cooling liquid, and belongs to the technical field of advanced thermal management material preparation. According to the method, a specific microfluidic flow and functional fluid are designed, and a molten phase-change material fluid, a shell fluid containing curable resin and a heat-conducting filler and a cooling base fluid insoluble in a shell are pumped into a microfluidic chip respectively. In a chip flow channel, under the action of hydrodynamic force and interfacial tension, shell layer fluid wraps phase change material fluid in situ, and monodisperse core-shell liquid drops are formed and dispersed in base fluid. And then guiding the liquid drops to pass through a curing area, so that the shell layer is cured in the flowing process, and a suspension system with the phase change microcapsules dispersed in the base solution is directly obtained. According to the invention, accurate control of the size of the phase change microcapsule and the thickness of the shell layer is realized, and the preparation method of the phase change cooling liquid which is continuous, efficient and controllable in structure is provided.

Description

Technical Field

[0001] This invention relates to the field of advanced thermal management material preparation technology, and more specifically, to a method for preparing a microfluidic phase change coolant. Background Technology

[0002] With the continuous increase in the power density of electronic devices, especially the surge in computing power demands of data center servers, efficient heat dissipation technology has become crucial. Traditional air cooling is gradually approaching its heat dissipation limits, while liquid cooling technology, especially phase change liquid cooling technology that utilizes the latent heat of phase change for heat exchange, has attracted widespread attention due to its higher heat dissipation efficiency. The core of phase change coolant lies in dispersing phase change materials (PCMs) in a stable form within the coolant base fluid, allowing them to undergo a phase change within the operating temperature range to absorb a large amount of heat.

[0003] Existing phase change coolant preparation technologies mainly fall into two categories, but both have certain limitations. The first category involves directly physical blending solid-solid or solid-liquid phase change materials, thermally conductive particles, and a liquid base fluid (e.g., the scheme disclosed in Chinese patent CN115181550A). This method is simple in process, but the direct contact between the phase change material and the coolant, under long-term thermal cycling and fluid shearing, can easily lead to problems such as phase change material leakage, particle agglomeration, or decreased compatibility with the base fluid, affecting the long-term reliability and stability of the cooling system.

[0004] The second type of method involves pre-encapsulating the phase change material into microcapsules and then dispersing them in a base liquid (e.g., the scheme disclosed in Chinese patent CN118834666A). While this method improves encapsulation stability to some extent, the preparation of these microcapsules typically relies on macroscopic batch processing techniques such as emulsification, coating, pulverization, and sieving. These processes make it difficult to precisely control the size distribution, shell thickness, and structural integrity of the microcapsules, resulting in poor batch consistency. Furthermore, the complex multi-step post-processing makes the process cumbersome, energy-intensive, and difficult to achieve continuous and large-scale production. Therefore, a method for preparing microfluidic phase change coolant is proposed to address the above problems. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a microfluidic phase change coolant preparation method to solve the defects of existing phase change coolant preparation technology, such as easy leakage of phase change materials, uncontrollable size and structure of microcapsules, and complex and discontinuous preparation process.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a microfluidic phase change coolant, comprising the following steps: S1. Provide a molten phase change material fluid as the core phase fluid to provide latent heat of phase change for the coolant; S2. Provide a mixed fluid containing a curable resin and a thermally conductive filler as a shell fluid, wherein the curable resin is photocurable or thermocurable, for encapsulating the core phase fluid and forming a thermally conductive path. S3. Provide a coolant that is immiscible with the shell fluid as a continuous phase fluid for use as a dispersion medium and heat transfer medium. S4. The core phase fluid, shell fluid and continuous phase fluid are simultaneously introduced into a microfluidic chip at controllable flow rates Vc, Vs and Vf respectively. The flow rates Vc, Vs and Vf are independently adjustable. By controlling the fluid dynamics and interfacial tension, the shell fluid wraps the core phase fluid to form monodisperse core-shell droplets and disperses them in the continuous phase fluid. S5. Guide the fluid containing the core-shell droplets through a solidification zone, so that the shell fluid undergoes a solidification reaction during the flow process to form a structurally complete solid shell. S6. Collect the suspension containing the solidified phase change microcapsules that flows out of the solidification zone as the phase change coolant.

[0007] Furthermore, step S1 includes: heating and melting an organic material with a phase transition temperature between 30°C and 60°C, a temperature range suitable for the heat dissipation conditions of typical electronic devices; and maintaining the temperature at 10°C to 40°C above the phase transition temperature to ensure that the material remains in a molten state and has suitable fluidity; or, while maintaining the molten state, adding and dispersing surface-treated thermally conductive particles with an average particle size of 10nm to 200nm to enhance the thermal conductivity of the core phase itself.

[0008] Furthermore, the surface-treated thermally conductive particles are treated with a silane coupling agent having a C8-C18 alkyl chain, and the amount of the treatment agent is 0.5% to 3% of the mass of the thermally conductive particles. The surface treatment is used to improve the wettability and dispersion stability of the thermally conductive particles in the organic phase change material melt.

[0009] Furthermore, step S2 includes: mixing the curable resin with a sheet-like thermally conductive filler having an aspect ratio greater than 50, which helps to form an efficient thermally conductive network within the shell; the filler having a mass percentage of 5% to 35% in the mixed fluid to balance the thermal conductivity, mechanical strength, and flowability of the shell; followed by degassing and homogenization treatment to ensure the uniformity and processability of the shell fluid.

[0010] Furthermore, in step S4, the flow channel of the microfluidic chip is a flow focusing structure, which is conducive to achieving a stable encapsulation flow pattern; The flow rates Vc, Vs, and Vf satisfy the following conditions: 1 μL / min ≤ Vc ≤ 15 μL / min, 2 μL / min ≤ Vs ≤ 50 μL / min, and 50 μL / min ≤ Vf ≤ 800 μL / min. This flow rate range works synergistically to ensure the monodispersity of the generated droplets and the stability of the process.

[0011] Furthermore, during step S4, the temperature along the path through which the nucleus fluid flows is kept constant. This constant temperature is at least 15°C higher than the phase change temperature of the phase change material in the nucleus fluid, in order to prevent the nucleus fluid from undergoing phase change solidification in the microchannel and to ensure the continuity and smoothness of the process.

[0012] Furthermore, in step S5, the curing zone is a tubular channel connecting the outlet of the microfluidic chip; when using a photocurable resin, an ultraviolet light source with a wavelength of 355nm to 405nm and a light intensity of 10mW / cm² to 200mW / cm² is used to uniformly irradiate along the length of the tubular channel to initiate the photopolymerization reaction of the resin; when using a thermocurable resin, the tubular channel is placed in a constant temperature environment of 60°C to 120°C to provide the activation energy required for the thermocuring of the resin.

[0013] Furthermore, in step S5, by adjusting the total flow rate of the fluid, the residence time of the core-shell droplets in the curing zone is controlled to be between 30 seconds and 300 seconds. This time range is designed to ensure that the shell material can fully complete the curing reaction.

[0014] Furthermore, after step S6, step S7 is included: adding a dispersant to the collected suspension and stirring at low speed. The dispersant is a polyether-modified silicone oil or a block copolymer, and its addition amount is 0.01% to 0.5% of the total mass of the suspension. The stirring speed is 50 rpm to 300 rpm, and the stirring time is 10 minutes to 60 minutes. This step helps the dispersant molecules adsorb onto the surface of the microcapsules, thereby improving the long-term storage stability of the suspension.

[0015] Furthermore, after step S7, step S8 is also included: determining the mass concentration of the phase change microcapsules in the suspension, and adjusting its final mass concentration to a target range of 2% to 12% by adding the continuous phase fluid. This step is used to standardize product performance so that it meets the requirements of latent heat of phase change in different heat dissipation scenarios.

[0016] The technical effects and advantages of this invention are as follows: To address the issues of easy leakage and uncontrollable microcapsule structures in phase change materials (PCMs), this invention utilizes microfluidic technology as the core fabrication platform to achieve precise construction of PCM microcapsule structures. The method first prepares the PCM, encapsulation precursor, and thermally conductive components into functional fluids. Then, leveraging the precise manipulation capabilities of multiphase fluids within a microfluidic chip, the encapsulation shell fluid stably and in situ encapsulates the PCM core fluid at a microscale, forming core-shell droplets with uniform size and height. By independently adjusting the pumping flow rate of each phase fluid, the diameter of the generated droplets and the shell thickness can be linearly and programmably controlled. Subsequently, online curing technology rapidly solidifies the shell. This process ensures the density and integrity of the shell, effectively isolating the PCM from the external base fluid, improving potential leakage and compatibility issues during long-term use, and enabling predictable and reproducible product structure preparation.

[0017] To address the challenges of complex and discontinuous preparation processes, this invention provides a continuous flow preparation scheme from raw materials to finished product. All steps are completed sequentially within the flow system, eliminating the need for cumbersome post-processing operations such as intermittent emulsification, repeated freeze-pulverization, centrifugation, and drying required in traditional methods. This continuous process design simplifies production steps, reduces instability caused by material transfer and equipment start-up and shutdown, and contributes to improved production efficiency and product consistency. Furthermore, the method employs mild reaction conditions, with the main energy input concentrated in specific stages of heat preservation and curing, providing a feasible foundation for subsequent process scale-up and large-scale production.

[0018] Furthermore, the preparation method provided by this invention also possesses excellent flexibility and adaptability. By adjusting the specific composition of the input functional fluid, such as changing the core material for different phase change temperatures or altering the type and proportion of thermally conductive fillers in the shell, phase change coolant products suitable for different temperature zones and exhibiting different thermophysical properties can be customized and prepared within the same process framework. Based on the precise control characteristics of microfluidics, the prepared microcapsules exhibit high monodispersity, which helps them form a stable suspension system in the base fluid, reducing sedimentation or aggregation caused by excessive size differences, thereby improving the storage and use stability of the final coolant product. Attached Figure Description

[0019] Figure 1 This is a flowchart of the overall continuous process of the preparation method of the present invention.

[0020] Figure 2 This is a flowchart of the microfluidic core-shell droplet generation process of the present invention.

[0021] Figure 3 A branch structure diagram is selected for the shell curing method of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0023] As attached Figures 1 to 3 This paper presents a method for preparing a microfluidic phase change coolant. The method involves continuously preparing core-shell structured phase change microcapsules using microfluidic technology and dispersing them in a cooling base fluid to form a suspension system. The following specific examples illustrate each step of this method.

[0024] Example 1: Preparation method based on photocurable resin As one implementation method, this embodiment describes the preparation process of using a photocurable resin as the shell material.

[0025] Step S1: Provide the nucleus phase fluid.

[0026] Select phase transition temperature as Refined paraffin wax at a temperature between 30°C and 60°C was used as an organic phase change material. It was placed in a reaction vessel equipped with heating and stirring functions and heated to... The temperature is ℃, which is 30℃ higher than its phase transition temperature, falling within the range of 10℃ to 40℃ above the phase transition temperature. It is maintained by a temperature control device. Temperature allows the paraffin to completely melt and remain in a low-viscosity liquid state.

[0027] Composite reinforcement treatment is performed. An average particle size of [missing information] is added to the above molten paraffin. Nano-sized alumina particles (nm in diameter) were pre-treated with octyltriethoxysilane at a concentration of 1.5% of the alumina particle mass, ranging from 0.5% to 3%. This treatment was applied while maintaining... Under the given temperature conditions, first at the stirring speed Mechanical stirring is performed at rpm for a duration of [time missing]. min, then use an ultrasonic processor with power W undergoes ultrasonic treatment for a duration of [duration missing]. min.

[0028] This process enables the uniform dispersion of nano-alumina particles without visible agglomeration, thereby obtaining a homogeneous composite nucleus-phase fluid. After preparation, the fluid is transferred to storage tank A with an independent temperature control system and connected to subsequent injection pump A via insulated piping. Storage tank A and the entire delivery pipeline are maintained at a constant temperature. Temperature is adjusted to keep the nucleus fluid in a molten state during subsequent steps.

[0029] Step S2: Provide shell fluid.

[0030] A UV-curable acrylate prepolymer was selected as the curable resin matrix. The prepolymer was weighed... g, add g-shaped boron nitride nanosheets were used as a thermally conductive filler, comprising 10% by mass in the shell fluid, ranging from 5% to 35%. The average lateral dimension of the boron nitride nanosheets was [missing information]. μm, average thickness is nm, its aspect ratio It meets the requirement that the aspect ratio is greater than 50.

[0031] Place the mixture in a vacuum planetary mixer. When the vacuum level reaches... Under the condition of MPa, at the rotational speed High-speed shear dispersion is performed at rpm for a duration of [time value missing]. This process achieves uniform dispersion of the filler and removes air bubbles, resulting in a homogeneous shell fluid of suitable viscosity. After preparation, the shell fluid is transferred to a light-shielded storage tank B and connected to the subsequent injection pump B via piping.

[0032] Step S3: Provide a continuous phase fluid.

[0033] Select kinematic viscosity value The dimethyl silicone oil in cSt serves as the continuous phase fluid (coolant), which is immiscible with the acrylate-based shell fluid prepared in step S2. The continuous phase fluid is stored in a storage tank C and connected to a subsequent injection pump C via piping.

[0034] Step S4: Microfluidic generation of core-shell droplets.

[0035] A PDMS microfluidic chip with a standard flow focusing structure is used. This chip has three inlets, corresponding to the core phase, shell phase, and continuous phase fluid, respectively. The flow channels within the chip form a width in the focusing region. A square channel of μm.

[0036] Three independently controlled, high-precision injection pumps are used to pump the nucleus fluid from storage tank A, the shell fluid from storage tank B, and the continuous phase fluid from storage tank C into the corresponding inlets of the microfluidic chip at constant flow rates via their respective insulated or ambient temperature pipelines. The specific flow rate settings are as follows: flow rate of nucleus phase fluid μL / min; Flow rate of the shell fluid μL / min; Flow rate of continuous phase fluid μL / min.

[0037] This set of parameters meets the following range: , ,and (Units are all μL / min). Meanwhile, the flow rate ratio... It is between 1.5 and 5; Flow rate ratio It is between 20 and 100.

[0038] In this flow focusing structure, by adjusting the flow rate , , This allows for a higher flow rate ratio between the intermediate phase (shell fluid) and the inner phase (core fluid). The ratio of the flow rate of the external phase (continuous phase fluid) to the sum of the two ( ) Under specific conditions, the internal phase is stably encapsulated by the intermediate phase under the balance of hydrodynamics and interfacial tension, forming a core-shell droplet.

[0039] These flow rate parameters can be determined through preliminary systematic experiments, which aim to generate monodisperse droplets with diameters of [missing information]. The goal is to stabilize the micrometer between 100μm and 150μm, by adjusting... , , It is obtained by observing the droplet formation state.

[0040] Both the pipeline pumping the nucleus fluid and the microfluidic chip itself are equipped with independent temperature control devices to maintain the temperature at a certain level. The temperature is ℃, which is 32℃ higher than the phase change temperature of paraffin, and meets the requirement of being more than 15℃ higher than the phase change temperature, so that the nucleus fluid can remain in a molten state in the flow channel.

[0041] In the flow-focusing region of the chip, the high-speed flowing continuous phase fluid shears and compresses the shell fluid of the intermediate phase and the core fluid of the central phase. Under specific channel geometry and flow rate ratio, the shell fluid encapsulates the core fluid, forming a composite droplet of "paraffin / alumina core-acrylate / boron nitride shell", which is then dispersed in the continuous phase fluid.

[0042] Step S5: Guide curing.

[0043] The fluid containing core-shell droplets flowing out of the chip outlet is directly introduced into a section with an inner diameter of [missing information - likely a diameter value]. mm, length is A transparent fluorinated ethylene propylene copolymer tube (cm) serves as the curing zone.

[0044] In this embodiment, the shell fluid is photocurable. A center wavelength of [wavelength value missing] is used. A UV LED strip with a wavelength of 355nm to 405nm was used as the UV light source. The LED strips were arranged in parallel and fixed to an aluminum heat sink 2cm from the outer wall of the FEP tube. The inner surface of the heat sink was coated with a reflective layer to ensure that the UV light irradiated the fluid flowing through the tubular channel along its length. The average irradiance measured at the tube wall using a UV radiometer was calibrated to [value missing]. The intensity is in the range of 10 mW / cm² to 200 mW / cm².

[0045] Residence time of core-shell droplets in the solidification zone It is a process parameter that needs to be controlled and must meet the requirements of 30s to 300s.

[0046] By adjusting the total flow rate ( The residence time is controlled by the flow rate (μL / min) and the size of the solidification channel. s, meets the requirements. In the stated Within a given time, ultraviolet light induces a polymerization and cross-linking reaction of acrylates in the shell fluid, causing it to solidify into a polymer shell, thus obtaining phase change microcapsules. The completeness of solidification can be preliminarily judged by taking a sample at the outlet, observing the regularity of the microcapsule morphology under an optical microscope, and adding a small amount of acetone to observe whether swelling occurs.

[0047] Step S6: Collect the suspension.

[0048] At the outlet of the transparent tube, a clean, wide-mouthed container is used to collect the outflowing suspension. This suspension is a crude product of phase change coolant containing solid phase change microcapsules, denoted as intermediate product P1.

[0049] Step S7: Add dispersant for stabilization.

[0050] To improve the suspension stability of the microcapsules, a post-processing step was performed. 0.1% (by weight) of polyether-modified silicone oil was added to intermediate P1 as a dispersant, with the addition amount ranging from 0.01% to 0.5%. The mixture was then transferred to a stirring tank and stirred at a controlled stirring speed. Stir at low speed (rpm). min, so that the dispersant is adsorbed onto the surface of the microcapsules, and product P2 is obtained.

[0051] Step S8: Concentration fine-tuning.

[0052] To adjust the microcapsule concentration to the standard value, a sample was first taken from product P2, and the current mass concentration of phase change microcapsules was determined using the centrifugation-drying-weighing method. For example, a certain mass of sample can be taken, centrifuged, washed to remove free components, and dried to constant weight. The mass percentage of the precipitate can then be calculated to obtain the final product. Assuming the measurement is... %.

[0053] Set the target mass concentration of the final product The percentage is between 2% and 12%. Based on the law of conservation of mass, the mass of the continuous phase fluid to be added to product P2 is calculated. Under gentle stirring, the calculated amount of silicone oil is added to the mixing vessel via a metering pump.

[0054] After adding the additive, continue stirring for approximately 15 minutes to ensure thorough mixing. A second sample can be taken to verify the concentration and confirm that the final mass concentration has been adjusted to the desired level. %. This completes the production of the final usable microfluidic phase change coolant product E1.

[0055] Example 2: Preparation method based on thermosetting resin As another implementation method, the main difference between this embodiment and Embodiment 1 lies in the shell curing method.

[0056] Steps S1 and S3 are the same as in Example 1.

[0057] Step S2: Prepare (thermosetting) shell fluid.

[0058] A two-component thermosetting epoxy resin was selected as the curable resin matrix. The mixed resin matrix was homogenized and dispersed with 20% by mass of sheet graphene in a vacuum planetary mixer to obtain a shell fluid. This fluid was then stored in storage tank D.

[0059] Step S4: Microfluidic generation of core-shell droplets.

[0060] The microfluidic process is similar to that in Example 1, using the same flow focusing chip.

[0061] The flow rate parameter is adjusted as follows: μL / min, μL / min, μL / min.

[0062] Step S5: Online thermosetting.

[0063] The generated core-shell droplet is introduced into a section with an inner diameter of [missing information]. mm, length A stainless steel serpentine coil of cm was used as the curing zone. The entire stainless steel coil was immersed in a temperature set at a specific temperature. In a constant temperature oil bath at ℃.

[0064] Residence time of droplets in hot runner Requirements must be met. This can be achieved by adjusting the total flow rate. The residence time is controlled by the flow rate (μL / min) and the size of the solidification channel. The requirements are met. During this process, the epoxy resin system undergoes a thermosetting cross-linking reaction to form a solid shell.

[0065] Steps S6 to S8: Same as in Example 1, finally product E2 is obtained.

[0066] Example 3: Preparation of a phase change material using lauric acid As a variation of the implementation, this embodiment demonstrates the adjustment process of the method when using materials with different phase transition temperatures. When the core material changes, its fluid properties may change; therefore, the flow rate parameters can be fine-tuned through similar preliminary experiments to adapt to the new fluid system.

[0067] Step S1: Provide the nucleus phase fluid.

[0068] Selecting the phase transition temperature Lauric acid at ℃ is used as an organic phase change material. It is heated to... The temperature was maintained at ℃ and kept at the melt. Subsequent composite reinforcement and other treatments were similar to those in Example 1.

[0069] Steps S2 and S3: Same as in Example 1, the shell fluid still uses a photocuring system.

[0070] Step S4: Microfluidic generation of core-shell droplets.

[0071] The same flow-focusing chip was used. Due to the low phase transition temperature of lauric acid, the nucleus phase fluid holding temperature was... Set to 50℃ (higher) (15℃). The flow rate parameter can be fine-tuned with reference to Example 1, for example, set as follows: μL / min, μL / min, μL / min was used to generate core-shell droplets of uniform size.

[0072] Step S5: Guide curing.

[0073] The curing conditions were the same as in Example 1, using the same curing flow channel ( mm, cm). By adjusting the total flow rate ( μL / min), controlling residence time s, meets the requirements.

[0074] Steps S6 to S8: Same as in Example 1. The final product, phase change coolant E3, can be obtained.

[0075] Those skilled in the art will understand that various changes and modifications can be made to the above embodiments without departing from the spirit and scope defined by the present invention. For example, the specific configuration of the microfluidic chip, the type and combination of thermally conductive fillers, and the method of applying curing energy can all be selected and adjusted.

Claims

1. A method for preparing a microfluidic phase change coolant, characterized in that, Includes the following steps: S1. Provide a molten phase change material fluid as the core phase fluid; S2. Provide a mixed fluid containing a curable resin and a thermally conductive filler as a shell fluid, wherein the curable resin is a photocurable or thermocurable type; S3. Provide a coolant that is immiscible with the shell fluid as a continuous phase fluid; S4. The core phase fluid, shell fluid and continuous phase fluid are simultaneously introduced into a microfluidic chip at controllable flow rates Vc, Vs and Vf respectively. The flow rates Vc, Vs and Vf are independently adjustable to control the size of the core-shell droplets, so that the shell fluid wraps the core phase fluid to form core-shell droplets and disperses them in the continuous phase fluid. S5. Guide the fluid containing the core-shell droplets through a solidification zone to solidify the shell fluid; S6. Collect the suspension containing the solidified phase change microcapsules that flows out of the solidification zone.

2. The method for preparing microfluidic phase change coolant according to claim 1, characterized in that, Step S1 includes: heating and melting an organic material with a phase change temperature between 30°C and 60°C, and maintaining the temperature at 10°C to 40°C above the phase change temperature; or, while maintaining the molten state, adding and dispersing surface-treated thermally conductive particles with an average particle size of 10nm to 200nm.

3. The method for preparing microfluidic phase change coolant according to claim 2, characterized in that, The surface-treated thermally conductive particles are surface-treated with a silane coupling agent having a C8-C18 alkyl chain, and the amount of the surface-treated agent is 0.5% to 3% of the mass of the thermally conductive particles.

4. The method for preparing microfluidic phase change coolant according to claim 1, characterized in that, Step S2 includes: mixing the curable resin with a sheet-like thermally conductive filler, wherein the sheet-like thermally conductive filler has an aspect ratio greater than 50 and a mass percentage of 5% to 35% in the mixed fluid, followed by degassing and homogenization treatment.

5. The method for preparing microfluidic phase change coolant according to claim 1, characterized in that, In step S4, the flow channel of the microfluidic chip is a flow focusing structure; The flow rates Vc, Vs, and Vf satisfy the following conditions: 1 μL / min ≤ Vc ≤ 15 μL / min, 2 μL / min ≤ Vs ≤ 50 μL / min, and 50 μL / min ≤ Vf ≤ 800 μL / min.

6. The method for preparing microfluidic phase change coolant according to claim 5, characterized in that, When performing step S4, the temperature along the path through which the nucleus fluid flows is kept constant, and this constant temperature is at least 15°C higher than the phase transition temperature of the phase change material in the nucleus fluid.

7. The method for preparing microfluidic phase change coolant according to claim 1, characterized in that, In step S5, the curing area is a tubular channel connecting the outlet of the microfluidic chip; when using a photocurable resin, an ultraviolet light source with a wavelength of 355nm to 405nm and a light intensity of 10mW / cm² to 200mW / cm² is used to uniformly irradiate along the length of the tubular channel; when using a thermocurable resin, the tubular channel is placed in a constant temperature environment of 60℃ to 120℃.

8. The method for preparing microfluidic phase change coolant according to claim 7, characterized in that, In step S5, the residence time of the core-shell droplets in the solidification zone is controlled to be between 30 seconds and 300 seconds by adjusting the total flow rate of the fluid.

9. The method for preparing microfluidic phase change coolant according to claim 1, characterized in that, Following step S6, step S7 is further included: adding a dispersant to the collected suspension and stirring at low speed. The dispersant is polyether-modified silicone oil or a block copolymer, and its addition amount is 0.01% to 0.5% of the total mass of the suspension. The stirring speed is 50 rpm to 300 rpm, and the stirring time is 10 minutes to 60 minutes.

10. The method for preparing microfluidic phase change coolant according to claim 9, characterized in that, Following step S7, step S8 is also included: determining the mass concentration of the phase change microcapsules in the suspension, and adjusting its final mass concentration to the target range of 2% to 12% by adding the continuous phase fluid.

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