High-viscosity and high-elasticity polymer emulsion droplet and method for reinforced preparation by pulsating flow

Abstract

The invention discloses a high-viscosity and high-elasticity polymer emulsion liquid drop and a pulsating flow enhanced preparation method, and belongs to the technical field of micro-chemical engineering, and the method comprises the following steps: respectively preparing a polymer dispersed phase solution and a continuous phase solution, introducing a micro-fluidic chip, and applying pulsating flow in the micro-fluidic chip to act on the continuous phase solution, so as to obtain the high-viscosity and high-elasticity polymer emulsion liquid drop. Further collecting the generated polymer emulsion liquid drops; the micro-fluidic chip comprises a sealing cover layer, a chip layer and a substrate layer which are sequentially arranged from top to bottom, the chip layer is provided with a T-shaped microchannel or a flow focusing microchannel. By introducing the pulsating flow technology, the problems of stability and uniformity in the high-viscosity and high-elastic polymer emulsion droplet generation process are effectively solved, and the droplet generation quality is remarkably improved. According to the invention, accurate control of liquid drop generation is realized, the frequency and size of the liquid drops can be accurately adjusted, the sizes of the liquid drops are consistent, and the device is suitable for solutions with various rheological properties, and has wide potential application values in the fields of chemical engineering, medicines, foods and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-chemical engineering, and in particular relates to a high-viscosity and high-elastic polymer emulsion droplet and a method for intensifying the preparation thereof by utilizing pulsating flow. Background Art

[0002] In the field of microchemical technology, emulsion droplet generation is an important step in realizing a variety of chemical processes. However, traditional methods usually rely on microchannel systems with constant flow rates, which face significant challenges when dealing with high-viscosity and high-elasticity polymer solutions. Due to the complex rheological properties of these solutions, it is difficult to achieve stable and uniform droplet formation under conventional flow conditions. In addition, when dealing with high-viscosity solutions, traditional methods are particularly prominent due to insufficient shear force, resulting in uneven droplet size and low system efficiency.

[0003] The serial confinement technology proposed in patent CN115228515B regulates the size distribution of the dispersed phase in a multiphase system through a unique physical structure. The device uses the alternating arrangement of confined channels and intermediate channels to achieve droplet size control through the extrusion and pulsating impact of the continuous phase. However, the complex structure and potential high manufacturing cost of the device may limit its practical application. In addition, the excessively small confined channel size may cause clogging problems of high-viscosity and high-elastic polymer droplets, thereby affecting its application in high-viscosity and high-elastic fluids. Patent CN114160218A uses surface acoustic wave technology to prepare monodisperse non-Newtonian droplets. Although this technology performs well in generating non-Newtonian droplets of uniform size, the high requirements for equipment accuracy and operating conditions may limit its feasibility. The application of surface acoustic wave technology may increase the complexity and energy consumption of the system, especially in large-scale applications, these factors may have an adverse effect on the overall cost and operating efficiency. Therefore, although it has advantages in specific applications, it is necessary to weigh equipment requirements and operating costs when it is widely used.

[0004] In this context, current technologies still face some significant challenges in dealing with droplet generation of highly viscous and highly elastic polymer solutions. The main problems include the difficulty in achieving stable and uniform droplet formation, and the difficulty in controlling droplet size and generation frequency. In high viscosity and high elasticity environments, existing methods often make it difficult to generate droplets or make them uneven in size due to insufficient shear force, thereby reducing system efficiency. In addition, complex equipment structures and high manufacturing costs have also become obstacles to their widespread application. Especially in the pursuit of on-demand preparation of droplets, the flexibility and controllability of existing technologies still need to be improved. These problems urgently need to be solved through innovative technical solutions to improve the efficiency and applicability of droplet generation. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a high-viscosity and high-elastic polymer emulsion droplets and a method for preparing them using pulsating flow enhancement, so as to solve the technical problem of how to improve the stability and uniformity of the generation of high-viscosity and high-elasticity emulsion droplets, while achieving the controllability of droplet generation frequency and size, and simplifying the system structure and reducing costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a method for preparing high-viscosity and high-elastic polymer emulsion droplets by utilizing pulsating flow intensification, comprising the following steps: A polymer dispersed phase solution and a continuous phase solution are prepared respectively, and a pulsating flow is applied to the continuous phase solution by introducing the microfluidic chip, and then the generated high-viscosity and high-elastic polymer emulsion droplets are collected; The microfluidic chip comprises a capping layer, a chip layer and a base layer which are arranged in sequence from top to bottom; the chip layer is provided with a T-shaped microchannel or a flow focusing microchannel.

[0007] Preferably, the microfluidic chip is connected to a pressure pump for regulating the periodic change of the flow rate of the continuous phase solution; The microfluidic chip is connected to a syringe pump for delivering the polymer dispersed phase solution at a constant speed; The microfluidic chip is connected to a pressure sensor for real-time monitoring of pressure changes in the system; The size of the microfluidic chip is (100-200) × (50-100) mm.

[0008] Further preferably, the pulsating flow is achieved by controlling the periodic change of the fluid flow rate; the pulsating flow uses a pressure pump to apply pressure to the continuous phase solution; the pulsating flow has a pulsating frequency of 0-250 Hz, a velocity amplitude of 12 μL / min, and an initial velocity of 12 μL / min.

[0009] Preferably, the polymer dispersed phase solution is a carbomer gel solution; the flow rate is controlled at 12-24 μL / min; The carbomer gel solution is prepared by mixing carbomer 940 powder and deionized water in a mass ratio of 1: (100-1500), stirring for 2-5 hours, and then adding NaOH solution and stirring until a transparent gel network is formed; The continuous phase solution is prepared by stirring the surfactant Span 85 and mineral oil in a mass ratio of 1:20 until they are fully mixed.

[0010] Preferably, the diameter of the T-shaped microchannel or the flow focusing microchannel is 0.1-1 mm.

[0011] Preferably, the length of the T-shaped microchannel or flow focusing microchannel is 100-200 times of its height, the width is 0.05-1 mm, and the aspect ratio is 0.1-10.

[0012] Preferably, the viscosity of the polymer dispersed phase solution is 2000-10000 centipoise, and the relaxation time is 0.1-1 s.

[0013] Preferably, the size of the high-viscosity and high-elastic polymer emulsion droplets is controlled by adjusting the pulsation frequency, amplitude and flow rate.

[0014] Preferably, the cover layer has a liquid inlet and a liquid outlet communicating with the chip layer and the base layer; the thickness of the cover layer, the chip layer and the base layer are all 2-4 mm.

[0015] The invention also discloses a high-viscosity and high-elastic polymer emulsion droplet, which is prepared by the above-mentioned method for preparing the high-viscosity and high-elastic polymer emulsion droplet by utilizing pulsating flow intensification.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for preparing high-viscosity and high-elastic polymer emulsion droplets using pulsating flow enhancement. By introducing pulsating flow technology, the stability and uniformity problems encountered in the generation process of high-viscosity and high-elastic polymer emulsion droplets are effectively solved, and the generation quality of droplets is significantly improved. The method realizes precise control of droplet generation, and can accurately adjust the frequency and size of droplets, so that the droplet size is more consistent, thereby better meeting the diverse needs of different application scenarios. In addition, compared with other complex droplet preparation technologies, the system design of the present invention is relatively simple, which not only simplifies the system structure, but also greatly reduces the manufacturing cost and improves practicality. The method can adapt to solutions with a variety of rheological properties, further expanding its scope of application, and has a wide range of potential application value in the fields of chemical industry, medicine, food, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the composition of the droplet preparation system based on continuous phase velocity pulsation disclosed in the present invention.

[0018] Figure 2 It is a three-dimensional exploded schematic diagram of the microfluidic chip of the present invention.

[0019] Figure 3 These are images of liquid droplets at different pulsation frequencies disclosed in Example 1 of the present invention; wherein (a) is 0 Hz; (b) is 75 Hz; and (c) is 175 Hz.

[0020] Figure 4 Schematic diagram of the effect of different pulsation frequencies on droplet volume and droplet generation frequency disclosed in Example 2 of the present invention; wherein (a) is the droplet volume; and (b) is the droplet generation frequency.

[0021] Figure 5 This is the effect of different flow rates of the polymer dispersed phase on the volume and generation frequency of droplets disclosed in Example 3 of the present invention.

[0022] In the figure: 1. microfluidic chip; 2. collection container; 3. computer; 4. injection pump; 5. pressure pump; 6. continuous phase solution; 7. pressure sensor; 8. capping layer; 9. chip layer; 10. base layer; 11. flow focusing microchannel; 12. T-type microchannel. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the present invention, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0025] In the present invention, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0026] In the present invention, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0027] In the present invention, unless otherwise specified, the components or preferred components involved can be combined with each other to form a new technical solution.

[0028] In the present invention, unless otherwise specified, the numerical range "a~b" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been listed in this document, and "6~22" is just an abbreviation of these numerical combinations.

[0029] The “range” disclosed in the present invention is in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0030] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0031] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the sequence. Preferably, the reaction method herein is carried out sequentially.

[0032] Unless otherwise specified, the professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to the present invention.

[0033] The present invention provides a method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification, comprising the following steps: Prepare polymer dispersed phase and continuous phase solutions 6 respectively; Introducing the polymer dispersed phase and the continuous phase solution 6 into the microfluidic chip 1, the microfluidic chip 1 can be configured as a T-shaped microchannel 12 or a flow focusing microchannel 11; Applying pulsating flow conditions to the continuous phase solution 6 in the T-shaped microchannel 12 or the flow focusing microchannel 11 to generate polymer emulsion droplets, wherein the pulsating flow conditions are achieved by controlling the periodic change of the fluid flow rate; The generated highly viscous and highly elastic polymer emulsion droplets are collected.

[0034] The pulsating flow is applied to the continuous phase solution 6 using a pressure pump 5 .

[0035] The diameter of the T-shaped microchannel 12 or the flow focusing microchannel 11 is 0.1-1 mm to accommodate the formation of polymer emulsion droplets.

[0036] The viscosity of the polymer dispersed phase solution is 2000~10000 centipoise, and the relaxation time is 0.1~1 s.

[0037] The size of the high-viscosity and high-elastic polymer emulsion droplets is controlled by adjusting the pulsation frequency, amplitude and flow rate.

[0038] The frequency of the pulsating flow ranges from 0 to 250 Hz to optimize the uniformity and stability of the droplets.

[0039] The present invention also discloses high-viscosity and high-elastic polymer emulsion droplets prepared by the above-mentioned preparation method. By using pulsating flow technology to generate droplets in a microfluidic chip, the uniformity and stability of the droplets are effectively improved. The application of pulsating flow conditions causes the continuous phase solution to produce periodic changes in the microchannel, and this change helps to overcome the challenge that high-viscosity and high-elasticity polymer solutions are difficult to form stable droplets under conventional flow conditions, thereby ensuring the consistency and reliability of the droplets. The present invention realizes precise control of the droplet size. By adjusting parameters such as pulsation frequency, amplitude and flow rate, the size of the polymer droplets can be accurately adjusted to meet the specific requirements of the droplet size in different application scenarios. This ability of precise control provides strong support for the research and development and production of polymer materials, drug delivery systems, food additives and other fields. In addition, the high-viscosity and high-elastic polymer droplet emulsion prepared by the present invention has a wide range of application potentials in the fields of chemical industry, medicine, food and the like. This droplet emulsion can be used as a raw material or intermediate for preparing composite materials, drug carriers, food additives and the like with specific properties and functions. Its high-quality droplet characteristics and highly controllable preparation process provide strong guarantees for the development and production of related products.

[0040] See also Figure 1 It is a schematic diagram of the composition of the droplet preparation system based on continuous phase velocity pulsation disclosed in the present invention; Figure 2 Schematic diagram of a three-dimensional decomposition of the microfluidic chip of the present invention; as can be seen from the figure, the droplet preparation system based on continuous phase velocity pulsation disclosed in the present invention includes: a pressure pump 5, a syringe pump 4, a pressure sensor 7, a microfluidic chip 1, a collection container 2 and a computer 3; The pressure pump 5 is used to provide velocity pulsation of the continuous phase. The amplitude and frequency of the velocity of the continuous phase are adjusted by the pressure pump 5 to achieve periodic changes in the flow rate of the continuous phase, thereby enhancing the process control of droplet generation; The syringe pump 4 is used to deliver the polymer dispersed phase solution at a constant speed to ensure the stable flow of the dispersed phase in a pulsating flow environment, thereby promoting the formation of uniform droplets; The pressure sensor 7 is used to monitor the pressure changes in the system in real time to ensure that the system operates under the set operating conditions to achieve precise control of the droplet generation process; The microfluidic chip 1 is composed of a capping layer 8, a chip layer 9 and a base layer 10. The capping layer 8 has a two-phase liquid inlet and a liquid outlet connecting the chip layer 9 and the base layer 10. The chip layer 9 is etched with a main structure of a microchannel. The three are tightly bonded by bolts to ensure the sealing of the microchannel. The microchannel main structure of the chip layer 9 is suitable for the T-shaped microchannel 12 or the flow focusing microchannel 11; Furthermore, the size of the microfluidic chip 1 is approximately (100-200) × (50-100) mm, preferably 100 mm × 75 mm; Further, the thickness of the capping layer 8, the chip layer 9 and the base layer 10 are all about 2-4 mm, preferably 2 mm; Further, in the chip layer 9, the length of the T-shaped microchannel 12 or the flow focusing microchannel 11 is 100-200 times the height, the microchannel width is 0.05-1 mm, and the aspect ratio is 0.1-10; The present invention effectively solves the stability and uniformity problems in the generation of high-viscosity and high-elastic polymer emulsion droplets by introducing pulsating flow technology. Compared with traditional technologies, the present invention can not only achieve stable generation and precise control of droplets by adjusting the pulsating frequency and amplitude, thereby improving the consistency of droplet size, but also simplifies system design, reduces manufacturing costs, and is suitable for large-scale industrial applications.

[0041] This method introduces pulsating flow technology to enhance the stability and uniformity of droplet generation of high-viscosity and high-elasticity emulsions, while achieving controllability of droplet generation frequency and size.

[0042] The present invention improves the stability and uniformity of droplets, and through the pulsating flow technology, significantly enhances the stability of high-viscosity and high-elasticity droplet generation and achieves size uniformity.

[0043] The present invention achieves precise control of droplets and can accurately adjust the frequency and size of droplet generation to meet the diverse needs of different application scenarios.

[0044] The present invention simplifies the system structure and reduces the cost: compared with the complex confinement technology and surface acoustic wave technology, the system is simpler in design, has lower manufacturing cost, and is more practical.

[0045] In addition, the present invention can adapt to solutions with various rheological properties, expand the scope of application, and has wide application potential in the fields of chemical industry, medicine, food, etc. It provides an efficient and economical solution for the preparation of high-performance emulsion droplets, showing a wide range of industrial application prospects.

[0046] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] Example 1 A method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification comprises the following steps: Preparation of polymer dispersed phase carbomer gel solution: Carbomer 940 powder and deionized water were mixed at a mass ratio of 1:100, and stirred with an electromagnetic stirrer for 5 h until fully swollen and uniform without agglomeration. NaOH solution was added dropwise for neutralization, and stirred evenly with a stirrer until a gel network was formed in the solution and it was transparent. The pH meter showed that the solution pH was 6. The viscosity of the polymer dispersed phase solution was 10,000 centipoise, and the relaxation time was 1 s.

[0048] Prepare continuous phase solution 6: mix surfactant Span 85 and mineral oil in a mass ratio of 1:20, and use an electromagnetic stirrer to stir for 5 min until fully mixed to obtain continuous phase solution 6.

[0049] A polymer dispersed phase and a continuous phase solution 6 are introduced into a microfluidic chip 1, which is configured as a flow focusing microchannel 11; a pulsating flow condition is applied to the continuous phase solution 6 in the flow focusing microchannel 11 to generate polymer emulsion droplets, and the pulsating flow condition is achieved by controlling the periodic change of the fluid flow rate; the diameter of the flow focusing microchannel 11 is 0.1 mm to accommodate the formation of high-viscosity and high-elasticity polymer emulsion droplets.

[0050] The microfluidic chip 1 is composed of a capping layer 8, a chip layer 9 and a base layer 10. The capping layer 8 has a two-phase liquid inlet and a liquid outlet connecting the chip layer 9 and the base layer 10. The chip layer 9 is etched with a main structure of a microchannel. The three are tightly bonded by bolts to ensure the sealing of the microchannel. The microchannel main structure of the chip layer 9 is suitable for a flow focusing microchannel 11. The size of the microfluidic chip 1 is 150×80 mm. The thickness of the capping layer 8, the chip layer 9 and the base layer 10 are all 3 mm. In the chip layer 9, the length of the flow focusing microchannel 11 is 150 times the height, the width of the microchannel is 0.05 mm, and the aspect ratio is 1.

[0051] The pressure pump 5 is used to adjust the flow rate of the continuous phase solution 6. The pressure pump 5 is controlled by the computer 3 to provide a pulsating speed for the continuous phase solution 6 to achieve a sinusoidal speed pulsation, with a pulsating frequency of 0-250 Hz, a speed amplitude of 12 μL / min, and an initial speed of 12 μL / min. The continuous phase in the microchannel is allowed to pass through the 100 μm wide liquid phase main channel.

[0052] The polymer dispersed phase carbomer gel solution was sucked into a syringe with a capacity of 20 mL. The flow rate was controlled by syringe pump 4 and flowed at a fixed flow rate of 12 μL / min to collect the generated high-viscosity and high-elastic polymer emulsion droplets.

[0053] Figure 3 The images of liquid droplets at different pulsation frequencies disclosed in Example 1 of the present invention are shown in Figure 1; wherein (a) is 0 Hz; (b) is 75 Hz; and (c) is 175 Hz. Specifically, Figure 3 As shown, when f =0 Hz, that is, when there is no pulsation, the flow pattern is parallel flow and no droplets are formed. f =75 Hz, the flow pattern is slug-like flow, producing slug-like polymer droplets. f =175 Hz, the flow pattern is trickle flow, producing spherical polymer droplets.

[0054] Example 2 A method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification comprises the following steps: Preparation of polymer dispersed phase carbomer gel solution: Carbomer 940 powder and deionized water were mixed at a mass ratio of 1:1500, and stirred with an electromagnetic stirrer for 2 h until the solution was fully swollen and uniform without agglomeration. NaOH solution was added dropwise for neutralization, and stirred evenly with a stirrer until a gel network was formed in the solution and the solution was transparent. The pH meter showed that the solution pH was 6. The viscosity of the polymer dispersed phase solution was 2000 centipoise, and the relaxation time was 0.1 s.

[0055] Prepare continuous phase solution 6: mix surfactant Span 85 and mineral oil in a mass ratio of 1:20, and use an electromagnetic stirrer to stir for 5 min until fully mixed to obtain continuous phase solution 6.

[0056] A polymer dispersed phase and a continuous phase solution 6 are introduced into a microfluidic chip 1, which is configured as a T-shaped microchannel 12; a pulsating flow condition is applied to the continuous phase solution 6 in the T-shaped microchannel 12 to generate polymer emulsion droplets, and the pulsating flow condition is achieved by controlling the periodic change of the fluid flow rate; the diameter of the T-shaped microchannel 12 is 0.1 mm to accommodate the formation of high-viscosity and high-elastic polymer emulsion droplets.

[0057] The microfluidic chip 1 is composed of a capping layer 8, a chip layer 9 and a base layer 10. The capping layer 8 has a two-phase liquid inlet and a liquid outlet connecting the chip layer 9 and the base layer 10. The chip layer 9 is etched with a main structure of a microchannel. The three are tightly bonded by bolts to ensure the sealing of the microchannel. The microchannel main structure of the chip layer 9 is suitable for a T-shaped microchannel 12. The size of the microfluidic chip 1 is 200×50 mm. The thickness of the capping layer 8, the chip layer 9 and the base layer 10 are all 2 mm. In the chip layer 9, the length of the T-shaped microchannel 12 is 200 times the height, the width of the microchannel is 0.1 mm, and the aspect ratio is 1.

[0058] The pressure pump 5 is used to adjust the flow rate of the continuous phase solution 6. The pressure pump 5 is controlled by the computer 3 to provide a pulsating speed for the continuous phase solution 6 to achieve a sinusoidal speed pulsation, with a pulsating frequency of 0-250 Hz, a speed amplitude of 12 μL / min, and an initial speed of 12 μL / min. The continuous phase in the microchannel is allowed to pass through the 100 μm wide liquid phase main channel.

[0059] The polymer dispersed phase carbomer gel solution was sucked into a syringe with a capacity of 20 mL. The flow rate was controlled by syringe pump 4 and flowed at a fixed continuous phase flow rate of 12 μL / min to collect the generated high-viscosity and high-elastic polymer emulsion droplets.

[0060] Figure 4 The effect of different pulsation frequencies on droplet volume and droplet generation frequency disclosed in Example 2 of the present invention; wherein (a) is the droplet volume; (b) is the droplet generation frequency. Specifically, Figure 4 As shown in (a), the volume of the polymer droplet can be effectively adjusted by changing the frequency of the velocity pulsation. Figure 4 As shown in (b), within 200 Hz, the droplet generation frequency is synchronized with the pulsation frequency.

[0061] Example 3 A method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification comprises the following steps: Preparation of polymer dispersed phase carbomer gel solution: Carbomer 940 powder and deionized water were mixed at a mass ratio of 1:1500, and stirred with an electromagnetic stirrer for 2 h until the solution was fully swollen and uniform without agglomeration. NaOH solution was added dropwise for neutralization, and stirred evenly with a stirrer until a gel network was formed in the solution and the solution was transparent. The pH meter showed that the solution pH was 6. The viscosity of the polymer dispersed phase solution was 2000 centipoise, and the relaxation time was 0.1 s.

[0062] Prepare continuous phase solution 6: mix surfactant Span 85 and mineral oil in a mass ratio of 1:20, and use an electromagnetic stirrer to stir for 5 min until fully mixed to obtain continuous phase solution 6.

[0063] A polymer dispersed phase and a continuous phase solution 6 are introduced into a microfluidic chip 1, which is configured as a T-shaped microchannel 12; a pulsating flow condition is applied to the continuous phase solution 6 in the T-shaped microchannel 12 to generate polymer emulsion droplets, and the pulsating flow condition is achieved by controlling the periodic change of the fluid flow rate; the diameter of the T-shaped microchannel 12 is 0.1~1 mm to adapt to the formation of high-viscosity and high-elastic polymer emulsion droplets.

[0064] The microfluidic chip 1 is composed of a capping layer 8, a chip layer 9 and a base layer 10. The capping layer 8 has a two-phase liquid inlet and a liquid outlet connecting the chip layer 9 and the base layer 10. The chip layer 9 is etched with a main structure of a microchannel. The three are tightly bonded by bolts to ensure the sealing of the microchannel. The microchannel main structure of the chip layer 9 is suitable for a T-shaped microchannel 12. The size of the microfluidic chip 1 is 100×50 mm. The thickness of the capping layer 8, the chip layer 9 and the base layer 10 are all 3 mm. In the chip layer 9, the length of the T-shaped microchannel 12 is 150 times the height, the width of the microchannel is 0.1 mm, and the aspect ratio is 1.

[0065] The pressure pump 5 is used to adjust the flow rate of the continuous phase solution 6. The pressure pump 5 is controlled by the computer 3 to provide a pulsating speed for the continuous phase solution 6 to achieve a sinusoidal speed pulsation, with a pulsating frequency of 175 Hz, a speed amplitude of 12 μL / min, and an initial speed of 12 μL / min. The continuous phase in the microchannel is allowed to pass through the 100 μm wide liquid phase main channel.

[0066] The polymer dispersed phase carbomer gel solution was sucked into a syringe with a capacity of 20 mL. The flow rate was controlled by the syringe pump 4, and the flow rate varied from 12 μL / min to 24 μL / min. The generated high-viscosity and high-elastic polymer emulsion droplets were collected.

[0067] Figure 5 The effect of different flow rates of the polymer dispersed phase on the volume and generation frequency of droplets disclosed in Example 3 of the present invention; specifically, Figure 5 As shown, the droplet size can be changed at a fixed droplet generation frequency by changing the polymer dispersed phase flow rate.

[0068] Example 4 A method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification comprises the following steps: Preparation of polymer dispersed phase carbomer gel solution: Carbomer 940 powder and deionized water were mixed at a mass ratio of 1:1000, and stirred with an electromagnetic stirrer for 4 hours until the mixture was fully swollen and uniform without agglomeration. NaOH solution was added dropwise for neutralization, and stirred evenly with a stirrer until a gel network was formed in the solution and the solution was transparent. The pH meter showed that the solution pH was 7. The viscosity of the polymer dispersed phase solution was 4000 centipoise, and the relaxation time was 0.4 s.

[0069] Prepare continuous phase solution 6: mix surfactant Span 85 and mineral oil in a mass ratio of 1:20, and use an electromagnetic stirrer to stir for 5 min until fully mixed to obtain continuous phase solution 6.

[0070] A polymer dispersed phase and a continuous phase solution 6 are introduced into a microfluidic chip 1, which is configured as a flow focusing microchannel 11; a pulsating flow condition is applied to the continuous phase solution 6 in the flow focusing microchannel 11 to generate polymer emulsion droplets, and the pulsating flow condition is achieved by controlling the periodic change of the fluid flow rate; the diameter of the flow focusing microchannel 11 is 0.4 mm to accommodate the formation of high-viscosity and high-elasticity polymer emulsion droplets.

[0071] The microfluidic chip 1 is composed of a capping layer 8, a chip layer 9 and a base layer 10. The capping layer 8 has a two-phase liquid inlet and a liquid outlet connecting the chip layer 9 and the base layer 10. The chip layer 9 is etched with a main structure of a microchannel. The three are tightly bonded by bolts to ensure the sealing of the microchannel. The microchannel main structure of the chip layer 9 is suitable for a flow focusing microchannel 11. The size of the microfluidic chip 1 is 100×75mm. The thickness of the capping layer 8, the chip layer 9 and the base layer 10 are all 2 mm. In the chip layer 9, the length of the flow focusing microchannel 11 is 100 times the height, the width of the microchannel is 0.4mm, and the aspect ratio is 0.1.

[0072] The pressure pump 5 is used to adjust the flow rate of the continuous phase solution 6. The pressure pump 5 is controlled by the computer 3 to provide a pulsating speed for the continuous phase solution 6 to achieve a sinusoidal speed pulsation, with a pulsating frequency of 75 Hz, a speed amplitude of 12 μL / min, and an initial speed of 12 μL / min. The continuous phase in the microchannel is allowed to pass through the 1 mm wide liquid phase main channel.

[0073] The polymer dispersed phase carbomer gel solution was sucked into a syringe with a capacity of 20 mL. The flow rate was controlled by syringe pump 4 and flowed at a fixed flow rate of 12 μL / min to collect the generated high-viscosity and high-elastic polymer emulsion droplets.

[0074] Example 5 A method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification comprises the following steps: Preparation of polymer dispersed phase carbomer gel solution: Carbomer 940 powder and deionized water were mixed at a mass ratio of 1:600, and stirred with an electromagnetic stirrer for 5 h until fully swollen and uniform without agglomeration. NaOH solution was added dropwise for neutralization, and stirred evenly with a stirrer until a gel network was formed in the solution and it was transparent. The pH meter showed that the solution pH was 7. The viscosity of the polymer dispersed phase solution was 6000 centipoise, and the relaxation time was 0.6 s.

[0075] Prepare continuous phase solution 6: mix surfactant Span 85 and mineral oil in a mass ratio of 1:20, and use an electromagnetic stirrer to stir for 5 min until fully mixed to obtain continuous phase solution 6.

[0076] A polymer dispersed phase and a continuous phase solution 6 are introduced into a microfluidic chip 1, which is configured as a T-shaped microchannel 12; a pulsating flow condition is applied to the continuous phase solution 6 in the T-shaped microchannel 12 to generate polymer emulsion droplets, and the pulsating flow condition is achieved by controlling the periodic change of the fluid flow rate; the diameter of the T-shaped microchannel 12 is 1 mm to accommodate the formation of high-viscosity and high-elastic polymer emulsion droplets.

[0077] The microfluidic chip 1 is composed of a capping layer 8, a chip layer 9 and a base layer 10. The capping layer 8 has a two-phase liquid inlet and a liquid outlet connecting the chip layer 9 and the base layer 10. The chip layer 9 is etched with a main structure of a microchannel. The three are tightly bonded by bolts to ensure the sealing of the microchannel. The microchannel main structure of the chip layer 9 is suitable for a T-shaped microchannel 12. The size of the microfluidic chip 1 is 200×100mm. The thickness of the capping layer 8, the chip layer 9 and the base layer 10 are all 4 mm. In the chip layer 9, the length of the T-shaped microchannel 12 is 200 times the height, the width of the microchannel is 1 mm, and the aspect ratio is 10.

[0078] The pressure pump 5 is used to adjust the flow rate of the continuous phase solution 6. The pressure pump 5 is controlled by the computer 3 to provide a pulsating speed for the continuous phase solution 6 to achieve a sinusoidal speed pulsation, with a pulsating frequency of 175 Hz, a speed amplitude of 12 μL / min, and an initial speed of 12 μL / min. The continuous phase in the microchannel is allowed to pass through the 1 mm wide liquid phase main channel.

[0079] The polymer dispersed phase carbomer gel solution was sucked into a syringe with a capacity of 20 mL. The flow rate was controlled by syringe pump 4 and flowed at a fixed flow rate of 24 μL / min to collect the generated high-viscosity and high-elastic polymer emulsion droplets.

[0080] In summary, the present invention effectively solves the stability and uniformity problems in the generation of high-viscosity and high-elastic polymer emulsion droplets by introducing pulsating flow technology. Compared with traditional technologies, the present invention has significant advantages: it can not only achieve stable generation and precise control of droplets by adjusting the pulsation frequency and amplitude, thereby improving the consistency of droplet size, but also simplifies system design, reduces manufacturing costs, and is suitable for large-scale industrial applications. In addition, the present invention can adapt to solutions with a variety of rheological properties, expands the scope of application, and has the potential for wide application in the fields of chemical industry, medicine, food, etc. Therefore, the present invention provides an efficient and economical solution for the preparation of high-performance emulsion droplets, showing broad prospects for industrial application.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification, characterized in that: The following steps are involved: Prepare a polymer dispersed phase solution and a continuous phase solution (6) respectively, introduce them into a microfluidic chip (1), and apply a pulsating flow to the continuous phase solution (6) in the microfluidic chip (1), thereby collecting the generated high-viscosity and high-elastic polymer emulsion droplets; The microfluidic chip (1) comprises a capping layer (8), a chip layer (9) and a base layer (10) which are arranged in sequence from top to bottom; the chip layer (9) is provided with a T-shaped microchannel (12) or a flow focusing microchannel (11).

2. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 1, characterized in that: The microfluidic chip (1) is connected to a pressure pump (5) for regulating the periodic change of the flow rate of the continuous phase solution (6); The microfluidic chip (1) is connected to a syringe pump (4) for delivering a polymer dispersed phase solution at a constant speed; The microfluidic chip (1) is connected to a pressure sensor (7) for real-time monitoring of pressure changes in the system; The size of the microfluidic chip (1) is (100-200)×(50-100) mm.

3. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 2, characterized in that: The pulsating flow is achieved by controlling the periodic change of the fluid flow rate; the pulsating flow uses a pressure pump (5) to apply pressure to the continuous phase solution (6); the pulsating flow has a pulsating frequency of 0-250 Hz, a velocity amplitude of 12 μL / min, and an initial velocity of 12 μL / min.

4. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 1, characterized in that: The polymer dispersed phase solution is a carbomer gel solution; the flow rate is controlled at 12-24 μL / min; The carbomer gel solution is prepared by mixing carbomer 940 powder and deionized water in a mass ratio of 1: (100-1500), stirring for 2-5 hours, and then adding a NaOH solution and stirring until a transparent gel network is formed; The continuous phase solution (6) is prepared by stirring the surfactant Span 85 and mineral oil in a mass ratio of 1:20 until they are fully mixed.

5. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 1, characterized in that: The diameter of the T-shaped microchannel (12) or the flow focusing microchannel (11) is 0.1-1 mm.

6. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by utilizing pulsating flow intensification according to claim 1, characterized in that: The length of the T-shaped microchannel (12) or the flow focusing microchannel (11) is 100-200 times of its height, the width is 0.05-1 mm, and the aspect ratio is 0.1-10.

7. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 1, characterized in that: The viscosity of the polymer dispersed phase solution is 2000-10000 centipoise, and the relaxation time is 0.1-1 s.

8. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 1, characterized in that: The size of the high-viscosity and high-elastic polymer emulsion droplets is controlled by adjusting the pulsation frequency, amplitude and flow rate.

9. The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification according to claim 1, characterized in that: The cover layer (8) has a liquid inlet and a liquid outlet communicating with the chip layer (9) and the base layer (10); the thickness of the cover layer (8), the chip layer (9) and the base layer (10) are all 2-4 mm.

10. A highly viscous and highly elastic polymer emulsion droplet, characterized in that: The method for preparing high-viscosity and high-elastic polymer emulsion droplets by using pulsating flow intensification as described in any one of claims 1 to 9 is adopted.

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