Composite polydopamine aromatic microcapsule and preparation method thereof

Abstract

The application discloses a composite polydopamine aromatic microcapsule and a preparation method thereof. The core material of the composite polydopamine aromatic microcapsule is aromatic oil, which is prepared by the following steps: cellulose nanocrystal (CNC) is used to encapsulate aromatic compounds to prepare a Pickering emulsion, polyphenol compounds are deposited outside the emulsion droplets to form an elastic interfacial film, and polydopamine is coated on the outermost layer. The composite polydopamine aromatic microcapsule can realize mechanical stimulation response release, and can significantly improve the utilization rate of the aromatic oil. The preparation method is simple, the reaction condition is mild, all the raw materials are biodegradable substances, the method meets the green and environmental protection requirements, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of daily chemical technology, and relates to a composite polydopamine aromatic microcapsule and a preparation method thereof, in particular to a composite polydopamine aromatic microcapsule and a preparation method thereof, which are simple and feasible in preparation process, good in adhesion performance, good in mechanical performance and controllable. BACKGROUND

[0002] Perfume and essence are widely used in many industries due to their unique fragrance characteristics and multiple effects, such as refreshing, antibacterial and antiseptic. However, due to its strong volatility and poor stability, especially under high temperature and light conditions, it is easy to cause oxidation reaction, which limits its application effect. To solve this problem, microcapsule technology is introduced to encapsulate perfume and essence. Through microencapsulation, not only the stability of perfume and essence can be significantly improved, but also the release can be precisely controlled, thereby improving its use efficiency and economic value.

[0003] Aromatic microcapsules are increasingly widely used in textiles, but due to their insufficient adhesion on the surface of the fabric, their performance is limited. The excellent adhesion performance of polydopamine provides a good solution for preparing aromatic microcapsules with high adhesion. For example, CN 202310964066.1 proposes a method for preparing polydopamine microcapsules using a composite template. Although it can achieve effective encapsulation and controlled release of the target substance, the process is complex and has many limitations, requiring multiple steps, including template selection and pretreatment, control of polymerization reaction, and removal of the final template, which may affect the quality and performance of the microcapsules.

[0004] Compared with the traditional complex template method for preparing microcapsules, the method of in-situ deposition of polydopamine in emulsion can realize one-step formation of microcapsules, greatly simplifying the preparation process and reducing production costs. However, the polydopamine microcapsules prepared by this method often have weak mechanical properties.

[0005] Therefore, a polydopamine microcapsule with simple preparation process and good mechanical properties is of great practical significance. SUMMARY

[0006] Due to the above-mentioned defects of the prior art, the present application provides a polydopamine microcapsule with simple preparation process and good mechanical properties, specifically a composite polydopamine aromatic microcapsule and a preparation method thereof, which are simple and feasible in preparation process, good in adhesion performance, good in mechanical performance and controllable. The present application can be applied in daily chemical, textile, agricultural and other fields, and overcomes the defects that polydopamine microcapsules cannot achieve simple preparation process and good mechanical properties at the same time.

[0007] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] A composite polydopamine fragrance microcapsule, the core material of the composite polydopamine fragrance microcapsule is fragrance oil, which is prepared by encapsulating fragrance compounds with CNC (cellulose nanocrystal) to prepare a Pickering emulsion, then depositing polyphenol compounds on the outside of the emulsion droplets to form a film, and finally coating polydopamine on the outermost layer.

[0009] The Pickering emulsion is obtained by self-assembly of CNC (cellulose nanocrystal) and amino-functionalized polymer ligands at the oil-water interface, the surface of the emulsion droplets sequentially adsorbs polyphenol compounds to form an elastic interfacial film, and the polydopamine layer is formed by in-situ deposition of dopamine (dopamine monomers are oxidized and polymerized to form polydopamine at the outermost layer of the emulsion droplets), thereby obtaining a microcapsule with high adhesion and excellent mechanical properties.

[0010] The composite polydopamine fragrance microcapsule of the present application is prepared from CNC (cellulose nanocrystal), polyphenol substances and dopamine and other bio-based materials, which not only enhances the biocompatibility and biodegradability of the microcapsule, but also improves the preparation method by combining tannic acid and dopamine, further improves the stability, adhesion and mechanical strength of the microcapsule, and widens its application scenarios.

[0011] As a preferred technical solution:

[0012] The composite polydopamine fragrance microcapsule as described above, wherein the fragrance oil is selected from one or more of limonene, linalool and cinnamaldehyde;

[0013] The polyphenol compound is selected from one or more of tannic acid, anthocyanin, resveratrol and quercetin.

[0014] In addition, the present application also provides a method for preparing the composite polydopamine fragrance microcapsule as described above, comprising the following steps:

[0015] S1, dispersing CNC (cellulose nanocrystal) in deionized water to obtain an aqueous phase A;

[0016] S2, dissolving the amino-functionalized polymer ligand and the fragrance fixative in the fragrance oil to obtain an oil phase B;

[0017] S3, mixing the oil phase B and the aqueous phase A according to the proportion, and forming a uniform oil-in-water emulsion by high-speed shearing;

[0018] S4, adding a polyphenol compound acidic aqueous solution to the oil-in-water emulsion obtained in S3, and oscillating or stirring for a certain time to obtain a composite emulsion, so that the polyphenol substance is adsorbed on the emulsion interface;

[0019] S5, adding a dopamine hydrochloride aqueous solution into the composite emulsion obtained in S4, adjusting the solution to be alkaline, stirring for a certain time, and obtaining a composite polydopamine aromatic microcapsule suspension;

[0020] S6, performing post-treatment, and obtaining the composite polydopamine aromatic microcapsule.

[0021] The formation mechanism of the composite polydopamine aromatic microcapsule is as follows:

[0022] First, the negatively charged CNC and the positively charged amino-functionalized polymer ligand are self-assembled at the oil-water interface through electrostatic interaction to form a stable emulsion. Then, the polyphenol substance is added to the emulsion, and the catechol structure can effectively adsorb to the surface of the emulsion droplets, thereby forming an elastic interfacial film to enhance the strength of the droplet interface. Finally, dopamine monomers undergo oxidative self-polymerization at the outermost layer of the emulsion droplets to generate microcapsules with high adhesion and excellent mechanical properties, thereby successfully embedding the aromatic substances.

[0023] The above preparation method has the characteristics of simplicity and efficiency, simplifies the process flow, and has mild reaction conditions, which is suitable for large-scale production. The composite shell of the microcapsule not only has good biocompatibility and superior adhesion performance, but also can adjust the mechanical properties of the microcapsule according to the needs of the application scene. Specifically, the mechanical properties of the microcapsule can be effectively adjusted by controlling the concentration of the amino-functionalized polymer ligand, the concentration of the polyphenol compound and its deposition time, the concentration of dopamine hydrochloride and its polymerization time, etc. This adjustment mechanism realizes the mechanical stimulus response release of the microcapsule in different application scenarios, thereby greatly improving the utilization rate of the fragrance oil and having good application prospects.

[0024] As a preferred technical solution:

[0025] The method as described above, the amino-functionalized polymer ligand is selected from one or more of NH2-PDMS-NH2, POSS-NH2 and PS-NH2;

[0026] The fragrance fixative is diethyl phthalate.

[0027] The method as described above, the pH of the solution is adjusted by adding Tris to the solution.

[0028] The method as described above, the mass fraction of CNC in the aqueous phase A is 0.5-6 wt%;

[0029] The mass concentration of the amino-functionalized polymer ligand in the oil phase B is 0.1-20 mg / mL, and the volume fraction of the fragrance fixative in the oil phase B is 0.01-50%;

[0030] The mass concentration of the polyphenol compound in the acidic aqueous solution of the polyphenol compound is 0.01-10 mg / mL.

[0031] The mass concentration of the dopamine hydrochloride in the aqueous solution of the dopamine hydrochloride is 5-30 mg / mL.

[0032] In S3 of the method, the volume ratio of the oil phase B to the aqueous phase A is 1:9-4:6.

[0033] The shear rate of the high-speed shearing is 6k-21k rpm, and the shearing time is 1-10 min.

[0034] In S4 of the method, the pH of the acidic aqueous solution of the polyphenol compound is 3-6, and the oscillation or stirring time is 2-720 min.

[0035] In S5, the basic pH is 8-9, the stirring rate of the stirring is 200-800 r / min, and the stirring reaction time is 12-36 h. The process does not need heating and is not sealed.

[0036] In the method, the post-treatment is to separate the microcapsules from the mixed reaction solution by using a centrifuge, filter the microcapsules by using filter cloth, wash the microcapsules with deionized water until the solution is colorless and clear, and dry the microcapsules to obtain black powder, thereby obtaining the composite polydopamine aromatic microcapsule.

[0037] The above technical solution is only one possible technical solution of the present application, and the protection scope of the present application is not limited to this. Those skilled in the art can reasonably adjust the specific design according to actual needs.

[0038] The above application has the following advantages or beneficial effects:

[0039] (1) The composite polydopamine aromatic microcapsule can microencapsulate various aromatic oils, effectively solves the instability defect of the aromatic oils in the application process, and the adhesion performance is significantly better than that of the traditional microcapsule. This is mainly because the hydrogen bonds and electrostatic interactions are formed between the wall material and the matrix, so that the microcapsule and the matrix can form a firm combination, and the mechanical property is good.

[0040] (2) The preparation method of the composite polydopamine aromatic microcapsule adopts an in-situ deposition method, uses the oxidative self-polymerization reaction of dopamine under alkaline conditions to form a microcapsule wall material, does not need to add monomers, initiators, etc., and does not need to be sealed and heated.

[0041] (3) The preparation method of the composite polydopamine aromatic microcapsule has simple process, high preparation efficiency, mild reaction conditions, and all the raw materials used are biodegradable substances, which is more in line with the requirements of green and environmental protection.

[0042] (4) The preparation method of the composite polydopamine aromatic microcapsule of the present application can effectively control the mechanical properties of the microcapsule by controlling the concentration of the amino-functionalized polymer ligand, the concentration of the polyphenol compound, the deposition time thereof, the concentration of the dopamine hydrochloride, and the polymerization time thereof, and the like. The control mechanism realizes the mechanical stimulation response release of the microcapsule in different application scenarios, thereby greatly improving the utilization rate of the aromatic oil, and has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0043] The present application and its features, shapes and advantages will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings. The same reference numbers in all the drawings indicate the same parts. The drawings are not necessarily drawn to scale, the emphasis being on illustrating the principle of the present application.

[0044] Figure 1 Microscope image (a), scanning electron microscope image (b), and Young's modulus distribution graph (c) of the composite polydopamine aromatic microcapsule prepared for Example 1;

[0045] Figure 2 Microscope image (a), scanning electron microscope image (b), and Young's modulus distribution graph (c) of the composite polydopamine aromatic microcapsule prepared for Example 2;

[0046] Figure 3 Scanning electron microscope images of the composite polydopamine aromatic microcapsule finishing textile prepared for Example 3 under different magnifications;

[0047] Figure 4 Scanning electron microscope images of the composite polydopamine aromatic microcapsule finishing textile prepared for Example 4 under different magnifications. DETAILED DESCRIPTION

[0048] The present application will be further described below in conjunction with the drawings and specific examples, but not as a limitation of the present application.

[0049] Example 1

[0050] A preparation method of a composite polydopamine aromatic microcapsule, comprising the following steps:

[0051] S1, preparation of an aqueous phase: 1.0 wt% of CNC (cellulose nanocrystal) was weighed and added to water, and a ultrasonic cell crusher 600 W was used for ultrasonic treatment for 5 min to make it completely dispersed;

[0052] S2, Preparation of oil phase: 1 mg / mL of NH2-PDMS-NH2 was dissolved in 1.9 mL of a mixture of limonene and 0.1 mL of diethyl phthalate oil, and a magnetic stirrer was used to fully stir and dissolve the solution at a stirring speed of 450 rpm for 1 h;

[0053] S3, The oil phase obtained in S2 was mixed with the water phase obtained in S1 at a ratio of 1 / 9 (v / v), and then the mixture was sheared at 21 k rpm for 3 min to obtain an oil-in-water fragrance emulsion;

[0054] S4, 2 mg / mL of tannic acid was added to the above oil fragrance emulsion, and the pH was adjusted to 6 with Tris powder, and vortexed for 2 min to mix evenly to obtain a composite emulsion.

[0055] S5, 10 mg / mL of dopamine hydrochloride was added to the above composite emulsion, and the pH was adjusted to 8.5 with Tris powder, and polymerized at a stirring speed of 450 rpm for 24 h.

[0056] S6, Post-processing, centrifugal washing and drying to obtain a composite polydopamine fragrance microcapsule.

[0057] The microscope image of the prepared composite polydopamine fragrance microcapsule is shown in Figure 1 (a), the scanning electron microscope image is shown in Figure 1 (b), and the Young's modulus distribution map measured by atomic force microscope is shown in Figure 1 (c). The particle size of the prepared composite polydopamine fragrance microcapsule is about 5-20 μm, and the regional average Young's modulus is 252 MPa.

[0058] Example 2

[0059] A method for preparing a composite polydopamine fragrance microcapsule, which is basically the same as that of Example 1, except that the concentration of NH2-PDMS-NH2 in S2 is 10 mg / mL.

[0060] The microscope image of the prepared composite polydopamine fragrance microcapsule is shown in Figure 2 (a), the scanning electron microscope image is shown in Figure 2 (b), and the Young's modulus distribution map measured by atomic force microscope is shown in Figure 2 (c). The concentration of NH2-PDMS-NH2 is increased to 10 mg / mL, the particle size of the prepared composite polydopamine fragrance microcapsule is about 5-20 μm, and the mechanical property is significantly enhanced, and the regional average Young's modulus can reach 950 MPa. Compared with the microcapsule prepared by using 1 mg / mL of NH2-PDMS-NH2 in Example 1, the mechanical property is enhanced by about 4 times.

[0061] Example 3

[0062] A preparation method of a composite polydopamine aromatic microcapsule, which is basically the same as that of Example 1, except that in S2, the oil phase is composed of 10 mg / mL of POSS-NH2 dissolved in 2 mL of limonene; in S3, the shearing speed is 12 k rpm; in S4, the composite emulsion is prepared by magnetic stirring at 450 rpm for 5.5 h; and in S5, the stirring speed of the polymerization reaction is 200 rpm, and the reaction time is 21 h. The aromatic microcapsule prepared is used to finish a textile, and the adhesion of the microcapsule is observed. The scanning electron microscope images of different magnifications are shown in FIG. 4. It is found that a large number of polydopamine aromatic microcapsules exist on the textile finished with the composite polydopamine aromatic microcapsule. Figure 3

[0063] Example 4

[0064] A preparation method of a composite polydopamine aromatic microcapsule, which is basically the same as that of Example 3, except that in S2, the oil phase is composed of 10 mg / mL of NH2-PDMS-NH2 dissolved in 2 mL of limonene; and in S4, the composite emulsion is prepared by magnetic stirring at 450 rpm for 20 h. The aromatic microcapsule prepared is used to finish a textile, and the adhesion of the microcapsule is observed. The scanning electron microscope images of different magnifications are shown in FIG. 5. It is found that the adhesion effect of the composite polydopamine aromatic microcapsule on the textile is also good. Figure 4

[0065] Example 5

[0066] A preparation method of a composite polydopamine aromatic microcapsule, which is basically the same as that of Example 1, except that in S2, limonene is replaced by cinnamaldehyde.

[0067] Example 6

[0068] A preparation method of a composite polydopamine aromatic microcapsule, which is basically the same as that of Example 1, except that in S3, the volume ratio of the oil phase to the water phase is 2:8.

[0069] Example 7

[0070] A preparation method of a composite polydopamine aromatic microcapsule, which is basically the same as that of Example 1, except that in S5, the concentration of dopamine hydrochloride is 15 mg / mL.

[0071] ​​In summary, the composite polydopamine aromatic microcapsule of the present application can microencapsulate various aromatic oils, effectively solving the instability of aromatic oils in the application process, and its adhesion performance is significantly better than that of traditional microcapsules, which is mainly due to the hydrogen bonds and electrostatic interactions formed between the wall material and the matrix, so that the microcapsule and the matrix can form a firm combination, and at the same time, it has good mechanical properties; the preparation method adopts in-situ deposition method, and uses the oxidative self-polymerization reaction of dopamine under alkaline conditions to form the microcapsule wall material, without adding monomers, initiators and the like, without sealing and heating; the process is simple, the preparation efficiency is high, the reaction conditions are mild, and the raw materials used are all biodegradable substances, which is more in line with the requirements of green environmental protection; by controlling the concentration of the amino-functionalized polymer ligand, the concentration of the polyphenolic compound, the deposition time, the concentration of dopamine hydrochloride and the polymerization time and the like, the mechanical properties of the microcapsule can be effectively controlled, and the control mechanism realizes the mechanical stimulus response release of the microcapsule in different application scenarios, thereby greatly improving the utilization rate of the aromatic oil, and having good application prospect.

[0072] Those skilled in the art should understand that those skilled in the art can realize the variants in combination with the prior art and the above-mentioned embodiments, which are not described here in detail. Such variants do not affect the essential content of the present application, and are not described here in detail.

[0073] The preferred embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and the devices and structures not described in detail should be understood as being implemented in the ordinary way in the art; any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments, without departing from the scope of the technical solutions of the present application, which does not affect the essential content of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the technical solutions of the present application, still belongs to the scope of protection of the technical solutions of the present application.

Claims

1. A composite polydopamine aromatic microcapsule, characterized in that: The core material of the composite polydopamine aromatic microcapsule is aromatic oil, which is prepared by CNC encapsulating aromatic compounds to obtain Pickering emulsion, then depositing polyphenolic compounds on the outside of the emulsion droplets to form a film, and finally coating the outermost layer with polydopamine; the particle size of the composite polydopamine aromatic microcapsule is 5~20μm. Its preparation method includes the following steps: S1. Disperse CNC in deionized water to obtain aqueous phase A; S2. Dissolve the amino-functionalized polymer ligand and fixative in the aromatic oil to obtain oil phase B; The amino-functionalized polymer ligand is selected from one or more of NH2-PDMS-NH2, POSS-NH2 and PS-NH2; the fixative is diethyl phthalate. The mass concentration of the amino-functionalized polymer ligand in the oil phase B is 0.1~20 mg / mL; S3. Mix oil phase B and water phase A in a certain proportion, and form a uniform oil-in-water emulsion by high-speed shearing. S4. Add an acidic aqueous solution of polyphenolic compounds to the oil-in-water emulsion obtained in S3, and shake or stir for a certain period of time to obtain a composite emulsion; wherein the polyphenolic compounds are selected from one or more of tannic acid, anthocyanins, resveratrol and quercetin. S5. Add the hydrochloric acid-dopamine aqueous solution to the composite emulsion obtained in S4, adjust the solution to alkaline, stir and react for a certain time to obtain a composite polydopamine aromatic microcapsule suspension. S6. Post-processing is performed to obtain composite polydopamine aromatic microcapsules.

2. The composite polydopamine aromatic microcapsule according to claim 1, characterized in that, The aromatic oil is selected from one or more of limonene, linalool, and cinnamaldehyde.

3. A method for preparing a composite polydopamine aromatic microcapsule as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Disperse CNC in deionized water to obtain aqueous phase A; S2. Dissolve the amino-functionalized polymer ligand and fixative in the aromatic oil to obtain oil phase B; The amino-functionalized polymer ligand is selected from one or more of NH2-PDMS-NH2, POSS-NH2 and PS-NH2; the fixative is diethyl phthalate. The mass concentration of the amino-functionalized polymer ligand in the oil phase B is 0.1~20 mg / mL; S3. Mix oil phase B and water phase A in a certain proportion, and form a uniform oil-in-water emulsion by high-speed shearing. S4. Add an acidic aqueous solution of polyphenolic compounds to the oil-in-water emulsion obtained in S3, and shake or stir for a certain period of time to obtain a composite emulsion; wherein the polyphenolic compounds are selected from one or more of tannic acid, anthocyanins, resveratrol and quercetin. S5. Add the hydrochloric acid-dopamine aqueous solution to the composite emulsion obtained in S4, adjust the solution to alkaline, stir and react for a certain time to obtain a composite polydopamine aromatic microcapsule suspension. S6. Post-processing is performed to obtain composite polydopamine aromatic microcapsules.

4. The method according to claim 3, characterized in that, The pH of the solution was adjusted by adding tris(hydroxymethyl)aminomethane to the solution.

5. The method according to claim 3, characterized in that, The mass fraction of CNC in the aqueous phase A is 0.5~6wt%; The volume fraction of fixative in oil phase B is 0.01~50%; The mass concentration of the polyphenolic compound in the acidic aqueous solution is 0.01~10 mg / mL; The mass concentration of dopamine hydrochloride in the aqueous solution of dopamine hydrochloride is 5~30 mg / mL.

6. The method according to claim 5, characterized in that, In S3, the volume ratio of oil phase B to water phase A is 1:9 to 4:6; The high-speed shearing has a shearing rate of 6k ~ 21k rpm and a shearing duration of 1 ~ 10 min.

7. The method according to claim 5, characterized in that, In S4, the pH of the acidic aqueous solution of the polyphenol compound is 3-6, and the shaking or stirring time is 2-720 min; In S5, the alkaline pH is 8-9, the stirring rate is 200-800 r / min, and the stirring reaction time is 12-36 h.

8. The method according to claim 3, characterized in that, The post-processing involves using a centrifuge to separate the microcapsules from the mixed reaction solution, filtering with a filter cloth, washing with deionized water until the solution is colorless and clear, and drying to obtain a black powder, which is the composite polydopamine aromatic microcapsules.

Images