WO2020042266A1

WO2020042266A1 - Double emulsion glass capillary microfluidic chip, and phase change microcapsule prepared therefrom

Info

Publication number: WO2020042266A1
Application number: PCT/CN2018/107925
Authority: WO
Inventors: 陈颖; 李俊; 贾莉斯; 李亦昂
Original assignee: 广东工业大学
Priority date: 2018-08-31
Filing date: 2018-09-27
Publication date: 2020-03-05
Also published as: CN109201130B; CN109201130A

Abstract

A double emulsion glass capillary microfluidic chip, and a phase change microcapsule prepared therefrom. A multiple emulsion droplet microfluidic chip is used for preparing a phase change material microemulsion, which significantly improves the controllability of the prepared capsule, and the practical value thereof. A high precision injection pump (1) is used for precisely controlling the emulsion process of a core material and a wall material in the microfluidic chip to obtain a phase change material microemulsion having good monodispersity and high sphericity. An ultraviolet light is used for curing the wall material, which reduces the preparation time and cost, and improves the controllability of the wall material. The preparation process has advantages that the device is simple, the operation is simple, the utilization rate of a raw material is high, it is easy to control the particle size, the sphericity, the thickness of a shell, and the size of the core material, it is noise-free, no hazardous waste is produced, the energy consumption is low and the like, and is suitable for scientific research and popularization and application of industrially producing different phase change microcapsules.

Description

Double emulsified glass capillary microfluidic chip and phase change microcapsule made therefrom

Technical field

The invention belongs to the technical field of preparation of phase-change microcapsule materials, and particularly relates to a double-emulsion glass capillary microfluidic chip and a phase-change microcapsule made by the same.

Background technique

In recent years, thermal energy storage technology (TES) has become an important new energy-saving technology, which has played a very significant role in improving energy efficiency, and has become a very active research hotspot in the field of energy science. Phase change materials are a type of energy storage materials that can store and release a large amount of latent heat. They are widely used in heat storage and temperature control. However, because phase change materials are generally corrosive, have low heat exchange efficiency, and solid-liquid transformation, Limits the use of phase change materials. Microencapsulated phase change material is a new technology for preparing phase change microcapsules by applying capsule technology to phase change materials. Phase change microcapsules usually consist of two parts: the core of the phase change material and the shell of the polymer material. The shell of the polymer material completely encapsulates the phase change material inside to form a capsule structure with a particle size of micrometers or even nanometers. Phase change microcapsules have advantages that pure phase change materials do not have, such as a larger specific surface area and a larger thermal conductivity, which isolates the core material from contact with the external environment, improves the stability of the phase change material, and prevents the core material from leaking easily. Due to these excellent characteristics, phase change microcapsules have been widely used in the fields of building energy saving, electronic heat dissipation, clothing textile, heat transfer medium, military, agriculture and other fields.

At present, the commonly used methods for preparing phase change microcapsules include physical and chemical methods and physical chemical methods, such as interfacial polymerization method, double emulsion method, gel sol method, suspension method, in-situ polymerization method, and the like. These traditional methods have the advantages of mature technology and large output. Some methods have been applied to the mass production of capsules in industry. However, most of these methods use mechanical methods such as mechanical stirring and spraying to emulsify phase change materials, resulting in capsules with the disadvantages of difficult to control particle size, large polydispersity, low coverage, and easy breakage. Insufficient control of the cystic nature and the capsule wall of the phase change microcapsules during the preparation process makes the use of phase change microcapsules limited.

In recent years, the development of microfluidic technology in the field of emulsion preparation has gradually matured. Using microfluidic chips, it has been possible to prepare monodispersed droplets such as monolayers, bilayers and even multilayers. By integrating other chemical and physical methods, various materials can be synthesized and prepared in microfluidic chips. The dual droplet preparation technology is a new technique for preparing stable dual droplets by controlling the interaction of the three-phase fluid. The structure and size of the dual droplets can be changed by changing the flow rate of the three-phase fluid in the microchip. Precise control. At present, there are few reports on the use of dual-droplet preparation technology combined with UV curing to prepare phase change microcapsules with controllable core and wall size.

Summary of the Invention

In order to overcome the defects of uncontrollable particle size, large particle size distribution, and uncontrollable capsule core and capsule wall in the prior art, the primary object of the present invention is to provide a double emulsified glass capillary microfluidic chip. The shell thickness and core material size of the prepared phase change microcapsules were controlled.

Another object of the present invention is to provide a method for preparing phase change microcapsules by using the above double-emulsified glass capillary microfluidic chip.

Another object of the present invention is to provide a phase change microcapsule prepared by the above method.

The object of the present invention is achieved by the following technical solutions:

A double emulsified glass capillary microfluidic chip, comprising a large glass capillary, a small glass capillary, a large-nosed glass capillary, a small-nosed glass capillary, two conical centrifuge tubes, and a glass slide abutment;

Only the exit end of the large-nosed glass capillary and the small-nosed glass capillary are pointed. The small-nosed glass capillary is coaxially inserted into the inside of the large-nosed glass capillary, and the two-nosed nozzles are located on the same side. The distance is 10-500 microns; the large-nosed glass capillary is inserted in the direction of the pointed glass capillary from the entrance of the large glass capillary, the small glass capillary is inserted from the large glass capillary exit, and the pointed tip of the large-nosed glass capillary extends into the small glass capillary. 10-100 microns; large glass capillary placed on a glass slide abutment;

The two conical centrifuge tubes are inverted at the entrances of the large-tip glass capillary and the large-capillary glass capillary, respectively, and are used between the conical centrifuge tube, the large-tip glass capillary, the small-tip glass capillary and the slide base. The sealant forms a first closed liquid storage tank, and the sealant forms a second closed liquid storage tank between the conical centrifuge tube, the large glass capillary tube, the large-nosed glass capillary tube, and the glass slide base;

The inlets of the small-nosed glass capillary and the two conical centrifuge tubes are connected to three syringe pumps through Teflon catheters, respectively.

The outer diameter of the large glass capillary is 500-1000 microns, and the inner diameter is 400-900 microns; the outer diameter of the small glass capillary and the large-nosed glass capillary is 300-800 microns, and the inner diameter is 200-700 microns; the small-tip glass The outer diameter of the capillary is 100-600 microns and the inner diameter is 50-500 microns; the ratio of the internal diameter of the large-nosed glass capillary to the internal diameter of the nozzle is greater than 1 and less than 10; The ratio is greater than 1 and less than 10.

The sealant is epoxy resin.

A method for preparing a phase-change microcapsule by using the above double-emulsified glass capillary microfluidic chip includes the following steps:

(1) Disperse phase 1, dispersed phase 2 and continuous phase are pushed into the Teflon catheter from the syringe pump and passed into the double emulsified glass capillary microfluidic chip. Among them, dispersed phase 1 is introduced into the microfluid from the small-tip glass capillary. Control chip, dispersed phase 2 is passed from the first closed liquid storage tank into the microfluidic chip, and continuous phase is passed from the second closed liquid storage tank into the microfluidic chip;

(2) using an ultraviolet light source to irradiate the end of the small glass capillary of the microfluidic chip, and collect the cured capsule at the outlet of the small glass capillary;

(3) The capsules obtained in step (3) are filtered, repeatedly washed with deionized water and anhydrous ethanol, and dried at room temperature to obtain phase change microcapsules with controllable thickness and capsule core.

The dispersed phase 1 in step (1) is a phase change material; the dispersed phase 2 is a photocuring agent monomer, a mixture of a surfactant 1 and a photoinitiator, and a mass fraction of the surfactant 1 is 0-3%. The mass fraction of the initiator is 1-2%; the continuous phase is a mixture of surfactant 2 and water, and the mass fraction of the surfactant 2 is 1-10%.

The phase change material is an alkane or an alkane halide; the photocuring agent monomer is an unsaturated polyester resin; the surfactant 1 is an oil-soluble ionic or non-ionic surfactant; the photoinitiator is Darocur 1173; the surfactant 2 is a water-soluble ionic or non-ionic surfactant.

The phase change material is heptadecane; the photocuring agent monomer is 1,6-hexanediol diacrylate (HDDA); the surfactant 1 is Span-80 (Span-80); the The surfactant 2 is polyvinyl alcohol.

The syringe pump in step (1) separately controls the three-phase flow rate into the microfluidic chip, wherein the flow rate of the dispersed phase 1 is 2-30 μl / min, and the flow rate of the dispersed phase 2 is 5-50 μl / min. The continuous phase The flow rate is 50-500 μl / min.

The wavelength of the ultraviolet light of the ultraviolet lamp light source in step (2) is 360 nm, and the radiation intensity of the end of the small glass capillary is greater than 100 mW / cm ² .

A phase change microcapsule prepared according to the above method. The phase change microcapsule is composed of a polyester resin as a wall material and an alkane or alkane halide as a core material. The core size of the phase change microcapsule is in the range of 30-500 μm. Internally controllable, its capsule wall thickness can be controlled within the range of 1-200 μm, the overall capsule size range is 30-600 μm, the phase change microcapsule particle size deviation is less than 4 μm, the phase change microcapsules with the target preparation size have a proportion greater than 70%, and the core The material content is 50-90%.

The principle of the invention is:

Multi-emulsion droplet microfluidics and UV curing technology are used to emulsify and encapsulate the phase change material in the microfluidic chip. By adjusting the three-phase flow rate ratio in the microfluidic chip to control the size of the capsule, the size of the capsule core, and the thickness of the capsule wall, the double droplets generated by ultraviolet light irradiation make the capsule wall material solidify and finally encapsulate the capsule core to form a phase change microcapsule. The present invention uses multiple emulsified droplet microfluidic chips to prepare phase-change material microemulsions, which greatly enhances the controllability of the prepared capsules and increases the practical value of the capsules. The core material is precisely controlled using a high-precision syringe pump The emulsification process of the wall material and the microfluidic chip yields a phase change material microemulsion with good monodispersity and high sphericity. The use of ultraviolet light to cure the wall material reduces the preparation time and cost, and also improves the controllability of the wall material.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The invention can simply and effectively control the core size and wall thickness of phase change microcapsules, so that the mechanical properties and energy storage performance of the prepared capsules can be effectively controlled, and phase change microcapsule materials suitable for various use requirements can be obtained. At the same time, the size of the phase change microcapsules can be controlled, and the particle size can be reduced. The preparation process has the advantages of simple equipment, easy operation, high raw material utilization rate, easy control of product particle size, shell thickness and core material size, no noise, no harmful waste, low energy consumption, etc., suitable for scientific research and industrial production. Promotion and application of phase change microcapsules.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a system for preparing phase change microcapsules using a double-emulsion glass capillary microfluidic chip, where 1 is a syringe pump; 2 is a Teflon catheter; 3 is a conical centrifuge tube; 4 is an ultraviolet light source; 5 is a large glass Capillaries; 6 is a small glass capillary; 7 is a glass slide abutment; 8 is a large-nosed glass capillary; 9 is a small-nosed glass capillary.

detailed description

The present invention is described in further detail below with reference to the examples, but the embodiments of the present invention are not limited thereto.

The structure of the double-emulsion glass capillary microfluidic chip used in the following examples is shown in FIG. 1, which includes a large glass capillary 5, a small glass capillary 6, a large pointed glass capillary 8, a small pointed glass capillary 9, and two conical centrifuges. Tube 3 and slide abutment 7;

Only the exit end of the large-nosed glass capillary 8 and the small-nosed glass capillary 9 is a pointed mouth. The small-nosed glass capillary 9 is coaxially inserted into the inside of the large-nosed glass capillary 8 and both of the pointed noses are located on the same side The distance between the tips of the two is 10-500 microns; the large-nosed glass capillary 8 is inserted in the direction of the nozzle from the entrance of the large glass capillary 5; the small glass capillary 6 is inserted from the large-glass capillary 5 outlet; The pointed mouth extends into the small glass capillary 6 to 10-100 microns; the large glass capillary 5 is placed on a glass slide base;

The two conical centrifuge tubes 3 are inverted at the entrance of the large-tip glass capillary 8 and the large-capillary glass capillary 5, respectively; the conical centrifuge tube 3, the large-tip glass capillary 8, the small-tip glass capillary 9 and the glass carrier A sealant is used to form a first closed liquid storage tank between the abutment 7 and a sealant is used to form a second seal between the conical centrifuge tube 3, the large glass capillary 5, the large-nosed glass capillary 8 and the glass slide abutment 7. Liquid storage tank

The inlets of the small-nosed glass capillary 9 and the two conical centrifuge tubes 3 are connected to three injection pumps 1 through Teflon catheters 2 respectively.

The outer diameter of the large glass capillary is 500-1000 microns, and the inner diameter is 400-900 microns; the outer diameter of the small glass capillary and the large-nosed glass capillary is 300-800 microns, and the inner diameter is 200-700 microns; the small-tip glass The outer diameter of the capillary is 100-600 microns and the inner diameter is 50-500 microns; the ratio of the internal diameter of the large-nosed glass capillary to the internal diameter of the nozzle is greater than 1 and less than 10, and the internal and internal diameters of the small-nosed glass capillary The ratio is greater than 1 and less than 10.

The sealant is epoxy resin.

Example 1:

(1) Using a 10ml syringe, take 9ml heptadecane as the dispersed phase 1, use a 10ml syringe to take 9ml HDDA containing 2% by mass of Span 80 and 2% by mass of the light curing agent as the dispersed phase 2, and use a 20ml syringe to take 15ml 2% by mass of a polyvinyl alcohol aqueous solution is used as a continuous phase; the dispersed phase 1, the dispersed phase 2 and the continuous phase are respectively pushed from a syringe pump into a Teflon catheter and passed into a double emulsified glass capillary microfluidic chip, in which the dispersed phase 1 is the microfluidic chip from the small-tip glass capillary, the dispersed phase 2 is the microfluidic chip from the first closed reservoir, the continuous phase is the microfluidic chip from the second closed reservoir; the injection pump is adjusted The flow rates were 150 μl / min, 50 μl / min, and 10 μl / min, respectively;

(2) Use an ultraviolet light source to irradiate the end of the small glass capillary of the microfluidic chip, and collect the solidified capsule at the exit of the small glass capillary; (The ultraviolet wavelength of the ultraviolet light source is 360 nm. (The irradiance of the end is greater than 100mW / cm ² )

(3) The capsule obtained in step (3) is filtered, repeatedly washed three times with deionized water and absolute ethanol, and dried at room temperature to obtain a shell thickness of about 100 μm, a capsule core diameter of about 300 μm, and a total diameter of about 500 μm. Phase change microcapsules with a polydispersity coefficient of less than 3%.

Example 2:

The flow rate of the syringe pump was adjusted to 150 μl / min, 20 μl / min, and 10 μl / min, respectively. The other steps were the same as in Example 1. The thickness of the finally obtained capsule shell is about 50 μm, the diameter of the capsule core is about 240 μm, the total diameter of the capsule is about 340 μm, and the polydispersity coefficient is less than 3%.

Example 3

The flow rate of the syringe pump was adjusted to 800 μl / min, 5 μl / min, and 5 μl / min, respectively. The other steps were the same as in Example 1. The thickness of the finally obtained capsule shell is about 10 μm, the diameter of the capsule core is about 20 μm, the total diameter of the capsule is about 60 μm, and the polydispersity coefficient is less than 3%.

The above embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above embodiment. Any other changes, modifications, substitutions, combinations, and modifications made without departing from the spirit and principle of the present invention, Simplified, all should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims

A double-emulsified glass capillary microfluidic chip, which is characterized by comprising a large glass capillary, a small glass capillary, a large-nosed glass capillary, a small-nosed glass capillary, two conical centrifuge tubes, and a glass slide base;

Only the exit end of the large-nosed glass capillary and the small-nosed glass capillary are pointed. The small-nosed glass capillary is coaxially inserted into the inside of the large-nosed glass capillary, and the two-nosed nozzles are located on the same side. The distance is 10-500 microns; the large-nosed glass capillary is inserted in the direction of the pointed glass capillary from the entrance of the large glass capillary, the small glass capillary is inserted from the large glass capillary exit, and the pointed tip of the large-nosed glass capillary extends into the small glass capillary. 10-100 microns; large glass capillary placed on a glass slide abutment;

The two conical centrifuge tubes are inverted at the entrances of the large-tip glass capillary and the large-capillary glass capillary, respectively, and are used between the conical centrifuge tube, the large-tip glass capillary, the small-tip glass capillary and the slide base. The sealant forms a first closed liquid storage tank, and the sealant forms a second closed liquid storage tank between the conical centrifuge tube, the large glass capillary tube, the large-nosed glass capillary tube, and the glass slide base;

The inlets of the small-nosed glass capillary and the two conical centrifuge tubes are connected to three syringe pumps through Teflon catheters, respectively.
The dual-emulsified glass capillary microfluidic chip according to claim 1, wherein the large glass capillary has an outer diameter of 500-1000 microns and an inner diameter of 400-900 microns; a small glass capillary and a large pointed mouth The outer diameter of the glass capillary is 300-800 microns, and the inner diameter is 200-700 microns; the outer diameter of the small-tip glass capillary is 100-600 microns, and the inner diameter is 50-500 microns; The ratio of the inner diameter of the pointed mouth is greater than 1 and less than 10, and the ratio of the internal diameter of the small capillary glass capillary to the inner diameter of the pointed mouth is greater than 1 and less than 10.
The dual-emulsion glass capillary microfluidic chip according to claim 1, wherein the sealant is an epoxy resin adhesive.
A method for preparing a phase change microcapsule by using the double emulsified glass capillary microfluidic chip according to claim 1, comprising the following steps:

(1) Disperse phase 1, dispersed phase 2 and continuous phase are pushed into the Teflon catheter from the syringe pump and passed into the double emulsified glass capillary microfluidic chip. Among them, dispersed phase 1 is introduced into the microfluid from the small-tip glass capillary. Control chip, dispersed phase 2 is passed from the first closed liquid storage tank into the microfluidic chip, and continuous phase is passed from the second closed liquid storage tank into the microfluidic chip;

(2) using an ultraviolet light source to irradiate the end of the small glass capillary of the microfluidic chip, and collect the cured capsule at the outlet of the small glass capillary;

(3) The capsule obtained in step (2) is filtered, repeatedly washed with deionized water and anhydrous ethanol, and dried at room temperature to obtain a phase change microcapsule with controllable thickness and capsule core.
The method according to claim 4, characterized in that: the dispersed phase 1 in step (1) is a phase change material; the dispersed phase 2 is a mixture of a photocuring agent monomer, a surfactant 1 and a photoinitiator, The mass fraction of surfactant 1 is 0-3%, the mass fraction of photoinitiator is 1-2%; the continuous phase is a mixture of surfactant 2 and water, and the mass fraction of surfactant 2 is 1-10%.
The method according to claim 5, characterized in that: the phase change material is an alkane or an alkane halide; the photocuring agent monomer is an unsaturated polyester resin; and the surfactant 1 is an oil-soluble ionic or Non-ionic surfactant; the photoinitiator is Dejian 1173; the surfactant 2 is a water-soluble ionic or non-ionic surfactant.
The method according to claim 5, characterized in that: the phase change material is heptadecane; the photocuring agent monomer is 1,6-hexanediol diacrylate; and the surfactant 1 is a company Disc 80; the surfactant 2 is polyvinyl alcohol.
The method according to claim 4, characterized in that: the injection pump in step (1) separately controls the three-phase flow rate into the microfluidic chip, wherein the flow rate of the dispersed phase 1 is 2-30 μl / min, and the dispersion is performed. The flow rate of phase 2 is 5-50 μl / min, and the flow rate of continuous phase is 50-500 μl / min.
The method according to claim 4, wherein: the step (2) of the ultraviolet light source of 360 nm wavelength ultraviolet light, the irradiation intensity of the small end of the glass capillary tube is greater than 100mW / cm 2.
A phase change microcapsule prepared by the method according to any one of claims 4 to 9, characterized in that the phase change microcapsule is made of polyester resin as a wall material and alkane or alkane halide as The core material is composed of a capsule core with a controllable size in the range of 30-500 μm, a capsule wall thickness in the range of 1-200 μm, and the overall capsule size range of 30-600 μm. The phase change microcapsule particle size deviation is less than 4 μm. The phase change microcapsules of the prepared size have a specific gravity greater than 70% and a core material mass content of 50-90%.