Near-infrared photothermal molecule, preparation method thereof and application of near-infrared photothermal molecule in photoresponse polyimide material

Abstract

The invention discloses a near-infrared photothermal molecule, a preparation method thereof and an application of the near-infrared photothermal molecule in a photoresponse polyimide material. The structure of the near-infrared photothermal molecule is shown as the following formula. The photothermal molecules with donor-acceptor-donor configuration are designed and are suitable for preparing the photoresponse polyimide material, so that the agglomeration phenomenon caused by doping inorganic particles in the polymer can be avoided, and the original mechanical property of the polymer is well maintained; the high-efficiency non-radiative transition capability of photo-thermal molecules in the polymer is realized, the obtained photo-response polyimide material has extremely high response speed to infrared light and realizes reversible response, violent deformation is immediately generated when the material is irradiated by near-infrared light, and the material almost recovers to the original form after the near-infrared light is turned off.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light-driven materials, in particular to a near-infrared photothermal molecule, a preparation method thereof and application thereof in a light-responsive polyimide material. BACKGROUND

[0002] Stimuli-responsive materials can change their shape, color or motion state under external environmental stimuli such as humidity, light, heat, pH or magnetic field, and therefore have broad application prospects in the fields of sensors, artificial muscles and soft robots. Among various stimuli sources, light is an ideal choice for driving responsive materials because it is easy to control the wavelength, intensity and polarization direction, and can achieve non-contact energy transmission. Especially since the 21st century, with the rapid development of bionic technology and artificial intelligence, intelligent polymer materials with light-induced deformation ability have become an international research hotspot. Traditionally, by introducing azobenzene groups into the main chain or side chain of a polymer, the material can be macroscopically deformed by using the trans-cis isomerization induced by ultraviolet light. Such materials have been widely used in the construction of intelligent deformation systems. However, ultraviolet light driving has the disadvantages of low biological safety, poor tissue penetration and easy to cause material photoaging, and the driving rate is relatively slow, which limits its application in biomedical and deep driving.

[0003] In recent years, near-infrared light-driven materials have gradually become a research focus due to their good biocompatibility, deep tissue penetration ability and low risk of photo-damage. Near-infrared light is almost harmless to biological tissues and can be safely used in in vivo environments, such as targeted drug delivery and endoscopic robots. Its scattering and absorption in polymers and biological tissues are weak, and it can penetrate centimeter-level depth, which is much better than ultraviolet light that can only penetrate micrometer-level depth. In addition, the low energy of near-infrared light makes it less likely to cause material degradation, which helps to improve the service life and operational safety of the device.

[0004] Currently, the common method to achieve near-infrared light response is to introduce inorganic photothermal components (such as gold nanoparticles, carbon nanotubes or graphene) into the polymer to introduce photothermal function. However, such composite materials often face problems such as uneven dispersion of inorganic particles, easy agglomeration and poor interfacial compatibility, which leads to a decrease in mechanical properties and limited photothermal response efficiency, and easy fatigue damage in cyclic use.

[0005] Therefore, it is urgent to develop a new type of near-infrared photothermal material that can be used to prepare near-infrared light-responsive polyimide intelligent materials with fast response speed, good stability and suitability for deep driving, to meet the urgent needs of high-performance light drivers in the fields of soft robots and other frontier fields. SUMMARY

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the present application aims to provide a near-infrared light-heat molecule and a near-infrared light-responsive polyimide material with extremely fast response speed.

[0007] The present application is realized by the following technical solutions: The present application provides a near-infrared light-heat molecule, which has the following structure: ; R1, R2 are each independently selected from the following groups: C5-C 20 linear alkyl, C5-C 20 branched alkyl, C5-C 20 cyclic alkyl chain, alkyl chain in which carbon atoms are substituted with one or more of oxygen atoms, sulfur atoms, nitrogen atoms, alkenyl, alkynyl, aryl, carbonyl, hydroxyl, amino, carboxyl, cyano, nitro and ester group, one of alkyl chain in which hydrogen atoms are substituted with one or more of fluorine atoms, chlorine atoms, bromine atoms and iodine atoms; R3, R4, R5, R6 are each independently selected from hydrogen, deuterium, halogen, C1-C 30 alkyl, C1-C 30 alkoxy, C1-C 30 thioalkyl, aryl, heteroaryl or triphenylamine and its derivatives; wherein the alkyl, alkoxy, thioalkyl, aryl, heteroaryl and triphenylamine and its derivatives are optionally substituted with one or more substituents independently selected from deuterium, halogen, cyano, nitro, amino, hydroxyl, C1-C 20 alkyl, C1-C 20 haloalkyl, C1-C 20 alkoxy, C3-C 10 cycloalkyl, C6-C 18 aryl, 5-18 membered heteroaryl.

[0008] Preferably, the aryl is selected from any one of phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, perylenyl; the heteroaryl is selected from any one of thienyl, furanyl, pyrrolyl, pyridyl, pyrimidinyl, quinolinyl; the triphenylamine and its derivatives are substituted with any one or more of oxygen atoms, nitrogen atoms, sulfur atoms, deuterium, halogen, cyano, nitro, amino, hydroxyl, C1-C 20 alkyl, C1-C 20 haloalkyl, C1-C 20 alkoxy, C3-C 10 cycloalkyl, C6-C 18 aryl, 5-18 membered heteroaryl.

[0009] Further, the near-infrared light-heat molecule is selected from the following structure: 、 、 、 、 、 、 ; -C in the above structure 10 H 21 -C8H 17 -C6H 13 -C4H9、-C 14 H 29 all represent linear alkyl groups.

[0010] The present application also provides a preparation method of the above near-infrared photothermal molecule, comprising the following steps: dissolving the compound 、 , a deprotonating agent, a ligand, and a catalyst in an organic solvent, mixing and refluxing, and after the reaction is completed, post-treatment is performed to obtain the near-infrared photothermal molecule; R1, R2 are each independently selected from one of the following groups: a linear C5-C 20 alkyl chain, a branched C5-C 20 alkyl chain, a cyclic C5-C 20 alkyl chain, an alkyl chain in which carbon atoms are substituted with one or more of oxygen atoms, sulfur atoms, nitrogen atoms, alkenyl groups, alkynyl groups, aryl groups, carbonyl groups, hydroxyl groups, amino groups, carboxyl groups, cyano groups, nitro groups, and ester groups, and an alkyl chain in which hydrogen atoms are substituted with one or more of fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; R' is selected from one or more of the following groups: hydrogen, deuterium, halogen, C1-C 30 alkyl, C1-C 30 alkoxy, C1-C 30 thioalkyl, aryl, heteroaryl, triphenylamine, and derivatives thereof.

[0011] Preferably, the deprotonating agent is sodium tert-butoxide or potassium tert-butoxide.

[0012] Preferably, the ligand is tri-tert-butylphosphine tetrafluoroborate, 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl, or 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl.

[0013] Preferably, the catalyst is tris(dibenzylideneacetone)dipalladium(0) or palladium acetate.

[0014] The compound of the present application The organic solvent I and the organic solvent II can be commercially available or self-made, and can be prepared according to the method disclosed in Chinese Patent Application CN202510199792.8.

[0015] The present application also provides application of the near-infrared photothermal molecule in the light-responsive polyimide material.

[0016] The present application also provides a near-infrared light-responsive polyimide material comprising the near-infrared photothermal molecule.

[0017] The present application also provides a preparation method of the near-infrared light-responsive polyimide material, comprising the following steps: The imide ring-containing dimercapto monomer and the imide ring-containing dialkynyl monomer are dissolved in the organic solvent I, and the reaction is carried out at 20-80℃ for 10-360 min under a nitrogen atmosphere. After the reaction is completed, the reaction solution is introduced into methanol to precipitate the fibrous solid product. After filtration, washing and drying, the polyimide is obtained. The near-infrared photothermal molecule is dissolved in the organic solvent I, and the polyimide is dissolved in the organic solvent II. After mixing the two solutions, the mixture is filtered through a four-fluorine filter core and then cast or spin-coated on a substrate. The substrate is treated in a vacuum oven at 60-120℃ for 48-72 h to obtain a polyimide film doped with the photothermal molecule. The polyimide film is placed under an ultraviolet lamp with a power density of 5 mW / cm 2 ~ 5 W / cm 2 and a wavelength of 10-450 nm for irradiation for 1 min-24 h to obtain the near-infrared light-responsive polyimide material.

[0018] Preferably, the organic solvent I is at least one selected from tetrahydrofuran, dioxane, toluene, chloroform, acetone, ethylene glycol dimethyl ether, acetonitrile, nitrobenzene, dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, m-cresol, phenol, p-chlorophenol, o-dichlorobenzene, 1,2,4-trichlorobenzene, N-methylpyrrolidone, dimethyl sulfoxide, gamma-butyrolactone and ethyl acetate.

[0019] Preferably, the organic solvent II is at least one selected from tetrahydrofuran, dioxane, chloroform, dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, m-cresol, phenol, p-chlorophenol, o-dichlorobenzene, 1,2,4-trichlorobenzene, N-methylpyrrolidone, dimethyl sulfoxide, gamma-butyrolactone and ethyl acetate.

[0020] Preferably, the structure of the imide ring-containing dimercapto monomer is and the structure of the imide ring-containing dialkynyl monomer is ; wherein X represents an aromatic or aliphatic ring element.

[0021] Preferably, X represents any one of the following structural formulae: , , , , , , .

[0022] The imide ring-containing dimercapto monomer and the imide ring-containing dialkynyl monomer can be obtained commercially or by self-preparation, and can be prepared by referring to the method disclosed in Chinese Patent Application CN202410768982.2.

[0023] Preferably, the thickness of the near-infrared light responsive polyimide material of the present application is 3-500 μm.

[0024] The present application also provides the application of the near-infrared light responsive polyimide material in optical drives, sensors, artificial muscles or soft robots.

[0025] The present application has the following beneficial effects: The present application designs a photothermal molecule with a donor-acceptor-donor (D-A-D) configuration, which has the following advantages: 1. The photothermal molecule can effectively promote intramolecular charge transfer (ICT) and form a twisted intramolecular charge transfer (TICT) state, thereby significantly broadening and red-shifting the absorption and emission spectra of the molecule; 2. More importantly, the high-efficiency non-radiative transition ability is ensured, which lays a structural foundation for achieving excellent photothermal conversion performance; 3. The introduction of alkyl chain substitution in the molecular structure not only improves the solubility of the molecule in various solvents, but more importantly, when the molecule aggregates, the bulky steric hindrance effect can effectively reduce the close packing between molecules. This design ensures that even in the aggregated state, the molecule still has ample free space for active intramolecular motion (such as rotation and vibration), thereby effectively releasing the absorbed light energy in the form of heat energy; 4. The carbon-carbon double bond in the molecular structure provides efficient free motion activity structure for the two connected parts, ensuring that each part of the molecule can fully rotate / vibrate in the aggregated state, thereby having high-efficiency photothermal performance.

[0026] The photothermal molecule of the present application is suitable for preparing a light-responsive polyimide material, which can not only avoid the agglomeration phenomenon of inorganic particles doped in the polymer, well maintain the mechanical properties of the original polymer, but also realize the high-efficiency non-radiative transition ability of the photothermal molecule in the polymer. The obtained light-responsive polyimide material has extremely fast response speed to infrared light and realizes reversible response. When the near-infrared light is irradiated, the material can immediately produce a sharp deformation (the response bending deformation is ≥155° within 1s, and the deformation is enough to lift the heavy object placed above), and can almost restore to the original shape after the near-infrared light is turned off.

[0027] The present application realizes the preparation of high-performance near-infrared light-responsive polyimide material, which has great application prospect in the fields of soft robots and other frontiers. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The proton nuclear magnetic resonance spectrum characterization of the near-infrared photothermal molecule obtained in Example 1 is shown in Table 1. Figure 2 The mass spectrum characterization of the near-infrared photothermal molecule obtained in Example 1 is shown in Table 2. Figure 3 The emission spectrum of the near-infrared photothermal molecule obtained in Example 1 in different proportions of tetrahydrofuran and water mixed solvents, and the fluorescence intensity and wavelength change after adding the poor solvent water are shown in Table 3. Figure 4 The photo of the near-infrared light-responsive polyimide material is shown in Figure 1. Figure 5 The light response schematic diagram of the near-infrared light-responsive polyimide material in Application Example 1 is shown in Figure 2. Figure 6 The schematic diagram of the near-infrared light-responsive polyimide material lifting the heavy object in Application Example 1 is shown in Figure 3. DETAILED DESCRIPTION

[0029] The following examples are provided to better further understand the present application, and do not limit the content and protection scope of the present application. Any person who obtains any product same or similar to the present application under the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application.

[0030] The specific experimental steps or conditions not mentioned in the examples can be carried out according to the conventional experimental steps or conditions described in the literature in the art. The reagents or instruments not mentioned by the manufacturer are conventional reagent products that can be obtained by market purchase.

[0031] Unless otherwise specified, the room temperature or normal temperature in the examples of the present application refers to 25±3℃.

[0032] Compound i (1) wherein -C 10 H 21 , -C8H 17 all represent linear alkyl groups): prepared according to the method disclosed in Chinese patent application CN202510199792.8.

[0033] Compound ii (Formula II): wherein -C6H 13 all represent linear alkyl groups): prepared according to the method disclosed in Chinese patent application CN202510199792.8.

[0034] Compound iii (Formula III): ): prepared according to the method disclosed in Chinese patent application CN202510199792.8.

[0035] Compound iv (Formula IV): wherein -C 14 H 29 all represent linear alkyl groups): prepared according to the method disclosed in Chinese patent application CN202510199792.8.

[0036] Dithiol monomer i (Formula V): ): 4.4424 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride was added at one time into a three-necked flask equipped with a water separator and a condenser reflux device, 121 g of acetic acid was added under argon atmosphere and mechanical stirring was started, 2.5038 g of p-aminobenzenethiol and 25 mL of cyclohexane were added in sequence and the system was heated to reflux. After refluxing for 4 h, the reaction solution was slowly cooled to 25 °C, poured into distilled water, suction filtered, and the filter cake was washed with distilled water for 3 times. The filter cake was dried in a vacuum oven at 80 °C for 24 h to obtain dithiol monomer i (yield 94 %).

[0037] Dithiol monomer ii (Formula VI): ): 6.6845 g of N,N'-(2,2-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diyl)bis(1,3-dioxo-1,3- dihydroisobenzofuran-5-carboxamide) was added at one time into a three-necked flask equipped with a water separator and a condenser reflux device, 121 g of acetic acid was added under argon atmosphere and mechanical stirring was started, 2.5038 g of p-aminobenzenethiol and 25 mL of cyclohexane were added in sequence and the system was heated to reflux. After refluxing for 6 h, the reaction solution was slowly cooled to 25 °C, poured into distilled water, suction filtered, and the filter cake was washed with distilled water for 3 times. The filter cake was dried in a vacuum oven at 80 °C for 24 h to obtain dithiol monomer ii (yield 96 %).

[0038] Dialkynyl monomer i (Formula VII): ): 6.6845 g of N,N'-(2,2-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diyl)bis(1,3- dioxo-1,3-dihydroisobenzofuran-5-carboxamide) was added at one time to a three- necked flask equipped with a water separator and a reflux condenser, 121 g of acetic acid was added under argon atmosphere and mechanical stirring was started, 2.3430 g of m- aminophenylacetylene and 25 mL of cyclohexane were added in sequence and the system was heated to reflux. After 6 h of reflux, the reaction was slowly cooled to 25 °C, the reaction liquid was poured into distilled water, suction filtration was performed and the filter cake was washed three times with distilled water. The filter cake was dried in a vacuum oven at 80 °C for 24 h to obtain the diacetylenic monomer i (yield 91 %).

[0039] diacetylenic monomer ii ): 4.4424 g of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride was added at one time to a three-necked flask equipped with a water separator and a reflux condenser, 121 g of acetic acid was added under argon atmosphere and mechanical stirring was started, 2.3430 g of m- aminophenylacetylene and 25 mL of cyclohexane were added in sequence and the system was heated to reflux. After 6 h of reflux, the reaction was slowly cooled to 25 °C, the reaction liquid was poured into distilled water, suction filtration was performed and the filter cake was washed three times with distilled water. The filter cake was dried in a vacuum oven at 80 °C for 24 h to obtain the diacetylenic monomer ii (yield 90 %).

[0040] Example 1 A method for preparing a near-infrared photothermal molecule, comprising the following steps:

[0041] Compound i (100 mg, 0.08 mmol), 4-(4-bromostyryl)-N,N-di-p-tolyl aniline (182 mg, 0.40 mmol), sodium tert-butoxide (53.6 mg, 0.56 mmol), 2-dicyclohexylphospho-2,4,6-triisopropylbiphenyl (18.2 mg, 0.04 mmol), tris(dibenzylideneacetone)dipalladium(0) (9.2 mg, 0.01 mmol) were dissolved in toluene and refluxed at 120 °C for 12 h under nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature, extracted with dichloromethane, and washed with brine three times. Subsequently, the mixture was dried over anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the residue was purified by silica gel column chromatography using dichloromethane and petroleum ether (2:1) as the eluent to obtain the product near-infrared photothermal molecule A with a yield of 55%.

[0042] Figure 1 The proton nuclear magnetic resonance spectrum of the near-infrared two-zone photothermal molecule A obtained in Example 1 was characterized, which was consistent with the designed molecule, proving the successful preparation of the molecule.

[0043] Figure 2 Mass spectrometry characterization of near-infrared two-region photothermal molecule A obtained in Example 1.

[0044] Figure 3 The emission spectrum of near-infrared two-region photothermal molecule A obtained in Example 1 in tetrahydrofuran solvent and the change in fluorescence intensity and wavelength after adding poor solvent water can be seen. The emission wavelength of the molecule in tetrahydrofuran is 900-1400 nm.

[0045] Example 2

[0046] A method for preparing a near-infrared photothermal molecule, which is different from Example 1 only in that the deprotonating agent is potassium tert-butoxide (62.8 mg, 0.56 mmol), and the remaining steps are the same as in Example 1.

[0047] The product near-infrared photothermal molecule A was prepared, with a yield of 50%.

[0048] Example 3

[0049] A method for preparing a near-infrared photothermal molecule, which is different from Example 1 only in that the deprotonating agent is potassium tert-butoxide (62.8 mg, 0.56 mmol), and the remaining steps are the same as in Example 1.

[0050] The product near-infrared photothermal molecule A was prepared, with a yield of 46%.

[0051] Example 4

[0052] A method for preparing a near-infrared photothermal molecule, which is different from Example 1 only in that the deprotonating agent is potassium tert-butoxide (62.8 mg, 0.56 mmol), and the remaining steps are the same as in Example 1.

[0053] The product near-infrared photothermal molecule A was prepared, with a yield of 49%.

[0054] Example 5

[0055] The difference from Example 1 is that compound i is replaced with an equimolar mass of compound ii, and 4-(4-bromostyryl)-N,N-di-p-tolyl aniline is replaced with an equimolar mass of p-bromo-(E)-3-chloropropenylbenzene. The other process steps and parameters are the same as in Example 1, and the product near-infrared photothermal molecule B is prepared, with a yield of 45%.

[0056] Example 6

[0057] The difference from Example 1 is that compound i is replaced by an equimolar amount of compound iii, and 4-(4-bromostyryl)-N,N-di-p-tolyl aniline is replaced by an equimolar amount of 4-bromostilbene. Other process steps and parameters are the same as those in Example 1, and near-infrared photothermal molecule C is prepared with a yield of 52%.

[0058] Example 7

[0059] The difference from Example 1 is that compound i is replaced by an equimolar amount of compound iv, and 4-(4-bromostyryl)-N,N-di-p-tolyl aniline is replaced by an equimolar amount of (E)-p-bromostyryl substituted triphenylamine. Other process steps and parameters are the same as those in Example 1, and near-infrared photothermal molecule D is prepared with a yield of 58%.

[0060] Application Example 1 A preparation method of a near-infrared light responsive polyimide material, comprising the following steps: Into a reaction vessel equipped with mechanical stirring, 0.6586 g of dimercaptan monomer i, 0.6425 g of diacetylenic monomer i and 9 mL of tetrahydrofuran were sequentially added, and stirred at 25°C for 15 min under nitrogen atmosphere. After the reaction was completed, the reaction solution was poured into methanol to precipitate fibrous solid product, which was filtered and the filter cake was washed with methanol for 3 times. The filter cake was dried in a vacuum oven at 80°C for 20 h to obtain polyimide A.

[0061] 0.20 g of polyimide A was dissolved in 5 g of N,N-dimethylformamide, and 0.1 mg of photothermal molecule A was dissolved in 2 g of dichloromethane. The two solutions were mixed uniformly and filtered through a four-fluorine filter with a pore size of 220 nm, and then cast on a glass plate previously adjusted to be horizontal. The glass plate was treated in a vacuum oven at 60°C for 72 h, and then taken out after the temperature dropped to 25°C. The film was taken off after being soaked in deionized water for 2.5 h, and vacuum dried at 150°C for 24 h to obtain a photothermal molecule doped polyimide film.

[0062] The polyimide film was placed under a 100 mW / cm 2 365 nm ultraviolet lamp for 20 min to obtain a near-infrared light responsive polyimide material I.

[0063] Figure 5is a schematic diagram of the near-infrared light response of the polyimide material. The near-infrared light response polyimide material sample (specification: thickness 10 microns; length 2.5 centimeters, width 0.5 centimeters) of application example 1 is placed under 808 nm near-infrared light, and it can be seen that it deforms rapidly, bending about 180° in 1 second, and almost returns to the original shape after the near-infrared light is turned off, and this process is reversible, indicating that the polyimide material of the application can respond to near-infrared light to achieve reversible driving.

[0064] Figure 6 is a schematic diagram of the polyimide material lifting the weight. A weight about 20 times the weight of the material is placed above the sample, and under 808 nm near-infrared light, it can be seen that the sample deforms rapidly to lift the weight, indicating that the near-infrared light response polyimide material of the application has excellent mechanical properties.

[0065] Application Example 2 A method for preparing a near-infrared light response polyimide material, which is different from application example 1 only in that the reaction monomers of the polyimide use 0.6586 g of dimercapto monomer ii and 0.6425 g of dialkynyl monomer i, and the remaining steps are the same as in application example 1. Near-infrared light response polyimide material II is prepared.

[0066] The near-infrared light response polyimide material sample of application example 2 is placed under 808 nm near-infrared light, and it can be seen that it bends about 170° in 1 second, and almost returns to the original shape after the near-infrared light is turned off, and this process is reversible.

[0067] Application Example 3 A method for preparing a near-infrared light response polyimide material, which is different from application example 1 only in that the reaction monomers of the polyimide use 0.6586 g of dimercapto monomer i and 0.6425 g of dialkynyl monomer ii, and the remaining steps are the same as in application example 1. Near-infrared light response polyimide material III is prepared.

[0068] The near-infrared light response polyimide material sample of application example 3 is placed under 808 nm near-infrared light, and it can be seen that it bends about 175° in 1 second, and almost returns to the original shape after the near-infrared light is turned off, and this process is reversible.

[0069] Application Example 4 A method for preparing a near-infrared light response polyimide material, which is different from application example 1 only in that the reaction monomers of the polyimide use 0.6586 g of dimercapto monomer ii and 0.6425 g of dialkynyl monomer ii, and the remaining steps are the same as in application example 1. Near-infrared light response polyimide material IV is prepared.

[0070] The application example 4 near-infrared light response polyimide material sample was placed under the near-infrared light of 808 nm, and it was found that it was bent by about 180° in 1 second, and almost restored to the original state after the near-infrared light was turned off, and the process was reversible.

[0071] Application Example 5 A preparation method of a near-infrared light response polyimide material, which is only different from application example 1 in that the photothermal molecule A is replaced by the photothermal molecule B, and the remaining steps are the same as application example 1. The near-infrared light response polyimide material V is prepared.

[0072] The application example 5 near-infrared light response polyimide material sample was placed under the near-infrared light of 808 nm, and it was found that it was bent by about 160° in 1 second, and almost restored to the original state after the near-infrared light was turned off, and the process was reversible.

[0073] Application Example 6 A preparation method of a near-infrared light response polyimide material, which is only different from application example 1 in that the photothermal molecule A is replaced by the photothermal molecule C, and the remaining steps are the same as application example 1. The near-infrared light response polyimide material VI is prepared.

[0074] The application example 6 near-infrared light response polyimide material sample was placed under the near-infrared light of 808 nm, and it was found that it was bent by about 155° in 1 second, and almost restored to the original state after the near-infrared light was turned off, and the process was reversible.

[0075] Application Example 7 A preparation method of a near-infrared light response polyimide material, which is only different from application example 1 in that the photothermal molecule A is replaced by the photothermal molecule D, and the remaining steps are the same as application example 1. The near-infrared light response polyimide material VII is prepared.

[0076] The application example 7 near-infrared light response polyimide material sample was placed under the near-infrared light of 808 nm, and it was found that it was bent by about 180° in 1 second, and almost restored to the original state after the near-infrared light was turned off, and the process was reversible.

[0077] Comparative Application Example The NDI-1 molecule was prepared according to the method disclosed in Chinese patent application CN202510199792.8.

[0078]

[0079] A preparation method of a near-infrared light response polyimide material, which is only different from application example 1 in that the photothermal molecule A is replaced by the NDI-1 molecule, and the remaining steps are the same as application example 1. The near-infrared light response polyimide material VIII is prepared.

[0080] The comparative application example near-infrared light response polyimide material sample is placed under 808 nm near-infrared light, and it can be seen that it bends about 120° in 1 second, and almost restores to the original form after the near-infrared light is turned off, and the process is reversible.

[0081] As can be seen from the above, the photothermal molecule designed in the application is particularly suitable for preparing light response polyimide materials, which can not only avoid the agglomeration phenomenon of inorganic particles doped in the polymer and well maintain the original mechanical properties of the polymer, but also realize the high-efficiency non-radiative transition ability of the photothermal molecule in the polymer, and the obtained light response polyimide material has extremely fast infrared light response speed and realizes reversible response, and when it is irradiated by near-infrared light, it immediately produces a sharp deformation (bends and deforms by more than 155° in 1s, and the deformation is enough to lift the heavy object placed above), and it can almost restore to the original form after the near-infrared light is turned off.

[0082] The application realizes the preparation of high-performance near-infrared light response polyimide materials, and has great application prospect in the fields of soft robots and other frontiers.

[0083] The above is only the preferred specific embodiment of the application, but the protection scope of the application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the application, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A near-infrared photothermal molecule, characterized in that, The structure is shown in the following formula: ； R1 and R2 are each independently selected from the following groups: C5-C 20 Straight-chain alkyl, C5-C 20 Branched alkyl groups, C5-C 20 A cyclic alkyl chain in which carbon atoms are substituted by one or more of oxygen atoms, sulfur atoms, nitrogen atoms, alkenyl, alkynyl, aryl, carbonyl, hydroxyl, amino, carboxyl, cyano, nitro and ester groups, and a alkyl chain in which hydrogen atoms are substituted by one or more of fluorine atoms, chlorine atoms, bromine atoms and iodine atoms. R3, R4, R5, R6are each independently selected from hydrogen, deuterium, halogen, C1-C 30 alkyl, C1-C 30 alkoxy, C1-C 30 thioalkyl, aryl, heteroaryl or triphenylamine and derivatives thereof; wherein the alkyl, alkoxy, thioalkyl, aryl, heteroaryl and triphenylamine and derivatives thereof are optionally substituted with one or more substituents independently selected from deuterium, halogen, cyano, nitro, amino, hydroxyl, C1-C 20 alkyl, C1-C 20 haloalkyl, C1-C 20 alkoxy, C3-C 10 cycloalkyl, C6-C 18 aryl, 5-18 membered heteroaryl.

2. The near infrared photothermal molecule of claim 1, wherein, the aryl group is selected from any one of phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, perylenyl; the heteroaryl group is selected from any one of thienyl, furanyl, pyrrolyl, pyridyl, pyrimidyl, quinolyl; the triphenylamine and its derivatives are substituted with any one or several of oxygen atom, nitrogen atom, sulfur atom at carbon atom, and hydrogen atom is substituted with deuterium, halogen, cyano, nitro, amino, hydroxyl, C1-C 20 alkyl, C1-C 20 haloalkyl, C1-C 20 alkoxy, C3-C 10 cycloalkyl, C6-C 18 aryl, 5-18 membered heteroaryl.

3. The near infrared photothermal molecule of claim 1, wherein, is selected from the following structures: 、 、 、 、 、 、 。 4. The method of preparing a near-infrared photothermal molecule according to any one of claims 1 to 3, characterized in that, comprising the following steps: The compound , , a deprotonating agent, a ligand, and a catalyst are dissolved in an organic solvent, mixed, and subjected to a reflux reaction. After the reaction is completed, post-treatment is performed, and the near-infrared photothermal molecule is obtained. R1, R2are each independently selected from one of the following groups: C5-C 20 straight chain, C5-C 20 branched chain, C5-C 20 cyclic alkyl chain, alkyl chain substituted with one or several of oxygen atoms, sulfur atoms, nitrogen atoms, alkenyl groups, alkynyl groups, aryl groups, carbonyl groups, hydroxyl groups, amino groups, carboxyl groups, cyano groups, nitro groups and ester groups, alkyl chain substituted with one or several of fluorine atoms, chlorine atoms, bromine atoms and iodine atoms; said R' is selected from one or more of the following groups: hydrogen, deuterium, halogen, C1-C 30 alkyl, C1-C 30 alkoxy, C1-C 30 thioalkyl, aryl, heteroaryl, triphenylamine and derivatives thereof; The deprotonating agent is sodium tert-butoxide or potassium tert-butoxide; The ligand is tri-tert-butylphosphine tetrafluoroborate, 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl or 2-dicyclohexylphosphine-2',6'-diisopropoxy-1,1'-biphenyl; The catalyst is tris(dibenzylideneacetone)dipalladium(0) or palladium acetate.

5. The use of the near-infrared photothermal molecule according to any one of claims 1-3 in a photoresponsive polyimide material.

6. A near-infrared light responsive polyimide material, characterized by, The near-infrared photothermal molecule according to any one of claims 1-3.

7. The method for preparing the near-infrared light-responsive polyimide material according to claim 6, characterized in that, comprising the following steps: The imide ring-containing dimercapto monomer and the imide ring-containing dialkynyl monomer are dissolved in an organic solvent I, and reacted at 20-80 °C for 10-360 min under a nitrogen atmosphere. After the reaction is completed, the reaction solution is introduced into methanol to precipitate a fibrous solid product. The product is filtered, washed and dried to obtain a polyimide. The near-infrared photothermal molecule is dissolved in an organic solvent I, and the polyimide is dissolved in an organic solvent II. After the two solutions are mixed and filtered through a four-fluorine filter, they are cast or spin-coated on a substrate, and treated in a vacuum oven at 60-120 °C for 48-72 h to obtain a polyimide film doped with the photothermal molecule. The polyimide film was irradiated under an ultraviolet lamp with a wavelength of 10-450 nm at a power density of 5 mW / cm 2 5 W / cm 2 for 1 min-24 h to obtain a near-infrared light-responsive polyimide material.

8. The preparation method of the near-infrared photoresponsive polyimide material according to claim 7, characterized in that, The organic solvent I is selected from at least one of tetrahydrofuran, dioxane, toluene, chloroform, acetone, ethylene glycol dimethyl ether, acetonitrile, nitrobenzene, dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, m-cresol, phenol, p-chlorophenol, o-dichlorobenzene, 1,2,4-trichlorobenzene, N-methylpyrrolidone, dimethyl sulfoxide, gamma-butyrolactone and ethyl acetate; The organic solvent II is selected from at least one of tetrahydrofuran, dioxane, chloroform, dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, m-cresol, phenol, p-chlorophenol, o-dichlorobenzene, 1,2,4-trichlorobenzene, N-methylpyrrolidone, dimethyl sulfoxide, gamma-butyrolactone and ethyl acetate; The structure of the imide ring-containing dimercapto monomer is ; The structure of the diacetylenic monomer containing an imide ring is ; wherein X represents an aromatic or aliphatic ring element.

9. The method for preparing the near-infrared light-responsive polyimide material according to claim 8, characterized in that, The X represents any one of the following structural formulas: 、 、 、 、 、 、 。 10. The use of the near-infrared photoresponsive polyimide material according to claim 6 in a photo driver, a sensor, an artificial muscle or a soft robot.

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