Photo-thermal material, preparation method and application
By preparing micron-sized organic eutectic materials under surfactant protection and loading them onto polypropylene fiber films, the problem of morphology control of organic eutectic materials was solved, achieving broad-spectrum absorption and photothermal bactericidal properties, as well as unidirectional wetting ability and highly efficient antibacterial effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-03-13
AI Technical Summary
The morphology of existing organic eutectic materials is difficult to control during the preparation process, which affects the spectral absorption capacity of the materials and limits their applications.
Micron-sized organic eutectic materials were prepared by using electron donors and electron acceptors under the protection of surfactants and through ultrasound-assisted reaction. These materials were then loaded onto polypropylene fiber films to form photothermal conversion films.
It achieves broad-spectrum absorption performance, possesses unidirectional wetting ability and excellent photothermal sterilization performance, and can effectively destroy bacterial cell structure under sunlight irradiation to achieve antibacterial and disinfection effects, with a bacteriostatic rate of over 99%.
Smart Images
Figure CN121652142A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of high light utilization efficiency and heat absorber coating materials, specifically to a photothermal material, its preparation method, and its application. Background Technology
[0002] Photothermal conversion films are thin-film materials that can convert light energy into heat energy. They absorb the radiant energy from a light source and convert it into heat for utilization, making them valuable in fields such as solar energy conversion and photothermal catalysis. Typically, photothermal conversion films consist of a light-absorbing layer, a substrate material, a protective layer, and other functional layers. The light-absorbing layer is the core component, its main function being to absorb light energy and convert it into heat. The light-absorbing layer is generally composed of photothermal conversion materials, such as metal nanoparticles, semiconductor materials, carbon-based materials, and organic conjugated materials. Photothermal materials can achieve light absorption rates exceeding 90% within specific wavelength absorption ranges; however, some photothermal materials have narrow absorption spectra that cannot match solar radiation, leading to wasted light energy. Therefore, developing novel photothermal materials with broad-spectrum absorption and excellent photothermal conversion performance has become a research hotspot in the field of photothermal conversion films.
[0003] Organic eutectic materials are novel crystalline materials with specific structures and properties, formed by the combination of two or more organic molecules in a crystalline state through non-covalent bonds (such as hydrogen bonds, π-π interactions, van der Waals forces, etc.) in a certain stoichiometric ratio. The components are classified as electron donors and electron acceptors based on their electron absorption capabilities. Organic eutectic materials possess advantages such as structural diversity, tunable properties, and simple preparation methods, making them popular among researchers and showing broad application potential in optoelectronics, solar cells, precise drug delivery, and gas storage and separation.
[0004] The preparation of photothermal conversion thin films or coatings using organic eutectic materials shows promising application prospects in solar-driven seawater evaporation. The spectral absorption capacity of organic eutectic materials is largely related to their morphology, and the research on broadband absorption photothermal materials is inseparable from the control of the morphology of organic eutectic materials. Existing preparation methods for organic eutectic materials mostly employ the rapid combination of electron donors and acceptors in organic solvents, which often leads to problems such as excessively fast reaction rates, uncontrollable processes, and large particle sizes in the obtained solid materials, thus limiting the application of organic eutectic materials. Therefore, developing novel preparation methods to control reaction rates and material morphology is of great significance. Summary of the Invention
[0005] The purpose of this invention is to provide a photothermal material, its preparation method, and its application, in order to solve the problem that the morphology of existing organic eutectic materials is difficult to control during the preparation process, which affects the spectral absorption capacity of the materials.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a photothermal material, wherein the photothermal material is an organic eutectic material prepared by electron donor and electron acceptor under the protection of surfactant.
[0007] Furthermore, the electron donor includes tetrathiofulvalene; the electron acceptor includes 7,7,8,8-tetracyano-p-benzodiquinone dimethane; and the solvent for the electron donor and electron acceptor is an organic solvent.
[0008] Furthermore, the surfactant is a nonionic surfactant, including poloxamer, polyvinylpyrrolidone, polyethylene glycol octylphenyl ether, and Tween-20; the solvent for the nonionic surfactant is water.
[0009] A method for preparing a photothermal material includes the following steps: S1. Mix the electron donor with the surfactant to obtain a mixed solution; S2. Add the electron acceptor to the S1 mixed solution and react under ultrasonic conditions.
[0010] Further, in S1, the electron donor includes tetrathiofulvalene, and the surfactant includes poloxamer, polyvinylpyrrolidone, polyethylene glycol octylphenyl ether, and Tween-20; the organic solvent solution of tetrathiofulvalene and the aqueous solution of the surfactant are thoroughly mixed; the organic solvent includes acetone, tetrahydrofuran, methanol, and dichloromethane.
[0011] Furthermore, in S2, the electron acceptor is 7,7,8,8-tetracyano-p-benzodiquinone dimethane; the acetone solution of 7,7,8,8-tetracyano-p-benzodiquinone dimethane is thoroughly mixed with the mixed solution in S1.
[0012] Furthermore, in S2, the frequency of the ultrasonic wave is 20~40kHz, and the intensity is 0.1~1W / cm. 2 The reaction temperature is 20±5℃, and the reaction time is 1~3h.
[0013] Application of photothermal materials as materials for preparing photothermal conversion thin films.
[0014] Furthermore, the photothermal material is loaded onto a substrate material.
[0015] Furthermore, the substrate material includes a polypropylene fiber film.
[0016] The beneficial effects of this invention are: This invention provides a novel water-soluble organic eutectic material (TQM) with broad-spectrum absorption properties. Through the protective effect of surfactants, the morphology of the organic eutectic material is controlled, and it possesses a broad absorption spectrum. This invention utilizes the broad-spectrum absorption organic eutectic material as a photothermal material, loading it onto a polypropylene fiber film to obtain a photothermal conversion film. This photothermal conversion film exhibits good photothermal conversion performance, unidirectional wetting ability, and excellent photothermal sterilization properties under sunlight irradiation.
[0017] The specific technical effects are reflected in the following aspects: 1. This invention utilizes the protective effect of surfactants to disperse the raw materials for preparing organic eutectics in an aqueous solution of surfactants, and the reaction proceeds slowly with the assistance of ultrasound. Due to the protective effect of surfactants, the rate of organic eutectic formation decreases, resulting in a crystalline material with a broad spectrum and a crystal size reduced to the micrometer level, which can be well dispersed in water. Using the organic eutectic material with broad spectral absorption as a photothermal material, the resulting photothermal conversion film exhibits good photothermal conversion performance. 2. Compared with polyacrylamide films without photothermal materials, the hydrophilicity of the polyacrylamide fibers coated with photothermal materials and adhesives in this invention changes, which changes the wetting properties of water on both sides of the polyacrylamide film, giving it the ability to wet liquids in one direction, and providing technical support for applications such as the preparation of smart fabrics and the control of liquid flow. Furthermore, adding unidirectional wetting properties to the photothermal conversion film allows water molecules to flow unidirectionally from the side in contact with water to the evaporation side, preventing steam or condensate from flowing back to the original water side and reducing heat loss. Simultaneously, it concentrates heat on the surface of the photothermal conversion film, causing a rapid increase in local temperature, which more effectively damages bacterial cell membranes or denatures bacterial proteins, leading to bacterial death. It also prevents bacteria and other contaminants from entering the clean area, inhibits the release and diffusion of antibacterial substances, and avoids secondary pollution. 3. The photothermal conversion film of this invention, after absorbing light energy and converting it into heat energy, can destroy the cell structure of bacteria and viruses, inhibit their growth and reproduction, thereby achieving the purpose of antibacterial and disinfection. Among them, the antibacterial rate against Gram-negative and Gram-positive bacteria reaches more than 99%, and has a good photothermal sterilization effect. The antibacterial effect of this invention does not require external energy input, and can achieve sterilization under sunlight, providing a solution for outdoor sterile environments, personal outdoor protection, and antibacterial fabrics. Attached Figure Description
[0018] Figure 1 a is a schematic diagram of TQM morphology control in this invention; Figure 1 b shows the optical images and absorption spectra of TTF, TCNQ, and TQM; Figure 1c shows the SEM images of TQM at different reaction times; Figure 2 These are photographs and corresponding SEM images of a polypropylene film loaded with TQM photothermal material and a blank polypropylene film according to embodiments of the present invention. Figure 3 These are thermal imaging images of the photothermal conversion effect of the photothermal conversion thin film and the blank thin film in the embodiments of the present invention; Figure 4 These are diagrams illustrating the water wetting process of the back and front sides of the photothermal conversion film in an embodiment of the present invention. Figure 5 This is a diagram illustrating the inhibitory effect of the photothermal conversion film on different types of bacteria under sunlight irradiation according to an embodiment of the present invention. Figure 6 a is a schematic diagram of the structure of the photothermal antibacterial mask, an application example of the present invention; 6b is a diagram of the photothermal antibacterial mask worn by volunteers in a laboratory environment; 6c is a diagram of the contamination test of the bacterial aerosol generation device and the photothermal antibacterial mask; 6d is an infrared image of solar radiation on the photothermal antibacterial mask with and without the solar simulator; 6e is a diagram of the survival rate of Escherichia coli and Staphylococcus aureus under different irradiation times evaluated using the typical CFU method; 6f is a summary data diagram of the bacterial survival rate curve; 6g is a comparison diagram of the antibacterial effect after 6 irradiation cycles (30 min each); 6h is a scanning electron microscope image of the photothermal antibacterial mask after spraying Escherichia coli aerosol with and without the solar simulator. Figure 7 a is a schematic diagram of the photothermal antibacterial mask of the present invention in a real scene and its antibacterial process; 7b is a real scene photo of volunteers wearing ordinary surgical masks, silver nanoparticle masks and photothermal antibacterial masks; 7c is the surface temperature change curve of the three types of masks during daily activities; 7d is a comparison of microscopic images of the three types of masks after wearing for 8 hours; 7e is a comparison of the sterilization effect of masks after wearing for 8 hours using the typical CFU method, with bacterial samples taken from the outer surface of the corresponding masks; 7f is a graph of the evaluation results of antibacterial activity. Detailed Implementation
[0019] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.
[0020] The photothermal conversion properties of a material are closely related to its light absorption capacity and photothermal conversion efficiency. Among them, the absorption width of the spectrum is an important indicator for evaluating the light absorption capacity of a material.
[0021] Traditional organic eutectic preparations are mostly carried out in organic phase media. During the formation of organic eutectic, the reaction rate of electron acceptor and electron donor is relatively fast, the reaction process is not easy to control, and the obtained organic eutectic particles are relatively large, which limits the application of organic eutectic materials.
[0022] This invention achieves reaction rate control during the material generation process by protecting electron donor and electron acceptor materials with surfactants, thereby obtaining organic eutectic materials with micron-sized structures; the charge transfer effect between electron donor and electron acceptor is stronger, achieving the purpose of broadening spectral absorption.
[0023] The core of photothermal conversion films lies in photothermal conversion materials. This invention utilizes the protective effect of surfactants to prepare charge-transfer-based organic eutectic materials. The size of the obtained organic eutectic materials is controlled at the micrometer level, and they possess a broad absorption spectrum. This invention uses organic eutectic materials with broad-spectrum absorption as photothermal materials. The organic eutectic materials are mixed with an aqueous solution of PVA, and then uniformly coated onto a polypropylene fiber film to obtain a photothermal conversion film with good photothermal effect and good stability.
[0024] The photothermal conversion film prepared by the present invention exhibits good photothermal conversion effect under sunlight irradiation. At the same time, the photothermal conversion film has unidirectional wetting ability and shows excellent photothermal sterilization performance under sunlight irradiation. It shows great application potential in the fields of photothermal conversion, solar energy utilization, photothermal catalysis and photothermal sterilization.
[0025] Example In this embodiment, the photothermal conversion film consists of two processes: 1. An organic electron donor (tetrathiofulvalene, TTF) and an electron acceptor material (7,7,8,8-tetracyano-p-benzoquinone dimethane, TCNQ) were sequentially dispersed in an aqueous solution of F127 (poloxamer). Under ultrasonic assistance, an organic charge transfer material with broad-spectrum absorption was obtained. 2. Load the prepared organic charge transfer material onto a polypropylene fiber film, adjust the proportion of internal adhesive and other components, and uniformly coat it onto the film using a blade coating method to obtain a functional photothermal conversion film.
[0026] The specific process is as follows: Add 1.0 mL of TTF acetone solution (concentration 0.5 mg / mL) to 18 mL of 0.5% poloxamer (Pluronic F-127) aqueous solution, and mix the two solutions evenly using a vortex mixer to obtain a mixed solution.
[0027] Next, 1.0 mL of TCNQ acetone solution (concentration of 1.0 mg / mL) was quickly added to the above mixed solution, and the mixture was quickly mixed evenly using a vortex mixer. At this time, the solution changed from light green to brownish red, and the mixed reaction solution was obtained.
[0028] The obtained mixed reaction solution was placed in an ultrasonic cleaner (25 kHz), and the water temperature was kept at around 20°C. After reacting under ultrasound for about 1 hour, the precipitate was obtained by centrifugation. The obtained organic charge transfer material (TQM) precipitate was washed twice with water and then redissolved in water for later use.
[0029] Prepare an adhesive solution, such as a polyvinyl alcohol aqueous solution (PVA, 5~15 wt.%), add a lithium chloride aqueous solution (LiCl, 0.08~1 wt.%) to the adhesive solution, dissolve the TQM aqueous solution in the above mixed adhesive solution, and mix evenly using a vortex mixer to obtain a mixed solution.
[0030] The prepared mixed solution is uniformly coated onto a polypropylene fiber film (12.0 cm long and 3.0 cm wide). Care should be taken not to rub the film to break it, and only one side should be coated, leaving the other side blank.
[0031] The uniformly coated film is placed in an oven and dried at 37°C for about 4 hours to obtain the photothermal conversion film of the present invention.
[0032] Organic eutectic materials are generally formed by electron donor and electron acceptor materials under the action of charge transfer effect.
[0033] In this embodiment, using TTF as an electron donor and TCNQ as an electron acceptor, under the protection of a surfactant (0.5% F127), the particle size of the organic eutectic material was successfully controlled at the micrometer level. This was achieved by adjusting the ratio of raw materials in the organic eutectic reaction (TTF:TCNQ = 2:1), the reaction time (20 min), the reaction temperature (20 °C), and the ultrasonic-assisted power (0.6 W / cm²). 2 Further control over the morphology of organic eutectic materials. For example... Figure 1 As shown, the obtained organic eutectic material exhibits a broad absorption spectrum after purification, demonstrating the morphology control capability of the surfactant.
[0034] The obtained 1.5 mL TQM material (400 ug / mL) was doped into 5 mL PVA aqueous solution (10 wt.%), and 0.5 mL lithium chloride aqueous solution (0.25 wt.%) was added and mixed evenly to obtain a mixed solution.
[0035] A polypropylene fiber film with a length of 12.0 cm and a width of 3.0 cm is evenly spread on a platform. 2.0 mL of the above mixed solution is dropped onto the polypropylene fiber film. The solution is evenly coated on the film using a scraper. The film is then placed in an oven and dried at 37°C to obtain the photothermal conversion film (TQM-F) of this invention.
[0036] Fiber membranes loaded with organic eutectic materials and blank controls are shown below. Figure 2As shown, compared to polyacrylamide films without photothermal materials, the surface morphology of the polyacrylamide fibers coated with photothermal materials and adhesives in this invention changes significantly, resulting in changes in the water wetting properties of both sides of the polyacrylamide film, giving it the ability to wet liquids in one direction.
[0037] Generally, applying a hydrophilic coating to the surface of a polypropylene film can alter its wettability. In this embodiment, a mixture of organic eutectic materials is coated on one side of the film, creating a difference in hydrophilicity between the two sides.
[0038] like Figure 4 As shown, since there is no mixed solution loaded on the back of the polypropylene film, it cannot be wetted when the droplet is immersed; while the front of the polypropylene film is coated with a mixed solution of organic eutectic material, and when it comes into contact with the liquid, the droplet is rapidly wetted and diffuses, further proving the unidirectional wetting function of the photothermal conversion film.
[0039] To verify the photothermal conversion properties of the photothermal conversion film, this embodiment places the prepared photothermal conversion film under a solar simulator and exposes it to white light (power 1kW / m²). 2 Thermal imaging is used to record temperature changes.
[0040] The results are as follows Figure 3 As can be seen, compared with the blank polypropylene fiber film, the photothermal conversion film prepared in this embodiment has a better photothermal conversion effect.
[0041] Generally, the antibacterial properties of photothermal conversion films are related to their photothermal conversion efficiency and irradiation time. To verify the antibacterial effect of the photothermal conversion film of this invention, the film was cut into a circle and placed on a culture medium coated with Escherichia coli and Staphylococcus aureus.
[0042] The results are as follows Figure 5 As shown, the diameter of the inhibition zone increases with the extension of the simulated sunlight irradiation time; the diameter of the inhibition zone reaches its maximum after about 15 minutes of irradiation; this demonstrates the universality and effectiveness of the antibacterial effect of the photothermal conversion film.
[0043] This invention can greatly promote the application of photothermal conversion films in photothermal conversion, air purification and biomedicine.
[0044] Application Example 1 Based on the excellent solar thermal evaporation performance and strong antibacterial properties of the photothermal conversion film of this invention, its applicability in different scenarios was investigated. As a proof of concept, a laboratory photothermal antibacterial mask (TQM-M) was designed based on commercial masks to verify its self-protection capabilities in daily life.
[0045] The photothermal conversion film of the embodiment is physically integrated into the three-layer mask structure. Figure 6 a) as a sterilization layer, and worn by volunteers ( Figure 6 b). To verify the solar-powered antibacterial effect in practical applications, bacterial aerosol was sprayed onto the outer layer of the solar-thermal antibacterial mask using a sprayer containing E. coli solution, and then placed under a solar simulator for antibacterial testing. Figure 6 c). Figure 6 Infrared images of d show that the photothermal antibacterial mask has good solar thermal conversion performance. For example... Figure 6 As shown in e and 6f, after 20 minutes of irradiation, the number of colony-forming units (CFU) of *E. coli* and *Staphylococcus aureus* decreased by 99.9%, respectively. Based on this, the antibacterial efficiencies against *E. coli* after 5, 10, 15, and 20 minutes of solar irradiation were calculated to be 63.8%, 21.3%, 10.8%, and 0.1%, respectively. The antibacterial effect against *Staphylococcus aureus* was similar, with corresponding inhibition rates of 72.4%, 44.25%, 8.25%, and 0.1%, respectively. Furthermore, as... Figure 6 As shown in g, a cyclic antibacterial test was conducted on the photothermal antibacterial mask. The results showed that after six cycles, the antibacterial efficiency did not decrease significantly. To investigate the antibacterial mechanism, researchers observed the morphological changes of *Escherichia coli* and *Staphylococcus aureus* under solar radiation. The experiment revealed that bacterial cell membranes showed wrinkles and even ruptures, indicating that the photothermal effect can induce bacterial cell membrane rupture. Figure 6 These results indicate that photothermal antibacterial masks can effectively inactivate bacteria, demonstrating their potential in preventing bacterial infections in wearers.
[0046] As a proof of concept, volunteers were allowed to wear the self-developed laboratory photothermal antibacterial mask in a real-world setting. Figure 7 a) to evaluate its outdoor antipathogenic protection efficacy. For comparison, volunteers also wore commercial surgical masks and silver nanoparticle masks ( Figure 7 b). Subsequently, an in vitro human trial was conducted on a sunny day, using an infrared camera to monitor changes in the surface temperature of the mask. Figure 7 The results showed that during daily activities (such as walking or sitting), the surface temperature of the photothermal antibacterial mask reached approximately 57.1°C, significantly higher than that of ordinary surgical masks and silver nanoparticle masks. To assess the actual protective effect, bacterial cultures were performed on mask residue collected after 8 hours of wear. Figure 7 d). Figure 7 The results clearly show that the number of live bacteria on the photothermal antibacterial mask decreased significantly, with almost no surviving bacteria (>99%). In contrast, the silver nanoparticle mask killed a large number of bacteria, while a large number of bacteria remained surviving on ordinary surgical masks. Figure 7(e and 7f). All results indicate that the laboratory-developed photothermal antibacterial mask is significantly more effective than commercially available masks. Its superior bactericidal properties also suggest broad application prospects as a protective coating. However, due to the solar heating effect, prolonged wear may cause thermal discomfort in the facial and nasal areas, requiring future work to address these issues.
[0047] This invention is not limited to the preferred embodiments described above. Anyone can derive other forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.
Claims
1. A photothermal material, characterized in that: The photothermal material is an organic eutectic material prepared by combining an electron donor and an electron acceptor under the protection of a surfactant.
2. The photothermal material according to claim 1, characterized in that: The electron donor includes tetrathiofulvalene; the electron acceptor includes 7,7,8,8-tetracyano-p-benzodiquinone dimethane; and the solvents for the electron donor and electron acceptor are organic solvents.
3. The photothermal material according to claim 1, characterized in that: The surfactant is a nonionic surfactant, including poloxamer, polyvinylpyrrolidone, polyethylene glycol octylphenyl ether, and Tween-20; the solvent for the nonionic surfactant is water.
4. A method for preparing a photothermal material, characterized in that, Includes the following steps: S1. Mix the electron donor with the surfactant to obtain a mixed solution; S2. Add the electron acceptor to the S1 mixed solution and react under ultrasonic conditions.
5. The method for preparing a photothermal material according to claim 4, characterized in that: In S1, the electron donor includes tetrathiofulvalene, and the surfactant includes poloxamer, polyvinylpyrrolidone, polyethylene glycol octylphenyl ether, and Tween-20; the organic solvent solution of tetrathiofulvalene and the aqueous solution of the surfactant are thoroughly mixed.
6. The method for preparing a photothermal material according to claim 4, characterized in that: In S2, the electron acceptor is 7,7,8,8-tetracyano-p-benzodiquinone dimethane; the acetone solution of 7,7,8,8-tetracyano-p-benzodiquinone dimethane is thoroughly mixed with the mixed solution in S1.
7. The method for preparing a photothermal material according to claim 4, characterized in that: In step S2, the frequency of the ultrasonic wave is 20~40kHz, and the intensity is 0.1~1W / cm. 2 The reaction temperature is 20±5℃, and the reaction time is 1~3h.
8. The application of the photothermal material according to any one of claims 1-7 as a material for preparing photothermal conversion thin films.
9. The application according to claim 8, characterized in that: The photothermal material is loaded onto a substrate material.
10. The application according to claim 9, characterized in that: The substrate material includes a polypropylene fiber film.