KR102546952B1 - Surface modification method of microcapsules using microcracks and modified microcapsules using the same method - Google Patents

Abstract

The present invention relates to a method for modifying the surface of microcapsules, and more specifically, by applying mechanical stress to microcapsules including a highly reactive core material and a polymer shell surrounding the core material to form microcracks in the polymer shell, The present invention relates to a method for modifying the surface of microcapsules using microcracks capable of modifying the surface of a polymer shell into a specific functional group by reacting a core material flowing out through microcracks with a continuous phase.

Description

Surface modification method of microcapsules using microcracks and modified microcapsules using the same method}

The present invention relates to a method for modifying the surface of microcapsules, and more specifically, by applying mechanical stress to microcapsules including a highly reactive core material and a polymer shell surrounding the core material to form microcracks in the polymer shell, The present invention relates to a method for modifying the surface of microcapsules using microcracks capable of modifying the surface of a polymer shell into a specific functional group by reacting a core material flowing out through microcracks with a continuous phase.

The process of manufacturing microcapsules using microfluidic devices is attracting attention in a wide range of fields including drug delivery, environment, biological and medical sensors due to the high embedding efficiency and structural uniformity of the core material, and these microcapsules have various functionalities. is very important for practical applications.

In general, microcapsules include a core material and a shell for confining the core material, and a polymer material is mainly used to form the shell.

Here, the polymer material is easy to introduce additional functionality by controlling the structure and characteristics of the surface layer while maintaining the physical properties of the parent material through surface modification.

A surface modification method of a microcapsule using a conventional microfluidic device applies a surface modification process of imparting a specific functional group to the surface of the shell while forming double emulsion droplets using a microfluidic device.

However, in the conventional microcapsule surface modification method using a microfluidic device, when the internal phase constituting the core material is used as a highly reactive material, the reaction between the core material and the shell, the reaction between the core material and functional groups, or the above Due to the reaction between the reactant of the shell and the functional group and the core material, there are restrictions on the type of polymer and functional group for forming the shell, and as a result, there is a limit in that a highly reactive core material cannot be applied.

The present invention has been made to solve these problems, and an object of the present invention is to manufacture a microcapsule so that the core material is confined inside the polymer shell, and then to form microcracks in the polymer shell to release through the microcracks. It is to provide a method for modifying the surface of microcapsules using microcracks in which a highly reactive core material can be used while modifying the surface of the shell to impart a specific functional group by reacting the continuous phase with the core material to be formed.

The objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the description below.

In order to achieve the above object, the present invention provides a microcapsule manufacturing step of manufacturing a microcapsule including a core material and a polymer shell surrounding the core material; Microcrack formation step of forming microcrack in the polymer shell by applying mechanical stress to the prepared microcapsule; and a surface modification step of reacting the core material flowing out through the microcracks with the continuous phase to form a surface modification layer functioning as a specific functional group on the surface of the polymer shell. do.

In a preferred embodiment, the polymer shell is composed of a polymer monomer that does not undergo an organic chemical reaction on the surface when in a solid state.

In a preferred embodiment, the manufacturing step of the microcapsule is performed by crosslinking the intermediate phase while forming a double droplet including an internal phase constituting the core material and an intermediate phase constituting the polymer shell using a microfluidic device. The polymer shell is formed from the polymer backbone.

In a preferred embodiment, the microfluidic device includes an outer tube open at both ends; an inner tube having both ends open and provided inside one side of the outer tube, into which an inner phase is introduced; Both ends are open and provided on the inside of the other side of the outer tube so as to face the one side inner tube, and the other inner tube into which the outer phase is introduced, and an intermediate phase is introduced between the outer tube and the one inner tube , An external phase is introduced between the outer tube and the other inner tube.

In a preferred embodiment, one opening of the other inner tube has a larger diameter than the other opening of the one inner tube facing the other inner tube.

In a preferred embodiment, the internal phase contains a first reactant molecule and a surfactant, and the surfactant is a water-soluble surfactant or an oil-soluble surfactant.

In a preferred embodiment, the first reactive molecule is at least one of an alcohol, an aldehyde, a carboxylic acid, an amine, and an imine.

In a preferred embodiment, the first reactive molecule is 10 parts by weight to 50 parts by weight based on 100 parts by weight of the internal phase.

In a preferred embodiment, the intermediate phase includes an acryl lake-based polymer and a cross-linking agent capable of cross-linking the acrylate-based polymer.

In a preferred embodiment, the acrylate-based polymer is ethylene glycol diacrylate (ethylenlycoldiacrylate, EGDA), trimethylolpropane triacrylate (TMPTA), trimethylolpropaneethoxy triacrylate (ethoxylated trimethylolpropane triacrylate) , ETPTA), ethoxylated bisphenol A dimethacrylate, hexandioldiacrylate (HDA), tripropyleneglycoldiacrylate (TPGDA), tetraethylene glycol diacrylate Composed of tetraethylene glycol diacrylate, glycerol propoxylate triacrylate (GPTA), pentaerythritol tetraacrylate (PETA) and dipentaerythritol hexaacrylate (DPHA) It is at least one selected from the group.

In a preferred embodiment, the outer phase contains a water-soluble or oil-soluble surfactant.

In a preferred embodiment, the continuous phase includes second reactive molecules, and the second reactive molecules undergo a physical or chemical reaction with the first reactive molecules.

In a preferred embodiment, in the microcrack forming step, the mechanical stress is formed by heating.

In a preferred embodiment, the microcrack formation step is heated to a temperature higher than the boiling point of the first reactant molecule and lower than the boiling point of the continuous phase.

In a preferred embodiment, in the step of forming the microcracks, the microcracks are formed in the polymer shell, and at the same time, the first reactant molecule flows out through the microcracks.

In addition, the present invention further provides microcapsules manufactured by the method for modifying the surface of microcapsules according to the present invention.

In a preferred embodiment, the microcapsule is a core material; A polymer shell surrounding the core material and having microcracks formed thereon; and a surface modification layer formed on the surface of the polymer shell and functioning as a specific functional group.

In addition, the present invention may be provided as an adsorbent including the microcapsule or a microreactor including the microcapsule.

The present invention has the following excellent effects.

According to the method of modifying the surface of microcapsules using microcracks of the present invention, microcapsules are manufactured so that the core material is confined inside the polymer shell, and then microcracks are formed in the polymer shell, so that the core is discharged through the microcracks. By reacting the material with the continuous phase, a highly reactive core material can be used, and the surface of the shell can be modified to attach various functional groups.

In addition, according to the surface modification method of microcapsules using microcracks of the present invention, the microcrack formation step is performed under optimal conditions, thereby providing functionalized microcapsules with excellent adsorption and desorption performance.

In addition, according to the surface modification method of microcapsules using microcracks of the present invention, it has an advantage that it can be provided as a drug delivery system, various sensors, and the like.

1 is a step diagram illustrating a method for modifying the surface of a microcapsule according to the present invention.
2 is a diagram for explaining a microfluidic device used in the microcapsule manufacturing step according to the present invention.
Figure 3 is a schematic diagram for explaining the surface modification step according to the present invention, (a) is a schematic diagram before microcracks and surface modification, (b) is a schematic diagram after microcracks and surface modification.
4 is an image of the surface of Comparative Example and Example 3 according to the present invention observed with an optical microscope and a cross-section image observed with a scanning electron microscope.
5 is a Fourier transform infrared (FT-IR) spectroscopic analysis spectrum of Comparative Example and Example 3 according to the present invention.
6 is an image of Examples 1 to 6 according to the present invention observed with an optical microscope.
7 is an image observed with an optical microscope after adsorbing copper ions to Examples 1 to 6 according to the present invention.
8 is a graph obtained by measuring the copper ion adsorption efficiency of Examples 1 to 6 according to the present invention through inductively coupled plasma (ICP-OES) spectroscopic analysis.
9 is a graph obtained by measuring adsorption amounts of copper ions, zinc ions, and cadmium ions of Example 3 according to the present invention through inductively coupled plasma spectroscopy.
10 is a result of performing the copper ion adsorption and desorption amount of Example 3 according to the present invention 5 times.

The terms used in the present invention have been selected from general terms that are currently widely used as much as possible, but in certain cases, there are terms arbitrarily selected by the applicant. Therefore, its meaning should be understood.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Like reference numbers indicate like elements throughout the specification.

On the other hand, the "internal phase", "intermediate phase" and "external phase" used in the present invention may be a water phase or an oil phase, which is a phase for forming double droplets of water-in-oil-in-water or oil-in-water in a microfluidic device, or a combination thereof. includes

1 is a step diagram illustrating a method for modifying the surface of a microcapsule according to the present invention.

Referring to FIG. 1, a method for modifying the surface of microcapsules according to an embodiment of the present invention uses a highly reactive material as a core material to attach various functional groups to the surface of the microcapsules without any restrictions on the type of microcapsules. It is a surface modification method of

2 is a diagram for explaining a microfluidic device used in a microcapsule manufacturing step according to the present invention. First, a microcapsule manufacturing step (S100) of manufacturing a microcapsule is performed.

The microcapsule 100 includes a core material 110 and a polymer shell 120 surrounding the core material 110 .

Here, the core material 110 is formed by the internal phase 20 .

In addition, the internal phase 20 includes first reactive molecules 21 and a surfactant 22 .

At this time, at least one of alcohol, aldehyde, carboxylic acid, amine, and imine may be used as the first reactive molecule 21 .

In addition, the first reactive molecule 21 is not limited as long as it is a material capable of inducing an organic chemical reaction with the second reactive molecule 51 included in the continuous phase used in the surface modification step (S300) to be described later.

In addition, the first reactive molecule 21 is preferably used in an amount of 10 to 50 parts by weight based on 100 parts by weight of the internal phase 20 .

In addition, the surfactant 22 may be a water-soluble surfactant or a fat-soluble surfactant.

In this case, the content of the surfactant 22 may include 0.1 part by weight to 10 parts by weight based on 100 parts by weight of the entire internal phase 20.

For example, polyethyleneglycol (PEG), poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), polyoxyethylenesorbitan monooleate (Tween 80) or sorbitan monooleate (Span 80) may be used as the surfactant.

The polymer shell 120 may be composed of a single monomer or multiple molecules, and is formed into a cross-linked polymer skeleton that confines the core material 110 after solidification.

In addition, the polymer shell 120 is formed by the intermediate phase 30, and in the case of a solid phase, it is preferable to be composed of a polymer monomer that does not cause an organic chemical reaction on the surface.

In addition, the intermediate phase 30 may include an acrylate-based polymer and a cross-linking agent capable of cross-linking the acrylate-based polymer.

Here, the acrylate-based polymer is ethylene glycol diacrylate (ethylenlycoldiacrylate, EGDA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy triacrylate (ethoxylated trimethylolpropane triacrylate, ETPTA), Ethoxylated bisphenol A dimethacrylate, hexandioldiacrylate (HDDA), tripropyleneglycoldiacrylate (TPGDA), tetraethylene glycol diacrylate), glycerol propoxylate triacrylate (GPTA), pentaerythritol tetraacrylate (PETA) and dipentaerythritol hexaacrylate (DPHA) selected from the group consisting of At least one of them may be used.

In addition, the crosslinking agent may include a photoinitiator and a thermal initiator, and the crosslinking agent is not limited as long as it is a material capable of inducing crosslinking of polymer monomers.

For example, the crosslinker is 2-hydroxy-2-methyl-1-phenylpropan-1-one (2-Hydroxy-2-methyl-1-phenylpropan-1-one), 2,2-dimethoxy- 1,2-diphenylethanone (2,2-Dimethoxy-1,2-di (phenyl) ethanone), 2-hydroxy-4'- (2-hydroxyethoxy) -2-methylpropiophenone ( 2-Hydroxy-4'-(2-hydroxyethoxy)-2 methylpropiophenone), 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropan-1-one -1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropan-1-one), 1-Hydroxycyclohexyl benzophenone, 1-Hydroxycyclohexyl phenyl ketone phenylketone), N,N'-methylenebis(acrylamide), and 2,2'-azobis(2-methyl-propioamidine) dihydrochloride (2,2' At least one of -Azobis(2-methyl-propioamidine)dihydrochloride) may be used.

At this time, the content of the crosslinking agent is preferably 0.01 part by weight to 1 part by weight based on 100 parts by weight of the intermediate phase (30).

Meanwhile, in the microcapsule manufacturing step (S100), the microcapsule 100 may be manufactured using a microfluidic device.

Hereinafter, with reference to FIG. 2, the microfluidic device and the microcapsule manufacturing step (S100) using the microfluidic device will be described in more detail.

The microcapsule manufacturing step (S100) is manufactured using the microfluidic device, the inner phase 20 constituting the core material 110 and the intermediate phase 30 constituting the polymer shell 120 The intermediate phase 30 is cross-linked while forming a double droplet comprising the polymer shell 120 to be formed as a polymer backbone.

Here, the double droplet means that it includes the inner phase 20, the middle phase 30 and the outer phase 40.

The microfluidic device includes an outer tube 11, an inner tube 12 on one side, and an inner tube 130 on the other side.

Here, the outer tube 11 is provided with both ends open, and the one side inner tube 12 is provided inside one side of the outer tube 11, and the inner phase 20 is provided inside from one side to the other side. The other inner tube 13 has both ends open and is provided on the inside of the other side of the outer tube 11 so as to face the one inner tube 12, and the outer phase 40 is provided on the other side. flows in one direction.

In addition, between the outer tube 11 and the inner tube 12 on one side, the intermediate phase 30 is introduced from one side to the other side, and between the outer tube 11 and the inner tube 13 on the other side, from the other side to one side. In this direction, the external phase 40 is introduced.

In this case, the external phase 40 may include a water-soluble surfactant or a fat-soluble surfactant, and the same surfactant as that of the internal phase 20 may be used as the surfactant.

In addition, the weight ratio of the surfactant may include 0.1 part by weight to 10 parts by weight based on 100 parts by weight of the entire outer phase 400.

In addition, the one side opening 13a of the other inner tube 13 has a larger diameter than the other side opening 12a of the one side inner tube 12 facing the other inner tube 12a.

Accordingly, when the microfluidic device is operated using a syringe pump, the internal phase 20 and the intermediate phase 30 are injected from one side to the other, and the external phase 40 is injected from the other side to one side. The inner phase 20 is formed as a single droplet in the oil phase at the other opening 12a of the one inner tube 12, and this single droplet is formed as a single droplet at the other opening 12a of the other inner tube 12a, Orifice) is formed as a double droplet in the continuous phase 40.

At the same time, light (UV) is continuously irradiated at a position adjacent to the other opening 12a, and the polymer monomers in the intermediate phase 30 are crosslinked to form the polymer shell 120 of the polymer skeleton, which is manufactured as a microcapsule. do.

At this time, heat, pH change, or ions may be used instead of light to crosslink the intermediate phase 30 .

Here, since the polymer skeleton has sufficient mechanical durability, the core material 120 confined therein is not allowed to flow out or spread to the outside before the microcrack formation step (S200) to be described later.

In addition, the diameter of the microcapsule 100 may be 50 μm to 500 μm.

Next, a microcrack formation step (S200) is performed in which a microcrack (a) is formed in the polymer shell 120 by applying mechanical stress to the microcapsule 100.

Here, the mechanical stress may be formed by stirring and heating.

At this time, the temperature of the heat applied to the microcapsules 100 is heated to a temperature higher than the boiling point of the first reactive molecule 21, and is preferably heated to a temperature lower than the boiling point of the continuous phase 50 described later.

This is to ensure that the mechanical stress applied to the microcapsule by boiling of the core material 110 does not exceed the Young's modulus of the polymer shell 120, and thus the structure of the polymer shell 120 Micro cracks (a) that are not destroyed may be formed, and the core material 110 may flow out through the formed micro cracks (a).

That is, microcracks (a) are formed in the polymer shell 120 through the microcrack formation step (S200), and at the same time, the core including the first reaction molecule 21 is formed through the microcracks (a). Substance 110 is to flow out.

Accordingly, before the microcrack formation step (S200), since the core material 110 is confined inside the polymer shell 120 without contamination, the core material 110 can be applied as a highly reactive material. will be.

For example, in the microcrack formation step (S200), heating may be performed at a temperature of 165 ° C. for 6 to 9 hours, and the temperature and heating time depend on the components of the core material and the components of the polymer shell. can be adjusted

In addition, the continuous phase in which the microcapsules are dispersed must be composed of a material having a boiling point higher than that of the core material, because uniform heat transfer to the core material can be ensured during the formation of heat-induced microcracks.

Next, as shown in FIG. 3, the polymer shell is reacted with the core material 110 flowing out through the microcrack (a) formed through the microcrack formation step (S200) and the continuous phase 50. A surface modification step (S300) of forming a surface modification layer 130 functioning as a specific functional group on the surface of (120) is performed.

Here, the continuous phase 50 includes the second reactive molecule 51, which is a material capable of inducing a physical or chemical reaction with the core material 110, and the physical or chemical reaction depends on a specific reaction. It is not limited and may include complex reactions.

That is, a physical or chemical reaction occurs between the first reactive molecules 21 and the second reactive molecules 51 flowing out through the microcracks (a), thereby forming the surface modification layer 130 functioning as a specific functional group. will be formed

However, when the surface modification step (S300) proceeds after the microcrack formation step (S200), since there is a concern that the core material 110 does not remain inside the microcapsule 100, the microcrack formation Step (S200) and the surface modification step (S300) are preferably performed simultaneously.

Accordingly, the surface modification method of microcapsules according to the present invention can be applied to functional groups having adsorption performance, introduction of functional groups for additional surface modification, and multifunctional microcapsules.

In addition, the present invention further provides a microcapsule 100 manufactured by the surface modification method of the microcapsule according to the present invention.

The microcapsule 100 surrounds the core material 110, the core material 110, and is formed on the surface of the polymer shell 120 and the polymer shell 120 on which microcracks are formed, and the surface functions as a specific functional group. A modified layer 130 is included.

In addition, the present invention may be provided as an adsorbent including the microcapsule or a microreactor including the microcapsule.

Here, the microreactor means a miniaturized reaction system manufactured by applying microtechnology and precision engineering.

Example 1

One inner tube (12) and the other inner tube (13) (1.0 mm OD, 0.58 mm ID, Sutter) assembled in a rectangular outer tube (11) (1.3 mm OD, 1 mm ID, Friedrich & Dimmock, Inc.) Instrument) was used to prepare microcapsules.

At this time, the outer tube 11 was fixed to the transparent slide glass using an ultraviolet curing adhesive, the diameter of the other side opening 12a of one inner tube 12 was 140 μm, and one side opening of the other inner tube 13 (13a) is 270 μm.

2-[methoxy(polyethyloxy)6-9propyl]trimethoxysilane (2-methoxy(polyethyleneoxy)6-9propyl)trimethoxysilane; Gelest) for 30 minutes to make the surface hydrophobic, and the other inner tube 13 was immersed in trimethoxy (octadecyl) silane (Sigma-Aldrich) to make the surface hydrophilic. .

After washing the one inner tube 12 and the other inner tube 13 with isopropanol and distilled water, both inner tubes are completely dried, and the gap between the one inner tube 12 and the other inner tube 13 is reduced. It was installed at 250 μm.

To prepare the microcapsules 100, 10 parts by weight of polyvinyl alcohol (PVA, Mw 13,000-23,000 g/mol, Sigma-Aldrich) aqueous solution and 50 parts by weight of glutaraldehyde (GA, 50 %, Sigma-Aldrich) was used, and trimethylolpropane containing 5 parts by weight of photoinitiator (2-hydroxy-2-methylpropiophenone, Darocur 1173, 97%, Sigma-Aldrich) as the intermediate phase (30) Ethoxylated trimethylolpropane triacrylate (ETPTA) was used.

And 10 parts by weight of PVA aqueous solution was used as the external phase (40). Flow rates of the inner phase 20, the middle phase 30, and the outer phase 40 were set to 240, 300, and 6000 μL/h, respectively.

The internal phase 20, the intermediate phase 30 and the external phase 40 were injected with the flow depicted in FIG. 2 using a syringe pump connected to the microfluidic device, and the internal phase 20 was injected through the other opening 12a. A single droplet formed in the oil phase in the vicinity, which reached the vicinity of the orifice and formed a double droplet in the continuous phase 50, which occurred simultaneously.

Thereafter, ETPTA, a polymer monomer of the double droplet, was crosslinked by continuous light irradiation, and the microcapsules prepared by forming a crosslinked polymer backbone were immersed in 10 parts by weight of PVA aqueous solution.

Next, after washing the immersed microcapsules with distilled water, they were transferred to ethylene glycol (EG) containing 10 parts by weight of polyethyleneimine (PEI, Mw 25,000 g/mol, branched, Sigma-Aldrich), and microcapsules containing By heating the PEI solution to 135 ° C. with a heater and stirring it at 250 rpm for 6 hours using a mechanical stirrer, microcracks were formed in the polymer shell, and GA leaked out through the microcracks interacted with PEI present in the continuous phase. Example 1 was obtained by modifying the surface through a Schiff base reaction.

Example 2

Compared to Example 1, microcapsules prepared under the same conditions as in Example 1 were obtained, except that the heating and mechanical stirring time were treated for 9 hours.

Example 3

Compared to Example 1, microcapsules were obtained under the same conditions as in Example 1, except that the heating temperature was 165°C.

Example 4

Compared to Example 3, microcapsules prepared in the same conditions as in Example 3 were obtained except for heating and mechanical stirring for 9 hours.

Example 5

Compared to Example 1, microcapsules prepared under the same conditions as in Example 1 were obtained except that the heating temperature was 195°C.

Example 6

Compared to Example 5, microcapsules prepared in the same conditions as in Example 5 were obtained except for heating and mechanical stirring for 9 hours.

comparative example

Microcapsules were obtained under the same conditions as in Example 1, except that heating and mechanical stirring were not performed in Example 1.

Experimental Example 1 (Process for manufacturing microcapsules and heat-induced microcracks and shape and surface analysis of surface-modified microcapsules)

Microcapsules modified by the surface modification method of microcapsules according to the present invention were prepared using water-in-oil-in-water (W/O/W) double emulsion droplets as templates. The core of the double emulsion droplet contains GA, a material capable of reacting with the material contained in the continuous phase in the subsequent surface modification step, and the oil shell forms a polymer shell through photopolymerization, and the polymer shell is the core material It has sufficient mechanical strength to confine it without external contamination, but has the property of inducing outflow of the core material without structural destruction of the microcapsule through microcracks formed in the polymer shell. The microcapsules according to the present invention have an average diameter of 197.5 μm and a coefficient of variation (CV) of 5.01%.

In addition, in the microcapsules modified by the surface modification method of the microcapsules according to the present invention, GA flows out of the microcapsules through heat-induced microcracks, and Schiff base reaction with PEI present in the continuous phase Through this, the surface of the microcapsule is modified.

Figure 4 is an image of the surface of the microcapsules prepared in Comparative Example and Example 3 observed with an optical microscope and a cross-section image observed with a scanning electron microscope, (a) is a surface image of the comparative example observed with an optical microscope and It is a cross-sectional image observed with a scanning electron microscope, and (b) is a cross-sectional image observed with a scanning electron microscope and the surface of Example 3 observed with an optical microscope.

Referring to FIG. 4 (a), in the case of the comparative example, heating and mechanical stirring were not performed, so there were no microcracks on the surface and cross section of the polymer shell, and it was confirmed that there were no other characteristics.

However, as shown in FIG. 4(b), in the case of Example 3, heating and mechanical stirring were performed to form microcracks on the surface of the polymer shell, and in the colorless accompanying Schiff base reaction of GA and PEI molecules. It was confirmed that a color change to yellow appeared.

In addition, in order to qualitatively analyze functional groups attached as a result of surface modification of microcapsules modified by the surface modification method of microcapsules according to the present invention, using Comparative Example and Example 3, Fourier transform infrared (FT-IR) ) Spectroscopic analysis was performed, and the results are shown in FIG. 5 and Table 1 below.

Wavelength (cm ^-1 ) Corresponding functional group vibration the corresponding molecule comparative example 3600-3100 O-H stretching PVA 2949, 2852 C-H stretching PVA, GA 1717 C=O stretching GA 1644 C=O stretching ETPTA 1436 C-H stretching PVA, GA 1361 O-H stretching PVA 1256, 1106, 1021 C-O stretching PVA, ETPTA 948 O-H stretching PVA Example 3 3600-3100 OH stretching
NH stretching PVA, PEI 2949, 2852 C-H stretching PVA, PEI, GA 1651 C=N stretching Schiff base reaction 1541 N-H stretching PEI 1418 C-H stretching PVA, PEI GA 1084 C-N stretching PEI 1041 C-O stretching PVA, ETPTA

Referring to FIG. 5 and Table 1, in the case of the comparative example, the PEI component was not included on the surface because no microcracks were formed, but in the case of Example 3, the surface was modified through reaction with the GA component leaked through the microcracks to obtain PEI It was confirmed that the component was included.

In addition, in order to further study the effect of temperature and time of heating and mechanical stirring on surface modification through heat-induced microcrack formation, Examples 1 to 6 were observed with an optical microscope as shown in FIG. 6, It was confirmed that there was no significant change in appearance between the surface-modified microcapsules through thermally induced microcracks.

Experimental Example 2 (Analysis of adsorption performance of microcapsules)

The microcapsules according to the present invention provided as an example of a method for surface modification of microcapsules through thermally induced microcracking exhibit high adsorption performance for heavy metal ions due to the amine group included in PEI on the surface.

In order to examine the adsorption rate and adsorption amount of the microcapsules functionalized with PEI, the microcapsules 0.1 of Comparative Example and Examples 1 to 6 were immersed in a copper nitrate aqueous solution at a concentration of 3000 mg/L and adsorbed for 2 hours. proceeded. After that, the results observed with an optical microscope are shown in FIG. 7 .

In the case of the comparative example, it was confirmed that no change was observed on the surface because it was not functionalized with PEI, and in contrast, in the case of Examples 1 to 6, it was confirmed that the yellow surface changed to blue. This means that copper ions are adsorbed on the microsurface.

8 shows the results of quantitatively analyzing the effect of the temperature and time of heating and mechanical stirring on the adsorption amount of copper ions in the microcrack formation step (S200) through inductively coupled plasma (ICP-OES) spectroscopic analysis. was

Referring to FIG. 8, although it was difficult to confirm the result of the optical microscope measurement, the change in the adsorption amount of copper ions gradually increased with the heating temperature and time, and was saturated with an adsorption efficiency of 85.2% at a specific temperature and time, Through this, it was concluded that it is necessary to adjust the temperature and time to optimize the surface modification.

In addition, in order to further study the adsorption characteristics of the microcapsules functionalized with PEI, the results of measuring the adsorption amount of three heavy metal ions and the adsorption / desorption efficiency of copper ions using Example 3 are shown in FIGS. 9 and 10 was

0.1 g of Example 3 was separately transferred to an aqueous solution in which copper nitrate, zinc nitrate, and cadmium nitrate were dissolved at a concentration of 3000 mg/L, and the adsorption amount was measured. The microcapsules in which the adsorption of copper ions was completed were transferred to an aqueous solution of 0.1 N hydrochloric acid for desorption at room temperature for 2 hours, and then the Example 3 was filtered, washed several times with distilled water, dried, and reused for adsorption of copper ions. This process was repeated 5 times to measure adsorption and desorption efficiencies.

Referring to FIGS. 9 and 10 , Example 3 showed high adsorption amounts of 231.83 mg/g, 218.92 mg/g, and 119.1 mg/g for copper, zinc, and cadmium ions, respectively.

In addition, after repeating the adsorption/desorption process 5 times, the adsorption amount decreased from 231.83 mg/g to 181.65 mg/g, and the desorption amount decreased from 178.91 mg/g to 172.76 mg/g, but the absorption/desorption amount was reduced with high efficiency of about 80% or more. Desorption performance was maintained. Such high adsorption performance and adsorption/desorption efficiency suggest that surface modification of microcapsules is permanent rather than temporary.

As described above, in the method for surface modification of microcapsules and microcapsules according to the present invention, microcapsules are manufactured so that the core material is confined inside the polymer shell, and then microcracks are formed in the polymer shell to form microcracks through microcracks. By reacting the discharged core material with the continuous phase, there is an effect of modifying the surface of the shell to attach various functional groups while using a highly reactive core material.

In addition, according to the surface modification method of microcapsules using microcracks of the present invention, the microcrack formation step is performed under optimal conditions, thereby providing functionalized microcapsules with excellent adsorption and desorption performance, and furthermore, various functional groups By modifying to be attached, it can be used as a drug delivery system, various sensors, and the like.

As described above, the present invention has been shown and described with preferred embodiments, but is not limited to the above embodiments, and to those skilled in the art within the scope of not departing from the spirit of the present invention Various changes and modifications will be possible.

100: microcapsule 110: core material
120: polymer shell 130: surface modification layer
11: outer tube 12: one inner tube
13: other inner tube 20: inner top
30: middle phase 40: external phase
50: continuous phase a: microcracks

Claims (19)

A microcapsule manufacturing step of manufacturing a microcapsule including a core material and a polymer shell surrounding the core material;
Microcrack formation step of forming microcrack in the polymer shell by applying mechanical stress to the prepared microcapsule; and
A surface modification step of forming a surface modification layer functioning as a specific functional group on the surface of the polymer shell by reacting the core material flowing out through the microcracks with the continuous phase;
According to claim 1,
The surface modification method of the microcapsule, characterized in that the polymer shell is composed of a polymer monomer that does not cause organic chemical reactions on the surface when in a solid state.
According to claim 1,
In the manufacturing step of the microcapsule, a double droplet including an inner phase constituting the core material and an intermediate phase constituting the polymer shell is formed by using a microfluidic device, and the intermediate phase is crosslinked so that the polymer shell is a polymer backbone. Method for surface modification of microcapsules, characterized in that to form.
According to claim 3,
The microfluidic device
An outer tube open at both ends;
an inner tube having both ends open and provided inside one side of the outer tube, into which an inner phase is introduced;
Both ends are open and provided on the inside of the other side of the outer tube so as to face the one side inner tube, and the other inner tube into which the external phase is introduced; includes,
The surface modification method of microcapsules, characterized in that the intermediate phase is introduced between the outer tube and the one inner tube, and the outer phase is introduced between the outer tube and the other inner tube.
According to claim 4,
The surface modification method of the microcapsule, characterized in that one opening of the other inner tube is provided with a larger diameter than the other opening of the one inner tube facing the other inner tube.
According to claim 4,
The internal phase includes a first reactant molecule and a surfactant,
The surface-modifying method of the microcapsules, characterized in that the surfactant is a water-soluble surfactant or a fat-soluble surfactant.
According to claim 6,
Wherein the first reactive molecule is at least one of an alcohol, an aldehyde, a carboxylic acid, an amine, and an imine.
According to claim 6,
The surface modification method of the microcapsule, characterized in that the first reactive molecule is 10 parts by weight to 50 parts by weight based on 100 parts by weight of the inner phase.
According to claim 4,
The method of modifying the surface of microcapsules, characterized in that the intermediate phase comprises an acrylate-based polymer and a crosslinking agent capable of crosslinking the acrylate-based polymer.
According to claim 9,
The acrylate-based polymer includes ethylenlycoldiacrylate (EGDA), trimethylolpropane triacrylate (TMPTA), ethoxylated trimethylolpropane triacrylate (ETPTA), ethoxy Ethoxlyated bisphenol A dimethacrylate, hexanedioldiacrylate (HDDA), tripropyleneglycoldiacrylate (TPGDA), tetraethylene glycol diacrylate , At least any one selected from the group consisting of glycerol propoxylate triacrylate (GPTA), pentaerythritol tetraacrylate (PETA) and dipentaerythritol hexaacrylate (DPHA) A method for surface modification of microcapsules, characterized in that one.
According to claim 1,
The external phase is a method for modifying the surface of microcapsules, characterized in that it contains a water-soluble or fat-soluble surfactant.
According to claim 6,
The continuous phase includes second reactive molecules, and the second reactive molecules undergo a physical or chemical reaction with the first reactive molecules.
According to claim 6,
In the microcrack formation step, the mechanical stress is formed by heating, characterized in that the microcapsule surface modification method.
According to claim 13,
Wherein the microcrack formation step is heated to a temperature higher than the boiling point of the first reactant molecule and lower than the boiling point of the continuous phase.
According to claim 6,
In the microcrack formation step, the microcrack is formed in the polymer shell, and the first reaction molecule flows out through the microcrack at the same time.
A microcapsule manufactured by the method of modifying the surface of a microcapsule according to any one of claims 1 to 15.
According to claim 16,
The microcapsule
core material;
A polymer shell surrounding the core material and having microcracks formed thereon;
A microcapsule comprising a surface modification layer formed on the surface of the polymer shell and functioning as a specific functional group.
An adsorbent comprising the microcapsules of claim 16.
A microreactor comprising the microcapsule of claim 16.

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