Temperature-ultraviolet light dual response functional polymer and preparation method thereof

Abstract

The application discloses a preparation method of a temperature-ultraviolet light double response type functional polymer, specifically comprising the following steps: preparing a macromolecular initiator PEG2-ABCPA; preparing a p-styrylmethyl diethanolamine borate monomer VMAB; and performing a free radical polymerization reaction on the macromolecular initiator PEG2-ABCPA, the p-styrylmethyl diethanolamine borate monomer VMAB and 7-(4-vinylbenzyloxy)-4-methyl coumarin VBC to obtain a block copolymer, i.e. the temperature-ultraviolet light double response type functional polymer. The polymer not only has unique amphiphilic properties, but also exhibits double response to temperature and ultraviolet light, thereby showing wide application prospects in the fields of drug controlled release, intelligent materials, photoelectric devices and the like.

Description

Technical Field

[0001] This invention belongs to the field of polymer preparation technology, specifically relating to a method for preparing a temperature-UV irradiation dual-responsive functional polymer, and also relating to the temperature-UV irradiation dual-responsive functional polymer. Background Technology

[0002] Amphiphilic block copolymers are widely used in cutting-edge fields such as drug delivery, tissue engineering, and nanotechnology due to their unique physicochemical properties, such as self-assembly ability, surface activity, and biocompatibility. These polymers are typically composed of hydrophilic and hydrophobic segments and can self-assemble in solution to form stable micelle structures, providing an important material basis for various biomedical applications.

[0003] Polyethylene glycol (PEG), a commonly used hydrophilic polymer, is an ideal hydrophilic segment for constructing amphiphilic block copolymers due to its excellent water solubility, biocompatibility, and chemical stability. However, single PEG segments are often insufficient to meet complex application requirements. Therefore, introducing other functional monomers through chemical modification to construct amphiphilic block copolymers with specific structures and functions has become a current research hotspot and challenge.

[0004] Current research techniques for the synthesis and application of amphiphilic block copolymers have several shortcomings. First, amphiphilic block copolymers prepared by traditional methods often have limited functionality, failing to meet the complex and diverse application requirements. Especially in cutting-edge fields such as drug delivery, tissue engineering, and nanotechnology, higher demands are placed on the structure and properties of materials, and traditional materials often cannot simultaneously meet multiple performance requirements such as hydrophilicity, hydrophobicity, biocompatibility, and responsiveness. Second, the preparation of amphiphilic block copolymers often involves cumbersome synthesis steps, low yields, and difficult purification. This not only increases production costs but also limits the widespread application of the materials. For example, some traditional synthesis methods require the use of toxic and harmful solvents or catalysts, causing environmental pollution and potentially negatively impacting the biocompatibility of the materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a temperature-UV light dual-responsive functional polymer, which not only has unique amphiphilic properties, but also exhibits dual responsiveness to temperature and UV light.

[0006] Another object of the present invention is to provide a temperature-UV light dual-responsive functional polymer.

[0007] The technical solution adopted in this invention is a method for preparing temperature-UV irradiation dual-responsive functional polymers, specifically implemented according to the following steps:

[0008] Step 1, preparation of the macromolecular initiator PEG2-ABCPA; specifically:

[0009] Step 2: Prepare p-styrene-methyldiethanolamine borate monomer VMAB;

[0010] Step 3 involves free radical polymerization of the macromolecular initiator PEG2-ABCPA, the styryl methyl diethanolamine borate monomer VMAB, and 7-(4-vinylbenzyloxy)-4-methylcoumarin VBC to obtain a block copolymer, which is a temperature-UV irradiation dual-responsive functional polymer.

[0011] The invention is further characterized in that,

[0012] Step 1 specifically involves:

[0013] Polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanopentanoic acid), 4-dimethylaminopyridine and dicyclohexylcarbodiimide were mixed, and dichloromethane and N,N-dimethylformamide dried with KO H were added. The mixture was stirred until completely dissolved, and the reaction was continued at room temperature for 20-24 hours. The mixture was then filtered under reduced pressure, and the filtrate was collected, evaporated by rotary evaporation, and then precipitated with diethyl ether 2-3 times. The precipitate was filtered again, and the precipitate was allowed to stand for 12-24 hours until the organic solvent had completely evaporated. After that, the precipitate was dried under vacuum to obtain the macromolecular initiator PEG2-ABCPA.

[0014] The molar ratio of polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanopentanoic acid), 4-dimethylaminopyridine and dicyclohexylcarbodiimide is 1.5-2.5:0.5-1.5:2.5-3.5:2.5-3.5.

[0015] Step 2 specifically involves:

[0016] N-methyldiethanolamine, boric acid, and toluene were mixed and subjected to a reflux reaction for 10-18 hours at 130-140°C. After the reaction was completed, the mixture was cooled to room temperature, and the remaining toluene was removed by vacuum pumping with water and oil pumps to obtain a solid product. The solid product was dissolved in acetone, and then p-chloromethylenestyrene was added dropwise. The mixture was slowly heated to 45-55°C and subjected to a reflux reaction for 2-3 hours. After the reaction was stopped, the mixture was cooled to room temperature, and sodium carbonate was slowly added to the mixture. The mixture was reacted for 2-3 hours. After the reaction was stopped, the mixture was filtered, rotary evaporated, and then dissolved in a mixed solvent of methanol and dichloromethane. The insoluble matter was filtered off, and the product was precipitated with petroleum ether. After the petroleum ether had completely evaporated, the mixture was dried under vacuum to obtain a yellow powdery solid, which is the p-styrene-methyldiethanolamine borate monomer.

[0017] The molar ratio of N-methyldiethanolamine, boric acid, p-chloromethylenestyrene, and sodium carbonate is 1.5-2.5:2-3:2.5-3.5:2.5-3.5.

[0018] Step 3 specifically involves:

[0019] PEG2-ABCPA, VMAB, and VBC were dissolved in a mixed solvent consisting of water and N,N-dimethylformamide. The solution was then transferred to a reactor, which underwent a cooling-vacuuming process three times to remove air. After stirring at room temperature for 30-40 minutes, the reactor was placed in an oil bath at 75-85°C for 30-40 hours. After the reaction, the mixture was cooled to room temperature, filtered, and the filtrate was precipitated with diethyl ether. The precipitate was then dissolved in a mixed solvent of water and DMF, placed in a dialysis bag, and dialyzed for three days with deionized water changed every 3 hours. Finally, the mixture was freeze-dried under vacuum to obtain the target polymer PEO. 45 -bP(VBC2-co-VMAB9) is a temperature- and UV-responsive functional polymer.

[0020] The molar ratio of PEG2-ABCPA, VMAB, and VBC is 3-5:95-105:5-7.

[0021] Another technical solution adopted in this invention is a functional polymer prepared by a method for preparing temperature-ultraviolet light dual-responsive functional polymers.

[0022] The beneficial effects of this invention are as follows: The method of this invention first synthesizes a macromolecular initiator PEG2-ABCPA through a specific chemical reaction. This initiator not only contains PEG segments but also introduces ABCPA (4,4-azobis(4-cyanopentanoic acid)) as an active center, providing a possibility for subsequent free radical polymerization reactions. Subsequently, using PEG2-ABCPA as a macromolecular initiator, through a free radical polymerization reaction, the monomers 7-(4-vinylbenzyloxy)-4-methylcoumarin (VBC) and p-styrene-methyldiethanolamine borate (VMAB) are incorporated into the PEG segments to form PEO. 45 -bP(VBC2-co-VMAB9) block copolymer. This polymer not only possesses unique amphiphilic properties but also exhibits dual responsiveness to temperature and ultraviolet light, thus showing broad application prospects in fields such as drug controlled release, smart materials, and optoelectronic devices. Attached Figure Description

[0023] Figure 1 This is a diagram illustrating the preparation process of the macromolecular initiator PEG2-ABCPA;

[0024] Figure 2This is a diagram illustrating the preparation process of N-methyldiethanolamine borate ester;

[0025] Figure 3 This is a diagram illustrating the preparation process of styrene-N-methyldiethanolamine borate.

[0026] Figure 4 It is a polymer PEO 45 Schematic diagram of the preparation process of -bP(VBC2-co-VMAB9);

[0027] Figure 5 It is a styrene-N-methyldiethanolamine borate. 1 H NMR spectrum;

[0028] Figure 6 It is a polymer PEO 45 -bP(VBC2-co-VMAB9) 1 H NMR spectrum;

[0029] Figure 7a These are polymers PEO at different concentrations. 45 Fluorescence emission spectrum of -bP(VBC2-co-VMAB9) in pyrene saturated aqueous solution;

[0030] Figure 7b This is a graph showing the change of I1 / I3 value with the concentration of the polymer solution;

[0031] Figure 8a This is the UV-Vis absorption spectrum of polymer micelles under 365nm UV light irradiation;

[0032] Figure 8b This is the UV-Vis absorption spectrum of polymer micelles under 254nm UV light irradiation;

[0033] Figure 8c It is the continuation of the illumination time I 320 Normalized change curve of values;

[0034] Figure 9a This is the fluorescence emission spectrum of polymer micelles under 365nm ultraviolet light irradiation;

[0035] Figure 9b This is the fluorescence emission spectrum of polymer micelles under 254nm ultraviolet light irradiation;

[0036] Figure 9c It is the continuation of the illumination time I 382 Normalized change curve of values;

[0037] Figure 10a This is the fluorescence emission spectrum of polymer micelles during the heating and cooling process before illumination;

[0038] Figure 10b During the heating and cooling process, I 382 Normalized change curve of values;

[0039] Figure 11a This is the fluorescence emission spectrum of polymer micelles during the heating and cooling process after 1.67 min of 365nm ultraviolet light irradiation;

[0040] Figure 11b After 1.67 minutes of irradiation with 365nm ultraviolet light, during the temperature rise and fall process, I... 382 Normalized change curve of values;

[0041] Figure 12a This is the fluorescence emission spectrum of polymer micelles during the heating and cooling process after irradiation with 365nm ultraviolet light for 8.33 minutes.

[0042] Figure 12b After 8.33 minutes of irradiation with 365nm ultraviolet light, during the temperature rise and fall process, I... 382 Normalized change curve of values;

[0043] Figure 13a This is the fluorescence emission spectrum of polymer micelles during the heating and cooling process after 20 minutes of 365nm ultraviolet light irradiation;

[0044] Figure 13b It is the temperature rise and fall process after 20 minutes of 365nm ultraviolet light irradiation. 382 Normalized variation curve of values

[0045] Figure 14a The fluorescence emission spectrum of polymer micelles during the heating and cooling process is as follows: after irradiation with 365nm ultraviolet light for 20 minutes, irradiation was continued with 254nm ultraviolet light for another 20 minutes.

[0046] Figure 14b After irradiation with 365nm ultraviolet light for 20 minutes, irradiation was continued with 254nm ultraviolet light for another 20 minutes. During the temperature rise and fall process, I... 382 Normalized change curve of values;

[0047] Figure 15 This diagram illustrates the phase transitions of borate quaternary ammonium salt ions during heating, both intermolecular and intramolecular, as well as the phase transitions of PVMAB chain segments during heating and cooling. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0049] The preparation method of the temperature-UV light dual-responsive functional polymer of the present invention is carried out according to the following steps:

[0050] Step 1, preparation of the macromolecular initiator PEG2-ABCPA; specifically:

[0051] Polyethylene glycol monomethyl ether (PEG), 4,4-azobis(4-cyanopentanoic acid) (ABCPA), 4-dimethylaminopyridine (DMAP), and dicyclohexylcarbodiimide (DCC) were mixed, and dichloromethane and N,N-dimethylformamide dried with KOH were added. The mixture was magnetically stirred until completely dissolved, and the reaction was continued at room temperature for 20-24 hours. The reaction solution was filtered under reduced pressure using a Buchner funnel, and the filtrate was collected. The precipitate was discarded (to remove unreacted monomers, initiators, catalysts, and other impurities). The filtrate was then rotary evaporated at 30°C to remove impurities and solvents. The filtrate was then precipitated 2-3 times with diethyl ether (ether to filtrate volume ratio 20:1), filtered again, and allowed to stand for 12-24 hours. After the organic solvent had completely evaporated, the precipitate was vacuum dried for 12 hours to obtain the macromolecular initiator PEG2-ABCPA.

[0052] The molar ratio of polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanopentanoic acid), 4-dimethylaminopyridine and dicyclohexylcarbodiimide is 1.5-2.5:0.5-1.5:2.5-3.5:2.5-3.5;

[0053] Step 2, preparation of p-styrene-methyldiethanolamine borate monomer (VMAB); specifically:

[0054] N-methyldiethanolamine, boric acid, and toluene were mixed and subjected to reflux reaction for 10-18 hours at a temperature of 130-140°C. Water carried out by the toluene during the reaction was continuously released. After the reaction was completed, the mixture was cooled to room temperature. The remaining toluene in the flask was removed by vacuum pumping with water and oil pumps in sequence to obtain a pale yellow solid product.

[0055] The obtained solid product was dissolved in acetone, and then p-chloromethylstyrene was added dropwise. The temperature was slowly raised to 45-55℃ and refluxed for 2-3 hours. After the reaction stopped, the mixture was cooled to room temperature, and sodium carbonate was slowly added to the mixture. The reaction was carried out for 2-3 hours to remove chloride ions from p-chloromethylstyrene and form a quaternary ammonium borate ester. After the reaction stopped, sodium carbonate was removed by suction filtration, and acetone solvent was removed by rotary evaporation. The product was then dissolved in a mixed solvent of methanol and dichloromethane (volume ratio 1:1). The insoluble matter was filtered out, and the product was precipitated three times with petroleum ether. After the petroleum ether had completely evaporated, the product was dried under vacuum to obtain a yellow powdery solid, which is p-styrene-methyldiethanolamine borate ester monomer (VMAB).

[0056] The molar ratio of N-methyldiethanolamine, boric acid, p-chloromethylenestyrene, and sodium carbonate is 1.5-2.5:2-3:2.5-3.5:2.5-3.5;

[0057] Step 3: Free radical polymerization was carried out using the macromolecular initiator PEG2-ABCPA, p-styrene-methyldiethanolamine borate monomer, and 7-(4-vinylbenzyloxy)-4-methylcoumarin VBC to obtain the block copolymer PEO. 45 -bP(VBC2-co-VMAB9); specifically:

[0058] Using PEG2-ABCPA as a macromolecular initiator, VMAB as a hydrophilic monomer, and VBC as a hydrophobic monomer, PEG2-ABCPA, VMAB, and VBC were dissolved in a mixed solvent (a mixture of water and N,N-dimethylformamide in a volume ratio of 3:5). The solution was then transferred to a reactor, which underwent three cooling-vacuuming operations to remove air. After stirring at room temperature for 30-40 minutes, the reactor was placed in an oil bath at 75-85°C for stirring and reaction for 30-40 hours. After the reaction, the solution was cooled to room temperature, and the yellow viscous precipitate was removed by filtration, yielding an orange-red filtrate. This filtrate was precipitated three times with diethyl ether. The precipitate was then dissolved in a small amount of a mixed solvent of water and DMF, placed in a dialysis bag (Mw = 3500 g / mol), and dialyzed for three days with deionized water replaced every 3 hours. Finally, the resulting material was freeze-dried under vacuum to obtain the target polymer PEO. 45 -bP(VBC2-co-VMAB9) is a temperature- and UV-responsive functional polymer.

[0059] The molar ratio of PEG2-ABCPA, VMAB, and VBC is 3-5:95-105:5-7;

[0060] This invention successfully synthesizes a novel polymer with temperature and UV light sensitivity by combining monomers such as polyethylene glycol (PEG), p-styrene-methyldiethanolamine borate (VMAB), and 7-(4-vinylbenzyloxy)-4-methylcoumarin (VBC). This polymer not only has a simple synthesis procedure but also boasts high yield and easy purification, making large-scale production and widespread application possible.

[0061] Furthermore, this invention also explores PEO 45 The self-assembly behavior of -bP(VBC2-co-VMAB9) block copolymers in aqueous solution was investigated, and homogeneous polymer micelle aqueous solutions were prepared by direct dissolution. The chemical environment of coumarin in the polymer micelle solution was studied using a fluorescence spectrophotometer. It was found that the polymer can spontaneously form stable micelle structures in aqueous solution, and the coumarin groups exhibit specific fluorescent properties within the micelles. This provides important theoretical basis and experimental support for the application of polymer micelles.

[0062] Example 1

[0063] The preparation method of the temperature-UV light dual-responsive functional polymer of the present invention is carried out according to the following steps:

[0064] Step 1, preparation of the macromolecular initiator PEG2-ABCPA; specifically:

[0065] like Figure 1 As shown, 0.04 mmol of polyethylene glycol monomethyl ether (PEG), 4,4-azobis(4-cyanopentanoic acid) (ABCPA), 0.02 mmol of 4-dimethylaminopyridine (DMAP) and 0.006 mmol of dicyclohexylcarbodiimide (DCC) were mixed, and 90 mL of dichloromethane and N,N-dimethylformamide dried with KOH were added. The mixture was magnetically stirred until completely dissolved, and the reaction was continued to be stirred at room temperature for 24 h. The reaction solution was filtered under reduced pressure using a Buchner funnel, and the filtrate was collected. The precipitate was discarded (to remove unreacted monomers, initiators, catalysts, and other impurities). The filtrate was then rotary evaporated at 30 °C using a rotary evaporator to remove impurities and solvents. The filtrate was then precipitated twice with diethyl ether (the volume ratio of diethyl ether to filtrate was 20:1), filtered again, and allowed to stand for 12 h. After the organic solvent had completely evaporated, the precipitate was vacuum dried for 12 h to obtain the macromolecular initiator PEG2-ABCPA.

[0066] A macromolecular initiator, PEG2-ABCPA, was successfully synthesized through a specific chemical reaction. This initiator played a crucial role in the subsequent polymerization reaction, providing a foundation for the synthesis of block copolymers. After steps including rotary evaporation to remove impurities and solvents, ether precipitation, and vacuum drying, the final yield of the macromolecular initiator was 85.87%, with high purity, providing high-quality raw materials for subsequent reactions.

[0067] Step 2, preparation of p-styrene-methyldiethanolamine borate monomer (VMAB); specifically:

[0068] like Figure 2 As shown, 0.75 mol N-methyldiethanolamine, 0.97 mol boric acid, and 200 mL toluene were mixed and subjected to reflux reaction for 12 h at a reflux temperature of 140 °C. Water carried out by the toluene during the reaction was continuously released. After the reaction was completed, the mixture was cooled to room temperature, and the remaining toluene in the flask was removed by vacuum pumping with a water pump and an oil pump in sequence to obtain a pale yellow solid product.

[0069] The obtained solid product was dissolved in 200 mL of acetone, and then 1.125 mol of p-chloromethylstyrene was added dropwise. The temperature was slowly raised to 50 °C, and the mixture was refluxed for 2 hours. After the reaction stopped, the mixture was cooled to room temperature, and 1.125 mol of sodium carbonate was slowly added to the flask after the reaction. The mixture was reacted for 2 hours to remove chloride ions from p-chloromethylstyrene, forming a quaternary ammonium borate ester. After the reaction stopped, the sodium carbonate was removed by suction filtration, and the acetone solvent was removed by rotary evaporation. The product was then dissolved in a mixed solvent of methanol and dichloromethane (volume ratio 1:1), and the insoluble matter was filtered off. The product was precipitated three times with petroleum ether. After the petroleum ether had completely evaporated, the product was dried under vacuum to obtain a yellow powdery solid, which is p-styrene-methyldiethanolamine borate monomer (VMAB). Figure 3 As shown;

[0070] A two-step chemical reaction successfully synthesized the p-styrene-methyldiethanolamine borate monomer (VMAB). This monomer possesses unique chemical structure and properties, and is a component of the final block copolymer PEO. 45 -bP(VMAB9-co-VBC2) is an important component. After dissolving in a mixed solvent of methanol and dichloromethane, filtering, precipitating with petroleum ether, and vacuum drying, the final yield of VMAB was 80%, with high purity, providing a reliable raw material for subsequent reactions. 1 H NMR(400MHz,D2O)δ(ppm):7.4&7.3(d,4H,Ar-H),6.7(t,1H,ArCH=),5.8(dd,1H,CH2=),5.3(d,1H ,CH2=),4.5(s,2H,ArCH2-),4.0-3.9(t,4H,-CH2O-),3.5-3.3(tt,4H,-NCH2-),2.9(s,3H,CH3-);

[0071] Step 3, Preparation of polymer PEO 45 -bP(VBC2-co-VMAB9), specifically:

[0072] like Figure 4As shown, 0.51 mmol PEG2-ABCPA, 12.69 mmol VMAB, and 0.76 mmol VBC were dissolved in a mixed solvent (the mixed solvent was a mixture of water and N,N-dimethylformamide in a volume ratio of 3:5). The solution was then transferred to a reactor, and the reactor was subjected to a cooling-vacuuming operation three times to remove all air. After stirring at room temperature for 30 minutes, the reactor was placed in an oil bath at 78°C for stirring and reaction for 36 hours. After the reaction, the solution was cooled to room temperature, and the yellow viscous precipitate was removed by filtration, yielding an orange-red filtrate. This filtrate was precipitated three times with diethyl ether as the precipitant. The precipitate was then dissolved in a small amount of a mixed solvent of water and DMF, placed in a dialysis bag (Mw = 3500 g / mol), and the deionized water was changed every 3 hours for three days. Finally, the obtained substance was freeze-dried under vacuum to obtain the block copolymer PEO. 45 -bP(VBC2-co-VMAB9) is a temperature-UV light dual-responsive functional polymer with a yield of 76%. 1 H NMR(400MHz,D2O)δ(ppm):8.0-5.7(m,Ar-H),5.1(s,-CH2O-for VBC),4.5(s,ArCH2-for VMAB),4.2-3.8(s,-CH2O-B<),3.8-3.1(m,-CH2OC H2-forPEG&-NCH2-),2.9(s,>N-CH3),2.5-0.5(m,-CH3&-CH3);

[0073] Because polymer segments have varying water solubility, micelles are mainly prepared using two methods: dialysis and direct dissolution. PEO 45 -bP(VBC2-co-VMAB9) has a relatively long hydrophilic chain segment and good water solubility, allowing it to be directly dissolved in water to prepare micelles. Weigh 80 mg of polymer PEO... 45 -bP(VBC2-co-VMAB9) was directly dissolved in ultrapure water and stirred at a constant speed for 12 h to prepare a homogeneous polymer micelle aqueous solution with a micelle concentration of 10 mg / mL. The micelle behavior of the polymer was studied using a fluorescence spectrophotometer.

[0074] Using PEG2-ABCPA as a macromolecular initiator, VMAB as a hydrophilic monomer, and VBC as a hydrophobic monomer, a block copolymer PEO was successfully synthesized via free radical polymerization. 45-bP(VBC2-co-VMAB9). This copolymer possesses unique amphiphilic properties and temperature and UV responsiveness, showing broad application prospects in drug delivery, tissue engineering, and other fields. After steps including ether precipitation, dialysis, and vacuum freeze-drying, the final polymer yield was 44.35%, with high purity, providing a high-quality material basis for subsequent application research.

[0075] Example 2

[0076] 1 H NMR spectral analysis

[0077] To confirm that the synthesized polymer is the target product PEO 45 -bP(VBC2-co-VMAB9), this invention describes the synthesized substance and intermediate product (monomer VMAB) and its processing. 1 The results of the 1H NMR spectrum analysis are as follows:

[0078] Figure 5 For the single VMAB 1 ¹H NMR spectra (solvent: D₂O). Hydrogens at 7.4, 7.3, 6.7, 5.8, and 5.3 ppm are attributed to hydrogens on the benzene ring, with an integration ratio of 2 / 2 / 1 / 1 / 1. The hydrogen at 4.5 ppm is attributed to -CH₂ atoms attached to the benzene ring. Hydrogen proton signals at 4.0–3.9 and 3.5–3.3 ppm correspond to hydrogens on -CH₂ atoms within the eight-membered borate ester. The hydrogen proton signal observed at 2.9 ppm corresponds to hydrogens on -CH₃ atoms within the quaternary ammonium salt. Figure 6 For the target polymer 1 The 1H NMR spectrum shows a proton peak for the benzene ring in the 5.7-8.0 ppm range. The singlet at 4.5 ppm is attributed to the -CH2- proton characteristic peak of the p-styrene-methyldiethanolamine borate structure linked to the benzene ring. The multiple absorption peaks in the 3.8-4.2 ppm range represent the proton peaks of the -CH2OCH2- group in the PEO macroinitiator segment and the hydrogen on the -NCH2- group in the quaternary ammonium salt. Based on the integrated peak area ratios of these three characteristic peaks, the polymer is calculated to contain 2 VBC monomer units and 9 VMAB monomer units. The target polymer can be labeled as PEO. 45 -bP(VBC2-co-VMAB9).

[0079] Example 3

[0080] Performance characterization of polymer micelles

[0081] Before conducting a systematic study on the micelles formed by the target polymer, the CMC value of the polymer was first determined using the pyrene probe technique. For example... Figure 7aThe image shows the fluorescence emission spectra of pyrene saturated aqueous solutions containing different polymer concentrations. It can be clearly seen that the characteristic five-finger absorption band of pyrene is present in the wavelength range of 350-550 nm, and its intensity changes continuously with the change of polymer solution concentration. Figure 7b The correlation curves of the fluorescence intensity ratio at 373 nm (I1) and 384 nm (I3) in the five-finger absorption band as a function of polymer solution concentration were summarized. When the polymer concentration is below 1.67 × 10⁻⁶, the correlation curves were summarized. -3 At a concentration of mg / mL, the I1 / I3 ratio remained almost unchanged; however, as the polymer concentration gradually increased to 1.67 × 10 mg / mL, the I1 / I3 ratio remained almost unchanged. -3 At a concentration of mg / mL, the I1 / I3 value undergoes a sudden change and rapidly decreases. This change indicates that polymer molecules begin to form micelle aggregates from a dispersed free state, and pyrene molecules gradually enter the hydrophobic core of the polymer micelles from the aqueous solution. This allows for the determination of the polymer PEO... 45 The CMC value of -bP(VBC2-co-VMAB9) in aqueous solution is 1.67 × 10⁻⁶. -3 mg / mL.

[0082] Example 4

[0083] Photoresponsive behavior of polymer micelles under combined illumination

[0084] First, the UV-Vis absorption spectra of the obtained polymer micelles (PM) were characterized and analyzed. For example... Figure 8a As shown, PM exhibits a characteristic absorption peak resembling a shoulder in the wavelength range of 280-380 nm. With the increase at 365 nm (80 mW / cm²), the absorption peak decreases further. 2 With the cumulative duration of ultraviolet light exposure, the intensity of this characteristic absorption peak decreases significantly. This is due to the [2+2] cycloaddition reaction of the coumarin moiety. Figure 8b After irradiating the polymer micelles with 365nm ultraviolet light for 20 minutes, the light was switched to 254nm (8mW / cm²). 2 The UV-Vis absorption spectrum changes after continued UV irradiation of the micelles show a slow increase in the shoulder peak within the 280-380 nm wavelength range. This is because the dissociation behavior of the coumarin dimer under 254 nm UV irradiation exhibits a significant photoresponse correlation with its UV-Vis absorption spectrum changes. This phenomenon originates from the reverse [2+2] cycloaddition dissociation mechanism of the coumarin dimer. Simultaneously, the molar absorptivity of the free aromatic ring in the monomer structure significantly increases, directly manifested as an increase in the intensity of the characteristic absorption peak in the 300-350 nm range. This photocontrolled reversible behavior reveals the molecular mechanism of wavelength-selective regulation of the dimer-monomer dynamic equilibrium, providing a crucial basis for optimizing the dynamic performance of photoresponsive materials.

[0085] To more clearly observe and compare the degree of change of this characteristic absorption peak during irradiation with a combination of 365 / 254nm ultraviolet light. Figure 8c The ultraviolet absorbance values ​​at a wavelength of 320 nm were summarized (I 320 The normalized variation curve of ) is shown. It can be seen that irradiation of polymer micelles with a single 365nm ultraviolet light induces I more effectively than irradiation with a single 254nm ultraviolet light. 320 The value exhibits a more dramatic exponential variation, a phenomenon stemming from the differences in the photochemical reaction kinetics of coumarin motifs induced by 365nm and 254nm ultraviolet light, as well as the photon energy matching characteristics.

[0086] The reversible photodimerization process of coumarin moieties in PM was explained by analyzing the changes in fluorescence emission spectra during illumination. For example... Figure 9a As shown, at an excitation wavelength of 320 nm, the maximum fluorescence emission intensity of the polymer micelle aqueous solution appears at 382 nm (I 382 At this location; the micelles were cumulatively irradiated with 365nm ultraviolet light for 1.67 minutes, and the intensity of this characteristic peak continuously increased; the light stimulation was continued (cumulative irradiation time up to 20 minutes), I 382 The fluorescence intensity decreased to some extent. This is because the coumarin units in the hydrophobic segments of the polymer underwent photodimerization within 0-1.67 min of illumination, leading to cross-linking and entanglement between polymer chains, increased cross-linking density of the micelle core, more compact and aggregated micelle morphology, and increased fluorescence intensity. However, during this photocross-linking process, more and more coumarin units formed coumarin dimers, which caused the PEO polymer to... 45 The proportion of VBC components, which are relatively small in content in -bP(VBC2-co-VMAB9), decreases significantly in the entire polymer micelles. Therefore, when the micelles are irradiated with 365nm ultraviolet light, the fluorescence intensity shows a certain downward trend.

[0087] Subsequently, the polymer micelles were irradiated with 254nm ultraviolet light. Figure 9b The intensity of this fluorescence emission characteristic peak again showed a trend of first increasing and then decreasing, and this "increase-decrease" amplitude was significantly weaker than the photoresponse change induced by 365nm ultraviolet light. The main reason for this change is that a small portion of the coumarin dimer can undergo photodissociation under 254nm light irradiation, leading to I... 382 A slight increase; however, under prolonged exposure to 254nm ultraviolet light, the dissociated coumarin units underwent another irreversible photodimerization reaction, causing I... 382 The value decreased.

[0088] The above research results indicate that by adjusting the duration of combined ultraviolet light irradiation, the photoresponse performance of the hydrophobic segment components of polymers can be instantly controlled.

[0089] Example 5

[0090] Thermosensitive behavior of polymer micelles under temperature change

[0091] For polymer PEO 45 Fluorescence emission spectroscopy tracking tests were performed on βP(VBC2-co-VMAB9) micelle aqueous solutions under single 365nm and combined UV irradiation for different durations. The fluorescence intensity (Ig) at 382nm in the spectra was also analyzed. 382 The analysis and discussion were also conducted. Figure 10a This is the fluorescence emission spectrum of polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process before illumination; Figure 10b During the heating and cooling process, I 382 Normalized change curve of values;

[0092] Figure 11a The fluorescence emission spectrum of polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after 1.67 min of irradiation with 365 nm ultraviolet light. Figure 11b During the heating and cooling process, I 382 Normalized change curve of values; Figure 12a The fluorescence emission spectrum of polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after irradiation with 365 nm ultraviolet light for 8.33 min. Figure 12b During the heating and cooling process, I 382 Normalized change curve of values; Figure 13a The fluorescence emission spectrum of polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after 20 min of irradiation with 365 nm ultraviolet light. Figure 13b During the heating and cooling process, I 382 Normalized change curve of values; Figure 14a The fluorescence emission spectrum of polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process is as follows: after irradiation with 365 nm ultraviolet light for 20 min, irradiation was continued with 254 nm ultraviolet light for another 20 min. Figure 14b During the heating and cooling process, I 382 The normalized variation curve of the value; as can be seen from the above five sets of variation curves, by adjusting the duration of ultraviolet light irradiation, I can be controlled. 382 The trend and magnitude of the "rising-falling" value. And I 382The fluorescence emission intensity is closely related to the association state of the PVMAB segments. At low temperatures, association occurs between the molecules of the inner salt structure, forming a cross-linked polymer chain structure, which makes the PVMAB segments insoluble, resulting in a relatively high fluorescence emission peak intensity. At high temperatures, the anions of the zwitterion pairs tend to associate with the cations within the molecules, causing the PVMAB segments to partially dissolve, resulting in a relatively low fluorescence emission peak intensity.

[0093] Example 6

[0094] The solubility of polybetaine is significantly affected by the association of zwitterions in the inner salt structure. At low temperatures, intermolecular association in the inner salt structure leads to the formation of cross-linked polymer chains, making polybetaine insoluble; at high temperatures, the anions of the zwitterion pairs tend to associate intramolecularly, promoting partial dissolution of polybetaine. The phase transition behavior of PVMAB segments is as follows: Figure 15 As shown, the quaternary ammonium salt cation and the borate anion are bonded through an eight-membered ring of diethanolamine borate, causing boron to be in the form of B(OH)4. - It exists in ionic form and generates a large number of electrostatically associative zwitterion pairs. Due to the weak acidity of boric acid, the quaternary ammonium salt cation reacts with B(OH)4. - The electrostatic association between them is relatively weak. At low temperatures, B(OH)4 - Anions tend to form ion pairs with quaternary ammonium salt cations intermolecularly. Due to the ring strain within the eight-membered ring and relatively weak intramolecular association, the water solubility of PVMAB segments decreases. At high temperatures, the cross-linked network structure formed by intermolecular ion pair association is easily destroyed, and zwitterions undergo intramolecular association, causing the PVMAB segments to change from insoluble to partially soluble.

Claims

1. A method for preparing a temperature-ultraviolet light dual responsive functional polymer, characterized in that, Specifically, the following steps are implemented: Step 1, Preparation of the macroinitiator PEG2-ABCPA; the structural formula of the PEG2-ABCPA is: ; the PEG in the structural formula is: ; Step 2, preparation of p-vinylmethyl diethanolamine borate monomer VMAB; the structural formula of the VMAB is: ; Step 3, a free radical polymerization reaction is carried out using the macromolecular initiator PEG2-ABCPA, the styrylmethyl diethanolamine borate monomer VMAB and 7-(4-vinylbenzyloxy)-4-methyl coumarin VBC to obtain a block copolymer, which is a temperature-ultraviolet light dual response functional polymer.

2. The method for preparing the temperature-UV irradiation dual-responsive functional polymer as described in claim 1, characterized in that, In the step 1, specifically: Polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanopentanoic acid), 4-dimethylaminopyridine and dicyclohexyl carbodiimide were mixed, dichloromethane and N,N-dimethylformamide dried with KOH were added, stirring until completely dissolved, the reaction was continued to stir at room temperature for 20-24 h, vacuum filtration was performed, the filtrate was collected, rotary evaporation was performed, then the precipitate was precipitated with ether for 2-3 times, filtration was performed again, the precipitate was allowed to stand for 12-24 h, and after the organic solvent was completely volatilized, vacuum drying was performed to obtain the macroinitiator PEG2-ABCPA; the structural formula of polyethylene glycol monomethyl ether is: .

3. The method for preparing the temperature-UV irradiation dual-responsive functional polymer as described in claim 1, characterized in that, In the step 2, specifically: N-methyldiethanolamine, boric acid, toluene are mixed and subjected to a condensation reflux reaction, the reaction time is 10-18 h, the reaction temperature is 130-140 ℃, after the reaction is completed, it is cooled to room temperature, the remaining toluene is pumped out under reduced pressure using a water pump and an oil pump in sequence, a solid product is obtained; the obtained solid product is dissolved in acetone, then p-chloromethylstyrene is added dropwise, the temperature is slowly increased to 45-55 ℃, a condensation reflux reaction is carried out, the reflux reaction time is 2-3 h, after the reaction is stopped, it is cooled to room temperature, sodium carbonate is slowly added to the mixture after the reaction, the reaction is carried out for 2-3 h, after the reaction is stopped, it is filtered, rotary evaporated, then the product is dissolved in a mixed solvent of methanol and dichloromethane, the insoluble substances are filtered, precipitated with petroleum ether, after the petroleum ether is completely volatilized, vacuum drying is carried out, a yellow powdery solid is obtained, which is the p-styrylmethyl diethanolamine borate monomer.

4. The method for preparing the temperature-UV irradiation dual-responsive functional polymer as described in claim 3, characterized in that, The molar ratio of N-methyldiethanolamine, boric acid, p-chloromethylstyrene and sodium carbonate is 1.5-2.5:2-3:2.5-3.5:2.5-3.

5.

5. The method for preparing the temperature-UV irradiation dual-responsive functional polymer as described in claim 1, characterized in that, In the step 3, specifically: PEG2-ABCPA, VMAB and VBC are dissolved in a mixed solvent, the mixed solvent is obtained by mixing water and N,N-dimethylformamide, then it is transferred into a reactor, the reactor is repeatedly subjected to a cooling-vacuum operation three times to remove the air in the reactor, after stirring at room temperature for 30-40 min, it is placed in a 75-85 ℃ oil bath for stirring reaction, the reaction time is 30-40 h, after the reaction is completed, it is cooled to room temperature, filtered, the filtrate is precipitated with diethyl ether as a precipitant, then the precipitate is dissolved in a mixed solvent of water and DMF, is loaded into a dialysis bag, the deionized water is changed every 3 h, dialysis is carried out for three days, vacuum freeze-drying is carried out, the target polymer, which is a temperature-ultraviolet light dual response functional polymer, is obtained.

6. The method for preparing the temperature-UV irradiation dual-responsive functional polymer as described in claim 5, characterized in that, The molar ratio of PEG2-ABCPA, VMAB and VBC is 3-5:95-105:5-7.

7. The functional polymer prepared by the preparation method of the temperature-ultraviolet light dual response functional polymer according to any one of claims 1-6.

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