A melanin photo-thermal coating material, and a preparation method and application thereof

Abstract

The application discloses a melanin photo-thermal coating material and a preparation method and application thereof, and belongs to the technical field of artificial melanin materials. The preparation method comprises the following steps: dissolving dopamine and p-phenylene diisocyanate in a good solvent, and stirring at room temperature for more than 24 hours to obtain the melanin photo-thermal coating material. The preparation method is based on the controllable alternating copolymerization of hydroxyl-isocyanate group click chemistry to construct a donor-acceptor pair structure in a PDA microstructure, thereby effectively avoiding the problems existing in free radical polymerization, realizing controllable preparation of a PDA melanin coating with good normalized physical properties, and improving the stability of the PDA melanin coating in different solvents, so that the PDA melanin coating can better meet the photo-thermal conversion application of various solvent systems.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of artificial melanin materials, and particularly relates to a melanin photo-thermal coating material and a preparation method and application thereof. BACKGROUND

[0002] As the most typical synthetic melanin polymer, polydopamine (PDA) has functions such as ultraviolet resistance, metal chelation, free radical scavenging and surface temperature regulation, and can be widely applied to ultraviolet shielding, photo-thermal surface modification and other aspects. However, due to the wide range of attenuated absorption of PDA-based melanin in the visible light region, the development of PDA-based melanin photo-thermal materials is limited. Therefore, it is necessary to improve the light absorption and photo-thermal conversion performance of PDA-based melanin photo-thermal materials.

[0003] Building an electron donor-acceptor pair structure is an effective method for adjusting the absorption spectrum. For example, the prior art discloses that PDA nanoparticles (NPs) with adjustable light absorption characteristics are prepared by directly copolymerizing 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and dopamine in an aqueous solution, so as to realize enhanced light absorption and excellent photo-thermal efficiency in a wide spectrum.

[0004] However, the copolymerization of TEMPO and dopamine described above is nitroxyl radical polymerization, which has the following defects: first, nitroxyl radical polymerization is easy to cause confusion of the microstructure of PDA, so that a large number of defects are generated in the macromolecular structure of PDA, which is not conducive to the photo-thermal performance; second, the reaction controllability is poor, making it difficult to control the structure of the product, increasing the difficulty of designing the electron donor-acceptor pair structure, and limiting the adjustment of the photo-thermal performance. SUMMARY

[0005] The application discloses a melanin photo-thermal coating material and a preparation method and application thereof, aiming to solve the technical problems existing in the construction of an electron donor-acceptor pair structure based on free radical polymerization.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the application provides a preparation method of a melanin photo-thermal coating material. The preparation method of the application comprises:

[0007] Dissolving dopamine and p-phenylene diisocyanate in a good solvent, stirring at room temperature for more than 24 hours to obtain a melanin photo-thermal coating material.

[0008] In some embodiments, the molar ratio of dopamine to p-phenylene diisocyanate is 1:1.

[0009] In some embodiments, the concentration of dopamine and p-phenylene diisocyanate in the good solvent is 0.01-0.2 mmol / mL.

[0010] In some embodiments, the good solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile.

[0011] The second aspect of the present application provides a melanin photo-thermal coating material prepared according to the preparation method of the present application.

[0012] The third aspect of the present application provides an application of the melanin photo-thermal coating material prepared by the present application to preparing a photo-thermal coating.

[0013] In some embodiments, the preparation of the photo-thermal coating comprises:

[0014] The good solvent is added to the melanin photo-thermal coating material to dilute the melanin photo-thermal coating material, to obtain a melanin photo-thermal coating configuration liquid.

[0015] In some embodiments, the preparation of the photo-thermal coating further comprises:

[0016] The melanin photo-thermal coating configuration liquid is coated on a flexible substrate.

[0017] In some embodiments, the concentration of the melanin photo-thermal coating configuration liquid is 0.0025-0.01 mmol / mL.

[0018] In some embodiments, the concentration of the melanin photo-thermal coating configuration liquid is 0.01 mmol / mL.

[0019] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application at least include:

[0020] The preparation method provided by the first aspect of the present application rationally analyzes the molecular structure from a chemical perspective, and creatively proposes that the PDA melanin monomer and p-phenylene diisocyanate undergo room temperature stirring in a good solvent, so as to realize controllable alternating copolymerization based on hydroxyl-isocyanate group click chemistry, so as to achieve efficient, stable and controllable construction of the donor-acceptor pair structure in the PDA microstructure. Not only can the problem of PDA microstructure disorder caused by free radical polymerization be effectively avoided, but also the controllable preparation of the PDA melanin coating with good normalized physical properties can be realized. Moreover, the stability of the PDA melanin coating in different solvents is improved, so that it can better meet the photo-thermal conversion application of various solvent systems. At the same time, the PDA melanin coating material prepared by the present application has good color display effect and light absorption capacity, so that the photo-thermal conversion and other applications can be efficiently realized. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0022] Figure 1 Optical photos of DA-PDI, DA-HDI and DA-IPDI with different concentrations provided by the embodiments of the present application;

[0023] Figure 2 SEM photos of DA-PDI-0.05a provided by the embodiments of the present application;

[0024] Figure 3 Element distribution photos of DA-PDI-0.05a provided by the embodiments of the present application;

[0025] Figure 4 X-ray photoelectron spectroscopy of DA-PDI-0.05a provided by the embodiments of the present application;

[0026] Figure 5 Solvent stability comparison chart of DA-PDI-0.05a provided by the embodiments of the present application;

[0027] Figure 6 UV absorption spectrum of DA-PDI, DA-HDI and DA-IPDI with the same concentration provided by the embodiments of the present application;

[0028] Figure 7 Electronic band gap result comparison chart of DA-PDI, DA-HDI and DA-IPDI with the same concentration provided by the embodiments of the present application;

[0029] Figure 8 Optical thermal performance conversion test chart of DA-PDI with different concentrations provided by the embodiments of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0031] In the following description of the embodiments, the term "and / or" is used to describe the association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the cases of A existing alone, B existing alone and A and B existing simultaneously. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0032] In the following description of the embodiments, the term "at least one" means one or more, and "multiple" means two or more. "At least one of the following (one)" or similar expressions means any combination of these items, including any combination of single (one) or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can represent a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b and c can be single or multiple.

[0033] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0034] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of the serial numbers does not mean the order of execution, and some or all steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0035] Those skilled in the art should understand that in the embodiments of the present application, the numerical range should be understood as also specifically disclosing each intermediate value between the upper limit and the lower limit of the range. Each smaller range between any stated value or stated range of values and any other stated value or stated range of values within the stated range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0036] Unless otherwise specified, the technical / scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present application. All documents mentioned in the specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of conflict between the content of the specification and any incorporated document, the content of the specification shall prevail.

[0037] In a first aspect, the embodiments of the present application provide a preparation method of a melanin photo-thermal coating material, which preferably comprises the following steps:

[0038] Dopamine and p-phenylene diisocyanate are dissolved in a good solvent, and stirred at room temperature for more than 24 hours to obtain the melanin photo-thermal coating material.

[0039] It should be noted that the embodiments of the present application do not limit the specific operation of the room temperature stirring, and those skilled in the art can operate according to the conventional experimental requirements; at the same time, the embodiments of the present application do not limit the specific stirring time, as long as it is more than 24 hours.

[0040] It should be noted that the embodiments of the present application do not particularly limit the specific source of dopamine and p-phenylene diisocyanate, which can be directly obtained by market purchase or synthesized by the laboratory itself. For example, the embodiments of the present application obtain dopamine (98.0%) (Shanghai Anjiaji Chemical Co., Ltd.) and diisocyanate (Araladin Reagent (Shanghai) Co., Ltd.) respectively through market purchase.

[0041] The embodiments of the present application creatively select p-phenylene diisocyanate and PDA melanin monomers to undergo room temperature stirring treatment in a good solvent, which realizes the alternating copolymerization based on hydroxyl-isocyanate group click chemistry, so as to efficiently, stably and controllably construct the donor-acceptor pair structure in the PDA microstructure, which not only effectively avoids the problem of PDA microstructure confusion caused by free radical polymerization, realizes the controllable preparation of PDA melanin coating with good normalized performance, but also improves the stability of PDA melanin coating in different solvents, so that it can better meet the photo-thermal conversion application of various solvent systems; at the same time, the PDA melanin coating material prepared by the present application has good color display effect and light absorption capacity, thereby solving the problem of light absorption limitation of PDA melanin polymer.

[0042] In some preparation embodiments, the molar ratio of dopamine to p-phenylene diisocyanate is preferably 1:1, so as to improve the utilization rate of dopamine and p-phenylene diisocyanate, avoid the influence of unreacted materials on the purity of PDA melanin photo-thermal coating material, and omit the separation and treatment process of unreacted dopamine or p-phenylene diisocyanate.

[0043] In some preparation embodiments, the concentration of the dopamine and the p-phenylene diisocyanate in the good solvent is 0.01-0.2 mmol / mL, for example, the concentration of the dopamine and the p-phenylene diisocyanate in the good solvent is 0.01 mmol / mL, 0.05 mmol / mL, 0.1 mmol / mL and 0.2 mmol / mL or any one in the range. In the present application, by selecting the material concentration described above, the low concentration range can clearly reflect the photo-thermal performance of the material, thereby effectively regulating the structure of the dopamine and the p-phenylene diisocyanate.

[0044] In some preparation embodiments, the good solvent is preferably one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF) or acetonitrile. Among them, the three kinds of organic solvents have good solubility, which can ensure the complete dissolution of dopamine and p-phenylene diisocyanate and meet the actual application requirements of preparing photo-thermal conversion coating.

[0045] In a second aspect, the present application provides a melanin photo-thermal coating material prepared by the preparation method of the present application. In the present application, the donor-acceptor pair structure in the PDA microstructure is formed by click chemistry, so the melanin photo-thermal coating material has good ultraviolet absorption capacity and enhanced light stability.

[0046] In a third aspect, the present application provides the application of the melanin photo-thermal coating material of the present application in preparing photo-thermal coating. In view of the good ultraviolet absorption capacity and enhanced light stability of the melanin photo-thermal coating material of the present application, the melanin photo-thermal coating material can efficiently and durably provide photo-thermal conversion application when used in preparing photo-thermal coating.

[0047] In some application embodiments, the preparation of the photo-thermal coating preferably comprises:

[0048] The melanin photo-thermal coating material is diluted with the good solvent to obtain a melanin photo-thermal coating configuration liquid. In the present application, the flowability of the configuration liquid is effectively regulated by diluting the melanin photo-thermal coating material, thereby ensuring the uniformity of the formed photo-thermal coating and making the color uniformity good.

[0049] It should be noted that the good solvent used for dilution is the same as the good solvent used for preparing the melanin photo-thermal coating material. For example, when dimethyl sulfoxide is used as the good solvent for preparing the melanin photo-thermal coating material, the good solvent used for dilution is also dimethyl sulfoxide; when N,N-dimethylformamide is used as the good solvent for preparing the melanin photo-thermal coating material, the good solvent used for dilution is also N,N-dimethylformamide; when acetonitrile is used as the good solvent for preparing the melanin photo-thermal coating material, the good solvent used for dilution is also acetonitrile.

[0050] In some application embodiments, the preparing the photothermal coating preferably further comprises:

[0051] The melanin photothermal coating configuration liquid is uniformly coated on a flexible substrate including silk, cotton cloth, etc. Among them, the flexible photothermal conversion coating is prepared by uniformly coating the melanin photothermal coating configuration liquid on the flexible substrate such as silk, cotton cloth, etc. in the application embodiment, so that a wide range of photothermal conversion applications can be met.

[0052] In some application embodiments, the concentration of the melanin photothermal coating configuration liquid is preferably 0.0025-0.01 mmol / mL, for example, 0.0025 mmol / mL, 0.005 mmol / mL, 0.01 mmol / mL or any one in the range. Among them, the application embodiment is diluted to the concentration of the configuration liquid, so as to effectively reflect the photothermal performance of the material, so as to effectively regulate the structure of dopamine and p-phenylene diisocyanate.

[0053] In some application embodiments, the concentration of the melanin photothermal coating configuration liquid is more preferably 0.01 mmol / mL, so as to further clearly reflect the photothermal performance of the material.

[0054] The technical solutions of the application will be further described below in combination with specific embodiments.

[0055] Embodiment 1

[0056] The embodiment provides a preparation method of a melanin photothermal coating material (DA-PDI-0.05a), comprising the following steps:

[0057] 0.5 mmol dopamine and 0.5 mmol p-phenylene diisocyanate are dissolved in 10 mL DMSO, and stirring is maintained at room temperature for 24 hours, to obtain DA-PDI-0.05a.

[0058] Embodiment 2

[0059] The embodiment provides a preparation method of a melanin photothermal coating material (DA-PDI-0.1a), comprising the following steps:

[0060] 1.0 mmol dopamine and 1.0 mmol p-phenylene diisocyanate are dissolved in 10 mL DMSO, and stirring is maintained at room temperature for 24 hours, to obtain DA-PDI-0.1a.

[0061] Embodiment 3

[0062] The embodiment provides a preparation method of a melanin photothermal coating material (DA-PDI-0.2a), comprising the following steps:

[0063] Dopamine 2.0 mmol and p-phenylene diisocyanate 2.0 mmol were co-dissolved in 10 mL DMSO, and maintained stirring at room temperature for 24 hours to obtain DA-PDI-0.2a.

[0064] Example 4

[0065] The present example provides a preparation method of a melanin photo-thermal coating material (DA-PDI-0.05b), comprising the following steps:

[0066] Dopamine 0.5 mmol and p-phenylene diisocyanate 0.5 mmol were co-dissolved in 10 mL DMF, and maintained stirring at room temperature for 24 hours to obtain DA-PDI-0.05b.

[0067] Example 5

[0068] The present example provides a preparation method of a melanin photo-thermal coating material (DA-PDI-0.05c), comprising the following steps:

[0069] Dopamine 0.5 mmol and p-phenylene diisocyanate 0.5 mmol were co-dissolved in 10 mL acetonitrile, and maintained stirring at room temperature for 24 hours to obtain DA-PDI-0.05c.

[0070] To illustrate the actual effect of the preparation method of the present application, Comparative Examples 1 and 2 are provided below.

[0071] Comparative Example 1

[0072] Comparative Example 1 prepared DA-HDI of different concentrations, which is different from Examples 1-3 in that hexamethylene diisocyanate (HDI) is used to replace p-phenylene diisocyanate, and the rest is the same as Example 1, and the obtained product is denoted as DA-HDI.

[0073] Comparative Example 2

[0074] Comparative Example 1 prepared DA-IPDI of different concentrations, which is different from Example 1 in that isophorone diisocyanate (IPDI) is used to replace p-phenylene diisocyanate, and the rest is the same as Example 1, and the obtained product is denoted as DA-IPDI.

[0075] Among them, the DA-PDI of different concentrations prepared by Examples 1-3, the DA-HDI of different concentrations prepared by Comparative Example 1, and the DA-IPDI of different concentrations prepared by Comparative Example 1 are physically characterized, and the results are shown in Table 1. Figure 1 As shown in Table 1, the DA-PDI of different concentrations prepared by Examples 1-3, the DA-HDI of different concentrations prepared by Comparative Example 1, and the DA-IPDI of different concentrations prepared by Comparative Example 1 are physically characterized, and the results are shown in Table 1. Figure 1 Table 1: Optical photographs of DA-PDI, DA-HDI and DA-IPDI of different concentrations.

[0076] According toFigure 1 It can be seen that different concentrations of DA-HDI and DA-IPDI coating on glass form obvious brown coating, and different concentrations of DA-PDI coating on glass form significant black coating, which shows that p-phenylene diisocyanate has specificity for adding PDA melanin monomer.

[0077] Next, the structure and performance of the DA-PDI-0.05a sample solution will be characterized and tested.

[0078] 1. Scanning electron microscope characterization

[0079] The DA-PDI-0.05a sample solution was spin-coated on the surface of a smooth silicon wafer, dried, and then gold sprayed, and then characterized by scanning electron microscopy and element distribution, respectively, and the results are shown in Figures 2-3 , wherein Figure 2 is the SEM image of DA-PDI-0.05a; Figure 3 is the element distribution map of DA-PDI-0.05a.

[0080] According to Figures 2-3 , it can be seen that DA-PDI-0.05a is a good colloidal morphology; DA-PDI-0.05a contains elements C, N, and O, and the elements C, N, and O are uniformly distributed.

[0081] 2. X-ray photoelectron spectroscopy characterization

[0082] The chemical bonds of the DA-PDI-0.05a sample were characterized by X-ray photoelectron spectroscopy, and the results are shown in Figure 4 , wherein Figure 4 is the X-ray photoelectron spectrum of DA-PDI-0.05a.

[0083] According to Figure 4 , it can be seen that there is a clear peak of -NH- / -NH2 in the N1s spectrum of DA-PDI-0.05a, which represents the chemical history of the reaction between isocyanate groups and dopamine hydroxyl groups.

[0084] 3. Solvent resistance test

[0085] After the DA-PDI-0.05a sample solution was coated on silk, it was immersed in water, PBS buffer, hydrochloric acid solution, methanol, acetonitrile, and dichloromethane for 12 hours, respectively, and the results are shown in Figure 5 , wherein Figure 5 is the solvent stability comparison chart of DA-PDI-0.05a.

[0086] According to Figure 5 , it can be seen that DA-PDI-0.05a has good stability in different solvents.

[0087] 4. Light absorption capacity test

[0088] The same concentrations (0.05 mmol / mL) of DA-PDI, DA-HDI, and DA-IPDI prepared in Examples 1 and Comparative Examples 1-2 were diluted to 0.01 mmol / mL DMSO solutions of the copolymers. The UV absorption of the samples in the wavelength range of 300–800 nm (slit width 2 nm) was measured using a UV-Vis spectrophotometer. The results are as follows. Figure 6 As shown. Among them, Figure 6 The images show the UV absorption spectra of DA-PDI, DA-HDI, and DA-IPDI at the same concentration.

[0089] according to Figure 6 It can be seen that DA-PDI, DA-HDI and DA-IPDI all have good absorption in the visible light region. Among them, DA-PDI has stronger light absorption capacity than DA-HDI and DA-IPDI.

[0090] 5. Electron bandgap test results

[0091] In this embodiment, the electronic energy levels of DA-PDI, DA-HDI, and DA-IPDI at the same concentration (0.05 mmol / mL) were calculated using density functional theory (DFT), and the results are as follows: Figure 7 As shown. Among them, Figure 7 Comparison of electronic band gap results for DA-PDI, DA-HDI, and DA-IPDI at the same concentration (0.05 mmol / mL).

[0092] according to Figure 7 It can be seen that the calculated electronic band gap results for DA-PDI, DA-HDI, and DA-IPDI of the same concentration correspond perfectly with the optical absorption results. The smaller the band gap, the stronger the optical absorption in the visible light region, and vice versa. The results show that DA-PDI has the smallest electronic band gap and the strongest optical absorption performance.

[0093] 6. Photothermal conversion diagram

[0094] After diluting 0.05 mmol / mL DA-PDI to 0.005 mmol / mL, 0.0025 mmol / mL, and 0.01 mmol / mL, respectively, 1 mL of each solution was transferred to a quartz cuvette at room temperature and subjected to a nanolaser (2.0 W·cm⁻¹). -2 Irradiate for 10 minutes. Then turn off the laser and allow the solution to cool gradually at room temperature. To record temperature changes, a thermocouple probe (accurate to 0.1°C) is placed vertically as close to the laser as possible, but without touching it. A digital thermometer connected to the thermocouple probe is used to record the temperature every 10 seconds. The results are as follows:Figure 8 The light-to-heat conversion test results of different concentrations of DA-PDI are shown. Among them, Figure 8 The light-to-heat conversion test results of different concentrations of DA-PDI are shown. Among them,

[0095] According to Figure 8 It can be seen that the temperature of different concentrations of DA-PDI increased by 8.8℃, 13.1℃ and 25.5℃ after 10 minutes of irradiation, while the temperature of blank DMSO did not change, indicating that DA-PDI has good light-to-heat conversion efficiency.

[0096] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be mutually referred to, and each embodiment focuses on the difference from other embodiments.

[0097] The above examples are only used to illustrate the technical solutions of the present application, and are not limited to the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A method for preparing a melanin photothermal coating material, characterized by, The method comprises the following steps: Dopamine and p-phenylene diisocyanate are dissolved in a good solvent, stirred at room temperature for 24 hours to obtain a melanin photo-thermal coating material; The molar ratio of dopamine to p-phenylene diisocyanate is 1:1, and the concentration of dopamine and p-phenylene diisocyanate in the good solvent is 0.01-0.2 mmol / mL.

2. The production method according to claim 1, characterized by, The good solvent is one of dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile.

3. A melanin photothermal coating material, characterized by, Prepared by the preparation method of claim 1 or 2.

4. The application of the melanin photo-thermal coating material prepared by the preparation method of claim 1 or 2 or the melanin photo-thermal coating material of claim 3 in preparing a photo-thermal coating.

5. Use according to claim 4, characterized in that, Comprise: The melanin photo-thermal coating material is diluted by adding the good solvent to obtain a melanin photo-thermal coating configuration liquid.

6. Use according to claim 5, characterized in that, Further comprise: The melanin photo-thermal coating configuration liquid is coated on a flexible substrate.

7. Use according to claim 5 or 6, characterized in that, The molar concentration of the melanin photo-thermal coating configuration liquid is 0.0025-0.01 mmol / mL.

8. Use according to claim 7, characterized in that, The molar concentration of the melanin photo-thermal coating configuration liquid is 0.01 mmol / mL.

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