W1 / OG / W2 type multiple emulsion based on micro-fluidic chip and preparation method of W1 / OG / W2 type multiple emulsion

Abstract

The invention provides a W1 / OG / W2 type multiple emulsion based on a micro-fluidic chip and a preparation method, and belongs to the technical field of multiple emulsions. The intermediate phase of the multi-emulsion is separated by the oil gel phase OG, so that the exchange of internal and external two-phase substances is thoroughly prevented, the reaction of the internal and external two-phase substances is avoided, the substance compatibility is enhanced, and meanwhile, the aqueous phase thickener is added into the hydrogel phase W2, so that the viscosity of the hydrogel phase W2 is increased, the aggregation of liquid drops is delayed, and the stability of the emulsion is improved. According to the method, the active encapsulant can be encapsulated in the microdroplet to form a protective layer, so that the contact with air and the external environment is reduced, the encapsulant in the water-in-oil phase W1 / O is effectively prevented from being oxidized, the stability and the slow-release effect of the encapsulant are improved, and the storage life is prolonged. The multi-emulsion has wide applicability and can be widely applied to the fields of food, medicines, health care products and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of multiple emulsions and relates to a W1 / OG / W2 type multiple emulsion based on a microfluidic chip and a preparation method thereof. Background Art

[0002] Multiple emulsions, also known as composite emulsions or emulsions for short, are multi-layer emulsions formed by dispersing an emulsion in another continuous phase. Multiple emulsions are generally highly dispersed multiphase systems with different particle sizes, mainly including water-in-oil-in-water (W / O / W) emulsions and oil-in-water-in-oil (O / W / O) emulsions. Structurally, multiple emulsions have a unique multi-compartment structure of "two membranes and three phases", which can dissolve some substances with different properties in different phases, and play a variety of functions such as isolation, protection, controlled release, and targeted release. Therefore, they have broad application value in the fields of medicine, food, and cosmetics.

[0003] There are large phase interfaces and high interfacial energy between the phases of multiple emulsions. Multiple emulsions are thermodynamically unstable systems with inherent tendencies of aggregation, flocculation, and stratification, which greatly limits the widespread application of multiple emulsions. In order to improve the stability of multiple emulsions, thickeners or osmotically active substances are usually added to the water phase to increase the viscosity of the water phase or to make the emulsified particles repel each other in the oil phase to delay the aggregation between droplets. Although the above methods can improve the stability of multiple emulsions, the stability of multiple emulsions is still poor, resulting in the components in the multiple emulsions that are extremely sensitive to light, temperature changes, and moisture being easily degraded and oxidized, which ultimately leads to a decrease in their activity and purity. Summary of the invention

[0004] The purpose of the present invention is to provide a W1 / OG / W2 type multiple emulsion based on a microfluidic chip and a preparation method thereof, so as to solve the problem of poor stability of existing multiple emulsions.

[0005] To achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present application provides a W1 / OG / W2 type multiple emulsion based on a microfluidic chip, wherein the raw materials for preparing the multiple emulsion include: an oil-in-water phase W1 / O, an oil gel phase OG, and a hydrogel phase W2. Among them, the raw materials for preparing the oil-in-water phase W1 / O include oil-in-water grease, a lipophilic emulsifier, a moisturizer, a preservative, an osmoactive substance, an encapsulant, and a solvent. The raw materials for preparing the oil gel phase OG include oil gel grease, an oil phase thickener, and a cationic surfactant. The raw materials for preparing the hydrogel phase W2 include a water phase thickener, a moisturizer, a preservative, and a pH adjuster. The following are respectively described in detail.

[0006] 1. Raw materials for the preparation of water-in-oil phase W1 / O The water-in-oil grease includes at least one of hydrocarbons, triglycerides, esters, fatty alcohols, fatty acids and dimethylsiloxane, specifically including isononyl isononanoate, ethylhexyl palmitate, caprylic / capric triglyceride, dicaprylyl carbonate, polydimethylsiloxane, cyclopentasiloxane, isooctane, isododecane, mineral oil, petrolatum, synthetic squalane, etc.

[0007] The lipophilic emulsifier includes at least one of glyceryl monostearate, sorbitan palmitate, sorbitan stearate, sorbitan oleate, sorbitan sesquioleate, sorbitan trioleate, polyoxyethylene stearyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene beeswax, polyglyceryl-4 isostearate and polyglyceryl ricinoleate.

[0008] The moisturizer includes at least one of fatty alcohols, fatty acids and their salts, and fatty acid esters. The fatty alcohols are selected from at least one of glycerol, sorbitol, mannitol, polyethylene glycol, xylitol, cetyl alcohol, and lanolin alcohol. The fatty acid esters are selected from at least one of hexyl laurate, isopropyl myristate, isobutyl myristate, isopropyl palmitate, and isobutyl palmitate.

[0009] The preservative includes at least one of parabens, alcohols, and organic acids and their salts. Among them, parabens are selected from at least one of methyl, ethyl, propyl, and butyl. Alcohols are selected from phenoxyethanol and / or benzyl alcohol. Organic acids and their salts are selected from at least one of benzoic acid, sodium benzoate, sorbic acid, and potassium sorbate.

[0010] The osmotically active substance includes at least one of sodium chloride, potassium chloride, magnesium sulfate, and sodium sulfate.

[0011] The encapsulated material refers to a water-soluble substance sealed and preserved by the oil gel, including at least one of carotenoids, flavonoids, oils, saponins, terpenoid compounds, flavors, pigments and essential oils, specifically including ginsenosides, stigmasterol, carotene, campesterol, glycosyl diglycerides, nicotinamide mononucleotide, ascorbyl palmitate, benzophenone-4, carotenoids, quercetin, glutathione, isoflavones, tocopherols and tocotrienols, ascorbic acid-2-phosphate, anthocyanins, etc.

[0012] The solvent includes at least one of distilled water, deionized water, reverse osmosis water, sea water, well water, animal extracts, and plant extracts.

[0013] 2. Raw materials for the preparation of oil gel phase OG The oleogel oil comprises at least one of vegetable oil and synthetic oil. The vegetable oil is selected from at least one of olive oil, coconut oil, palm oil, castor oil, almond oil, soybean oil, sea buckthorn seed oil, cocoa butter, safflower oil, avocado oil, almond oil, wheat germ oil, sesame oil, shea butter, grape seed oil, rosehip oil, cactus seed oil, macadamia nut oil, hazelnut oil, sweet almond oil and camellia oil.

[0014] The oil phase thickener comprises at least one of amino dimethicone, glyceryl fatty acid ester, dextrin palmitate, and hydrogenated castor oil / capric acid copolymer.

[0015] The cationic surfactant includes at least one of alkyl quaternary ammonium salts, acyloxy quaternary ammonium salts and dimethylamine cationic conditioning agents. Among them, the alkyl quaternary ammonium salt is selected from at least one of lauryl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride and behenyl trimethyl ammonium chloride. The acyloxy quaternary ammonium salt is selected from at least one of behenyl acyloxy PG-trimethyl ammonium chloride and di-fatty alkyl ester hydroxyethyl methyl sulfate methylamine. The dimethylamine cationic conditioning agent is selected from at least one of stearamidopropyl dimethylamine and behenamidopropyl dimethylamine.

[0016] 3. Raw materials for preparation of hydrogel phase W2 The aqueous phase thickener includes at least one of natural and modified natural polymers, organic synthetic polymers and inorganic polymers. Among them, the natural and modified natural polymers are selected from at least one of xanthan gum, gum arabic, carrageenan, pectin, starch dextrin, maltodextrin, starch derivatives, cellulose derivatives, guar gum and its derivatives, alginates and esters, and locust bean gum. The organic synthetic polymer is selected from at least one of acrylic resin polymers, acrylamide polymers, hydrogenated polyisobutylene, polyvinyl pyrrolidone, acrylic acid, and methacrylic acid polymers. Among them, the acrylic resin is carbomer, which is a high molecular polymer of acrylic acid bonded allyl sucrose or pentaerythritol allyl ether. In the present application, carbomer can be a polymer sold under the trade names Carbopol934, Carbopol940, Carbopol941, Carbopol980, and Carbopol981. The inorganic polymer is selected from at least one of hydrated silica gel, synthetic sodium magnesium silicate, and bentonite.

[0017] The moisturizer includes at least one of fatty alcohols, fatty acids and their salts, and fatty acid esters. The fatty alcohols are selected from at least one of glycerol, sorbitol, mannitol, polyethylene glycol, xylitol, cetyl alcohol, and lanolin alcohol. The fatty acid esters are selected from at least one of hexyl laurate, isopropyl myristate, isobutyl myristate, isopropyl palmitate, and isobutyl palmitate.

[0018] The preservative includes at least one of parabens, alcohols, and organic acids and their salts. Among them, parabens are selected from at least one of methyl, ethyl, propyl, and butyl. Alcohols are selected from phenoxyethanol and / or benzyl alcohol. Organic acids and their salts are selected from at least one of benzoic acid, sodium benzoate, sorbic acid, and potassium sorbate.

[0019] The pH adjuster includes at least one of sodium hydroxide, potassium hydroxide, sodium dihydrogen phosphate, potassium dihydrogen phosphate, arginine and triethanolamine.

[0020] In a second aspect, the present application also provides a method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip, the method comprising: S01: dissolve the encapsulated material in water, stir evenly to form an inner water phase W1; dissolve the lipophilic emulsifier in the water-in-oil grease, stir evenly to form an oil phase O; drip the inner water phase W1 into the oil phase O while stirring, and homogenize at high speed to obtain the water-in-oil phase W1 / O.

[0021] The water-soluble encapsulate is placed in water and stirred to dissolve to form an inner water phase W1. The lipophilic emulsifier is dissolved in the water-in-oil grease and stirred evenly to form an oil phase O. The mass fraction of the lipophilic emulsifier in the oil phase O is 0.1-10%, and preferably, the mass fraction of the lipophilic emulsifier in the oil phase O is 1-6%.

[0022] According to the dropping speed of 5-50ml / min and the stirring speed of 100-1000rpm, the inner water phase W1 is added to the oil phase O while stirring. After the dropping is completed, stirring is continued for 2-5min. After the stirring is completed, high-speed shear homogenization is performed at a speed of 1000-9000rpm for 1-3min to obtain an oil-in-water phase W1 / O. Among them, the mass ratio of the inner water phase W1 to the oil phase O is 1:1-1:4. Preferably, the stirring speed is 300-700rpm and the high-speed shear homogenization speed is 3000-6000rpm.

[0023] S02: Mix the oil gel grease and the oil phase thickener in a mass ratio of 1:5-1:12, and stir evenly with a magnetic stirrer to form a transparent oil gel phase OG. Preferably, the mass ratio of the oil gel grease and the oil phase thickener is 1:8-1:10.

[0024] S03: Mix the aqueous phase thickener, moisturizer and preservative, heat and dissolve them, adjust the pH to 2-10 with a pH adjuster, and then cool them to form a hydrogel phase W2. The mass percentage of the aqueous phase thickener is 0.01-10%, and the mass percentage of the moisturizer is 1-20%. Preferably, the mass percentage of the aqueous phase thickener is 0.05-5%, the mass percentage of the moisturizer is 5-10%, and the pH of the hydrogel phase W2 is 4-8; more preferably, the mass percentage of the aqueous phase thickener is 0.15-2%, and the pH of the hydrogel phase W2 is 5-7.

[0025] S04: The water-in-oil phase W1 / O and the oil gel phase OG are fully mixed to obtain the water-in-oil phase W1 / OG, wherein the mass ratio of the water-in-oil phase W1 / O to the oil gel phase OG is 1:2-1:10, and preferably, the mass ratio is 1:4-1:8.

[0026] S05: The water-in-oil gel phase W1 / OG and the hydrogel phase W2 are mixed through a microfluidic chip to obtain a W1 / OG / W2 type multiple emulsion.

[0027] The oil-gel-water phase W1 / OG and the hydrogel phase W2 were introduced into the PDMS microfluidic chip through silicone hoses at flow rates of 200 ml / h and 50 ml / h, respectively, so that the oil-gel-water phase W1 / OG was evenly dispersed in the hydrogel phase W2, and the mixture was collected through the collection port to obtain a W1 / OG / W2 type multiple emulsion.

[0028] The present invention has the following beneficial effects: (1) The middle phase is separated by the oil gel phase OG, which completely prevents the exchange of substances between the inner and outer phases and avoids the reaction of substances between the inner and outer phases, such as the Schiff base reaction and acid-base neutralization reaction of peptides and sugars, thereby enhancing the compatibility of the substances.

[0029] (2) Adding a water phase thickener to the hydrogel phase W2 is beneficial to increasing the viscosity of the hydrogel phase W2, delaying the aggregation between droplets, and thus improving the stability of the emulsion.

[0030] (3) Adding osmotically active substances to the internal phase can make the emulsified particles charged, causing the emulsified particles to repel each other in the oil phase and be less likely to aggregate, thereby improving the stability of the emulsion.

[0031] (4) Microfluidic technology is combined in the preparation process of multiple emulsions, so that the active encapsulated substances are encapsulated in microdroplets to form a protective layer, which reduces contact with air and the external environment, effectively prevents the encapsulated substances in the oil-in-water phase W1 / O from being oxidized, improves the stability and sustained release effect of the encapsulated substances, and prolongs the shelf life.

[0032] (5) Microfluidic technology is combined in the preparation process of multiple emulsions, which can form multiple emulsions with uniform particle size, and the emulsions are stable and do not break.

[0033] (6) The multiple emulsion has wide applicability and can be widely used in the fields of food, medicine, health care products, etc. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further explained and illustrated by means of specific embodiments below.

[0035] Examples 1-4 and Comparative Example 1 of the present application respectively provide a W1 / OG / W2 type multiple emulsion based on a microfluidic chip. The raw materials for preparing the multiple emulsion and the addition amount are shown in Table 1, wherein the addition amount is measured in g.

[0036] Table 1: Preparation materials and addition amounts of Examples 1-4 and Comparative Example 1 The preparation methods of the multiple emulsions in the above Examples 1-4 and Comparative Example 1 are all: S01: The raw materials No. 1-3 are heated and dissolved at 85°C to form an oil phase O. The raw materials No. 4-8 are heated and dissolved at 85°C to form an inner water phase W1. At a stirring speed of 500 rpm, the inner water phase W1 is dripped into the oil phase O at a dripping speed of 20 ml / min while stirring. After the dripping is completed, stirring is continued for 4 minutes. After the stirring is completed, high-speed shearing and homogenization is performed at a speed of 5000 rpm for 1-3 minutes to obtain an oil-in-water phase W1 / O.

[0037] S02: The raw materials No. 9 to 12 are stirred evenly using a magnetic stirrer to form a transparent oil gel phase OG.

[0038] S03: The raw materials No. 13-17 are heated and dissolved at 85° C., and the pH value is adjusted to 7 using the raw material No. 18 to form a hydrogel phase W2.

[0039] S04: The water-in-oil phase W1 / O and the oil gel phase OG are fully mixed to obtain the water-in-oil gel phase W1 / OG.

[0040] S05: The oil-gel-water phase W1 / OG and the hydrogel phase W2 are introduced into the PDMS microfluidic chip through a silicone hose at a flow rate of 200 ml / h and 50 ml / h, respectively, so that the oil-gel-water phase W1 / OG is evenly dispersed in the hydrogel phase W2, and the mixture is collected through a collection port to obtain a W1 / OG / W2 type multiple emulsion.

[0041] The W1 / OG / W2 type multiple emulsions prepared in Examples 1-4 and Comparative Example 1 were subjected to freeze-thaw experiments, centrifugation experiments, and encapsulation stability tests to verify the stability of the W1 / OG / W2 type multiple emulsions prepared in the Examples of the present application. The specific contents are as follows: 1. Freeze-thaw experiment The W1 / OG / W2 type multiple emulsions prepared in Examples 1-4 and Comparative Example 1 were respectively placed in cylindrical plastic containers or glass containers, covered with sealing covers, placed in a low temperature box at -5±2°C, taken out after 18 hours, and then placed at 23±2°C for 6 hours. After repeatedly placing at low temperature and room temperature for three times, the container was opened, stirred with a glass rod, and the sample was observed for abnormal phenomena such as lumps and agglomeration. Specifically, the sample was coated on a glass plate into a uniform thin layer with the help of a glass rod, and then the presence of flocculants was observed, and the records were as shown in Table 2.

[0042] Table 2: Freeze-thaw experiment results As can be seen from Table 1, after being repeatedly placed at low temperature and room temperature for three times, the multiple emulsions in Examples 1-3 all existed stably without abnormal phenomena such as lumps and coagulation; the multiple emulsion in Comparative Example 1 flocculated. This indicates that in the preparation process of the multiple emulsion, the W1 / OG / W2 type multiple emulsion prepared by adding a thickener and an appropriate amount of cationic surfactant to the oil gel phase OG and the hydrogel phase W2 can be stably stored in repeated low temperature and room temperature environments.

[0043] 2. Centrifugation experiment The W1 / OG / W2 multiple emulsions prepared in Examples 1-4 and Comparative Example 1 were placed in centrifuge tubes respectively. After balancing for 10 minutes, the centrifuge tubes were placed in a centrifuge and centrifuged for 20 minutes at different speeds. Whether oil floating occurred was observed and recorded as shown in Table 3.

[0044] Table 3: Centrifugation test results As can be seen from Table 3, when the rotation speed is a low rotation speed of 100 rpm, the multiple emulsions in Examples 1-4 and Comparative Example 1 all remain stable. When the rotation speed is a medium rotation speed of 500 rpm, the multiple emulsions in Examples 2-4 all remain stable, and the multiple emulsions in Example 1 and Comparative Example 1 exhibit oil floating. When the rotation speed is a high rotation speed of 1000 rpm, the multiple emulsion in Example 3 remains stable, and the multiple emulsions in Examples 1, 2, 4 and Comparative Example 1 all exhibit oil floating. This indicates that in the process of preparing the multiple emulsions, the W1 / OG / W2 type multiple emulsion prepared by adding two lipophilic emulsifiers of different properties to the oil-in-water phase W1 / O and adding a thickener to the oil gel phase OG has stable properties.

[0045] 3. Encapsulation stability test The W1 / OG / W2 type multiple emulsions prepared in Examples 3 and 4 and Comparative Example 1 were respectively subjected to long-term illumination, and the fading of the multiple emulsions was observed under different illumination times, and the results were recorded in Table 4.

[0046] Table 4: Encapsulation stability test results As can be seen from Table 4, when the illumination time is 1 day and 14 days respectively, the multiple emulsions in Examples 3, 4 and Comparative Example 1 did not fade. When the illumination time is 28 days, the multiple emulsions in Examples 3 and 4 did not fade, and the multiple emulsion in Comparative Example 1 faded. When the illumination time is 42 days, the multiple emulsion in Example 3 did not fade, and the multiple emulsions in Example 4 and Comparative Example 1 faded. When the illumination time is 56 days, the multiple emulsion in Example 3 did not fade, and the multiple emulsions in Example 4 and Comparative Example 1 faded. This shows that in the preparation process of the multiple emulsions, a thickener is added to the oil gel phase OG to form a protective layer, which reduces contact with air and the external environment, effectively avoids oxidation of the encapsulated material in the oil-in-water phase W1 / O, and improves the stability of the encapsulated material.

[0047] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A W1 / OG / W2 type multiple emulsion based on a microfluidic chip, characterized in that: The raw materials for preparing the multiple emulsion include: a water-in-oil phase W1 / O, an oil gel phase OG and a hydrogel phase W2; wherein, The raw materials for preparing the water-in-oil phase W1 / O include water-in-oil grease, lipophilic emulsifier, moisturizer, preservative, osmotic active substance, encapsulate and solvent; The raw materials for preparing the oil gel phase OG include oil gel grease, oil phase thickener and cationic surfactant; The raw materials for preparing the hydrogel phase W2 include a water phase thickener, a moisturizer, a preservative and a pH adjuster.

2. The W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 1, characterized in that: The water-in-oil grease includes at least one of hydrocarbons, triglycerides, esters, fatty alcohols, fatty acids and dimethylsiloxane; the lipophilic emulsifier includes at least one of monostearate glyceryl, sorbitan palmitate, sorbitan stearate, sorbitan oleate, sorbitan sesquioleate, sorbitan trioleate, polyoxyethylene stearyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene beeswax, polyglyceryl-4 isostearate and polyglyceryl ricinoleate; the moisturizer includes fatty alcohol The preservative comprises at least one of parabens, alcohols and organic acids and their salts; the osmotic active substance comprises at least one of sodium chloride, potassium chloride, magnesium sulfate and sodium sulfate; the encapsulate comprises at least one of carotenoids, flavonoids, oils, saponins, terpenoid compounds, flavors, pigments and essential oils; the solvent comprises at least one of distilled water, deionized water, reverse osmosis water, sea water, well water, animal extracts and plant extracts.

3. The W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 1, characterized in that: The oil gel oil includes at least one of vegetable oil and synthetic oil; the oil phase thickener includes at least one of amino-terminated polydimethylsiloxane, glycerol fatty acid ester, dextrin palmitate, and hydrogenated castor oil / capric acid copolymer; the cationic surfactant includes at least one of alkyl quaternary ammonium salt, ester quaternary ammonium salt and dimethylamine cationic conditioning agent.

4. The W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 1, characterized in that: The aqueous phase thickener includes at least one of natural and modified natural polymers, organic synthetic polymers and inorganic polymers; the humectant includes at least one of fatty alcohols, fatty acids and their salts and fatty acid esters; the preservative includes at least one of parabens, alcohols and organic acids and their salts; the pH adjuster includes at least one of sodium hydroxide, potassium hydroxide, sodium dihydrogen phosphate, potassium dihydrogen phosphate, arginine and triethanolamine.

5. A method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip, characterized in that: include: Dissolve the encapsulated material in water and stir evenly to form an inner water phase W1; Dissolve the lipophilic emulsifier in the water-in-oil grease and stir evenly to form an oil phase O; The inner water phase W1 is dripped into the oil phase O while stirring, and high-speed shearing and homogenization are performed to obtain a water-in-oil phase W1 / O; Mixing the oil gel grease and the oil phase thickener evenly to form an oil gel phase OG; The aqueous phase thickener, moisturizer and preservative are mixed and heated to dissolve, the pH is adjusted to 2-10 with a pH adjuster, and then cooled to form a hydrogel phase W2; The water-in-oil phase W1 / O and the oil gel phase OG are uniformly mixed to obtain the water-in-oil gel phase W1 / OG; The water-in-oil gel phase W1 / OG and the hydrogel phase W2 are mixed through a microfluidic chip to obtain a W1 / OG / W2 type multiple emulsion.

6. The method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 5, characterized in that: The mass fraction of the lipophilic emulsifier in the oil phase O is 0.1-10%; the mass ratio of the internal water phase W1 to the oil phase O is 1:1-1:

4.

7. The method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 5, characterized in that: The dripping speed of the internal water phase W1 is 5-50 ml / min, the stirring speed is 100-1000 rpm, and the high-speed shearing homogenization speed is 1000-9000 rpm.

8. The method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 5, characterized in that: The mass ratio of the oil gel grease to the oil phase thickener is 1:5-1:

12.

9. The method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 5, characterized in that: The mass percentages of the water phase thickener and the moisturizing agent are 0.01-10% and 1-20% respectively.

10. The method for preparing a W1 / OG / W2 type multiple emulsion based on a microfluidic chip according to claim 5, characterized in that: In the microfluidic chip, the flow rate of the water-in-oil gel phase W1 / OG is 200 ml / h, and the flow rate of the hydrogel phase W2 is 50 ml / h.

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