Temperature-ultraviolet illumination dual response type functional polymer and preparation method thereof

Abstract

The invention discloses a preparation method of a temperature-ultraviolet illumination dual response type functional polymer. The preparation method specifically comprises the following steps: preparing a macromolecular initiator PEG2-ABCPA; preparing a p-styryl methyl diethanolamine borate monomer VMAB (vinyl methyl amine borate); the preparation method comprises the following steps: carrying out a free radical polymerization reaction on a styryl methyldiethanolamine borate monomer VMAB and 7-(4-vinylbenzyloxy)-4-methylcoumarin VBC by using a macromolecular initiator PEG2-ABCPA to obtain a block copolymer, namely the temperature-ultraviolet irradiation dual response type functional polymer. The polymer not only has a unique amphiphilic property, but also shows dual responsiveness to temperature and ultraviolet irradiation, so that the polymer shows a wide application prospect in the fields of drug controlled release, intelligent materials, photoelectric devices and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer preparation, and in particular relates to a method for preparing a temperature-ultraviolet light dual-responsive functional polymer, and also relates to the temperature-ultraviolet light dual-responsive functional polymer. Background Art

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

[0003] Polyethylene glycol (PEG) is a commonly used hydrophilic polymer material. Due to its good water solubility, biocompatibility and chemical stability, it has become an ideal hydrophilic segment for constructing amphiphilic block copolymers. However, a single PEG segment is usually difficult 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 hot topic and difficulty in current research.

[0004] In the existing research technology, there are several shortcomings in the synthesis and application of amphiphilic block copolymers. First, the amphiphilic block copolymers prepared by traditional methods often have a single function and are difficult to meet the complex and changeable application requirements. Especially in cutting-edge fields such as drug delivery, tissue engineering and nanotechnology, higher requirements are placed on the structure and performance of materials, and traditional materials often cannot simultaneously meet multiple performance requirements such as hydrophilicity, hydrophobicity, biocompatibility, and responsiveness. Secondly, when preparing amphiphilic block copolymers, there are often problems such as cumbersome synthesis steps, low yield, and difficult purification. This not only increases production costs, but also limits the wide application of materials. For example, some traditional synthesis methods require the use of toxic and harmful solvents or catalysts, which pollute the environment and may also have a negative impact on the biocompatibility of the material. Summary of the invention

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

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

[0007] The technical solution adopted by the present invention is a method for preparing a temperature-ultraviolet light dual-responsive functional polymer, which is specifically implemented according to the following steps:

[0008] Step 1, prepare the macromolecular initiator PEG 2 -ABCPA; specifically:

[0009] Step 2, prepare the styrylmethyldiethanolamine borate monomer VMAB;

[0010] Step 3, use the macromolecular initiator PEG 2 -ABCPA, the styrylmethyldiethanolamine borate monomer VMAB and 7-(4-vinylbenzyloxy)-4-methylcoumarin VBC to carry out a radical polymerization reaction to obtain a block copolymer, which is a temperature-ultraviolet light dual-responsive functional polymer.

[0011] The characteristics of the present invention also lie in that

[0012] In Step 1, specifically:

[0013] Mix methoxypolyethylene glycol, 4,4-azobis(4-cyanovaleric acid), 4-dimethylaminopyridine and dicyclohexylcarbodiimide, add dichloromethane and N,N-dimethylformamide dried with KOH, stir until completely dissolved, continue to stir and react at room temperature for 20-24 h, carry out suction filtration under reduced pressure, collect the filtrate, rotary evaporate, then precipitate with ether 2-3 times, carry out suction filtration again, let the precipitate stand for 12-24 h, and vacuum dry after the organic solvent has completely volatilized to obtain the macromolecular initiator PEG 2 -ABCPA.

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

[0015] In Step 2, specifically:

[0016] Mix N-methyldiethanolamine, boric acid and toluene, carry out a condensation reflux reaction, the reaction time is 10-18 h, the reaction temperature is 130-140 °C, after the reaction is completed, cool to room temperature, and sequentially pump off the remaining toluene with a water pump and an oil pump to obtain a solid product; dissolve the obtained solid product in acetone, then dropwise add p-chloromethylstyrene, slowly raise the temperature to 45-55 °C, carry out a condensation reflux reaction, the reflux reaction time is 2-3 h, after the reaction stops, cool to room temperature, slowly add sodium carbonate to the reaction mixture, react for 2-3 h, after the reaction stops, carry out suction filtration, rotary evaporate, then dissolve the product with a mixed solvent of methanol and dichloromethane, filter the insoluble matter, precipitate with petroleum ether, and vacuum dry after the petroleum ether has completely volatilized to obtain a yellow powdery solid, which is the styrylmethyldiethanolamine borate monomer.

[0017] 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.

[0018] In step 3, specifically:

[0019] Dissolve PEG 2 -ABCPA, VMAB, and VBC in a mixed solvent composed of water and N,N-dimethylformamide. Then transfer it to a reactor, and repeat the cooling-vacuum operation on the reactor three times to remove all the air in the reactor. After stirring at room temperature for 30 - 40 min, place it in an oil bath at 75 - 85 °C for stirring reaction. The reaction time is 30 - 40 h. After the reaction is completed, cool it to room temperature, filter, precipitate the filtrate with ether as the precipitant, then dissolve the precipitate in a mixed solvent of water and DMF, put it into a dialysis bag, change the deionized water every 3 h, dialyze for three days, and vacuum freeze-dry to obtain the target polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ), which is a temperature-ultraviolet light dual-responsive functional polymer.

[0020] The molar ratio of PEG 2 -ABCPA, VMAB, and VBC is 3 - 5: 95 - 105: 5 - 7.

[0021] Another technical solution adopted by the present invention is a functional polymer prepared by the preparation method of the temperature-ultraviolet light dual-responsive functional polymer.

[0022] The beneficial effect of the present invention is that: by the method of the present invention, first, a macromolecular initiator PEG 2 -ABCPA is synthesized through a specific chemical reaction. This initiator not only contains a PEG segment but also introduces ABCPA (4,4-azobis(4-cyanovaleric acid)) as an active center, providing the possibility for subsequent radical polymerization reactions. Subsequently, using PEG 2 -ABCPA as a macromolecular initiator, through radical polymerization reaction, the monomers 7-(4-vinylbenzyloxy)-4-methylcoumarin (VBC) and p-styrylmethyldiethanolamine borate (VMAB) are grafted onto the PEG segment to form PEO 45 -b-P(VBC 2 -co-VMAB 9 ) block copolymer. This polymer not only has unique amphiphilic properties but also exhibits dual responsiveness to temperature and ultraviolet light, thus showing broad application prospects in the fields of drug controlled release, intelligent materials, optoelectronic devices, etc. Description of the Drawings

[0023] Figure 1 is the macromolecular initiator PEG 2 - Preparation process diagram of ABCPA;

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

[0025] Figure 3 is the preparation process diagram of p-styryl-N-methyldiethanolamine borate;

[0026] Figure 4 is the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 )'s preparation process diagram;

[0027] Figure 5 is of p-styryl-N-methyldiethanolamine borate 1 H NMR spectrum;

[0028] Figure 6 is the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 )'s 1 H NMR spectrum;

[0029] Figure 7a is of the polymer PEO with different concentrations 45 -b-P(VBC 2 -co-VMAB 9 ) in the pyrene-saturated aqueous solution's fluorescence emission spectrum diagram;

[0030] Figure 7b is I 1 / I 3 value's change curve diagram with the polymer solution concentration;

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

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

[0033] Figure 8c is the normalized change curve diagram of the I 320 value with the continuation of the illumination time;

[0034] Figure 9a is the fluorescence emission spectrum diagram of the polymer micelles under 365nm UV light illumination;

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

[0036] Figure 9c It is the normalized change curve of the I 382 value with the continuation of the irradiation time;

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

[0038] Figure 10b It is the I 382 value during the heating and cooling process

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

[0040] Figure 11b It is the I 382 value during the heating and cooling process after irradiation with 365 nm ultraviolet light for 1.67 min;

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

[0042] Figure 12b It is the I 382 value during the heating and cooling process after irradiation with 365 nm ultraviolet light for 8.33 min;

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

[0044] Figure 13b It is the I 382 value during the heating and cooling process after irradiation with 365 nm ultraviolet light for 20 min

[0045] Figure 14a It is the fluorescence emission spectrum of polymer micelles during the heating and cooling process after irradiation with 365 nm ultraviolet light for 20 min and then continuing to irradiate with 254 nm ultraviolet light for 20 min;

[0046] Figure 14b It is the I 382 value during the heating and cooling process after irradiation with 365 nm ultraviolet light for 20 min and then continuing to irradiate with 254 nm ultraviolet light for 20 min;

[0047] Figure 15It is a schematic diagram of the phase transition between molecules and within molecules of borate quaternary ammonium salt ion pairs during heating and the phase transition of PVMAB chain segments during heating and cooling. DETAILED DESCRIPTION

[0048] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] The preparation method of the temperature-ultraviolet light dual-responsive functional polymer of the present invention is specifically implemented according to the following steps:

[0050] Step 1, preparation of macromolecular initiator PEG 2 -ABCPA; specifically:

[0051] Polyethylene glycol monomethyl ether (PEG), 4,4-azobis(4-cyanovaleric acid) (ABCPA), 4-dimethylaminopyridine (DMAP) and dicyclohexylcarbodiimide (DCC) were mixed, dichloromethane and N,N-dimethylformamide dried with KOH were added, magnetic stirring was performed until completely dissolved, stirring and reacting were continued at room temperature for 20-24 hours, the reaction solution was filtered under reduced pressure using a Buchner funnel, the filtrate was collected, the precipitate was poured out (unreacted monomers, initiators, catalysts and other impurities were removed), the filtrate was rotary evaporated at 30°C using a rotary evaporator to remove impurity solvents, and then ether was used for precipitation 2-3 times (the volume ratio of ether to filtrate was 20:1), and suction was filtered again. The precipitate was allowed to stand for 12-24 hours, and after the organic solvent was completely evaporated, vacuum dried for 12 hours to obtain the macromolecular initiator PEG. 2 -ABCPA;

[0052] The molar ratio of polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanovaleric 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, preparing p-phenylvinylmethyldiethanolamine borate monomer (VMAB); specifically:

[0054] N-methyldiethanolamine, boric acid and toluene are mixed and subjected to condensation reflux reaction. The reflux reaction time is 10-18 hours and the reflux reaction temperature is 130-140°C. The water brought out by toluene during the reaction is continuously released. After the reaction is completed, the mixture is cooled to room temperature. The remaining toluene in the flask is removed by decompression using a water pump and an oil pump in turn to obtain a light 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 °C for condensation reflux reaction. The reflux reaction time was 2 - 3 h. After the reaction stopped, it was cooled to room temperature. Sodium carbonate was slowly added to the reaction mixture and reacted for 2 - 3 h to remove the chloride ions in p-chloromethylstyrene, forming a borate quaternary ammonium salt. After the reaction stopped, sodium carbonate was removed by suction filtration, and the acetone solvent was removed by rotary evaporation. Then the product was dissolved in a mixed solvent of methanol and dichloromethane (volume ratio 1:1), the insoluble substances were filtered out, and it was precipitated with petroleum ether 3 times. After the petroleum ether completely volatilized, it was dried under vacuum to obtain a yellow powdery solid, which was the styryl methyl diethanolamine borate monomer (VMAB);

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

[0057] Step 3, using the macromolecular initiator PEG 2 -ABCPA, styryl methyl diethanolamine borate monomer and 7-(4-vinylbenzyloxy)-4-methylcoumarin VBC were subjected to a radical polymerization reaction to obtain a block copolymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ); Specifically:

[0058] Taking PEG 2 -ABCPA as the macromolecular initiator, selecting VMAB as the hydrophilic monomer and VBC as the hydrophobic monomer, dissolving PEG 2 -ABCPA, VMAB, and VBC in a mixed solvent (the mixed solvent was composed of water and N,N-dimethylformamide with a volume ratio of 3:5), then transferring it to a reactor, repeating the cooling-vacuuming operation on the reactor three times to remove all the air in the reactor. After stirring at room temperature for 30 - 40 min, it was placed in an oil bath at 75 - 85 °C for stirring reaction. The reaction time was 30 - 40 h. After the reaction ended, it was cooled to room temperature, and the yellow viscous precipitate was removed by filtration to obtain an orange-red filtrate. It was precipitated 3 times with ether as the precipitating agent, and then the precipitate was dissolved in a mixed solvent of a small amount of water and DMF, filled into a dialysis bag (Mw = 3500 g / mol), and the deionized water was changed every 3 h for dialysis for three days. Finally, the obtained substance was freeze-dried under vacuum to obtain the target polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ), which was a temperature-ultraviolet light dual-responsive functional polymer;

[0059] PEG 2-The molar ratio of ABCPA, VMAB, and VBC is 3 - 5:95 - 105:5 - 7;

[0060] The present invention successfully combines monomers such as polyethylene glycol (PEG), p-styrylmethyldiethanolamine borate (VMAB), and 7-(4-vinylbenzyloxy)-4-methylcoumarin (VBC) monomers to synthesize a novel polymer with temperature and ultraviolet light sensitivity. This polymer not only has simple synthesis steps, but also high yield and easy purification, providing the possibility for large-scale production and wide application.

[0061] In addition, the present invention also explores the 45 -b-P(VBC 2 -co-VMAB 9 ) block copolymer self-assembly behavior in aqueous solution, and prepares a uniform aqueous solution of polymer micelles by direct dissolution method. Using a fluorescence spectrophotometer to study the chemical environment of coumarin in the polymer micelle solution, it is found that this polymer can spontaneously form a stable micelle structure in aqueous solution, and the coumarin group exhibits specific fluorescence properties inside the micelle, providing important theoretical basis and experimental support for the application of polymer micelles.

[0062] Example 1

[0063] The preparation method of the temperature-ultraviolet light dual-responsive functional polymer of the present invention is specifically implemented according to the following steps:

[0064] Step 1, prepare the macromolecular initiator PEG 2 -ABCPA; specifically:

[0065] As Figure 1 shown, 0.04 mmol of methoxypolyethylene glycol (PEG), 4,4-azobis(4-cyanovaleric acid) (ABCPA), 0.02 mmol of 4-dimethylaminopyridine (DMAP), and 0.006 mmol of dicyclohexylcarbodiimide (DCC) are mixed, 90 mL of dichloromethane and N,N-dimethylformamide dried with KOH are added, and magnetically stirred until completely dissolved. The reaction is continued to stir at room temperature for 24 h. The reaction solution is filtered under reduced pressure with a Buchner funnel, the filtrate is collected, and the precipitate is discarded (removing unreacted monomers, initiators, catalysts and other impurities). The filtrate is rotary evaporated at 30 °C using a rotary evaporator to remove the impurity solvent, and then precipitated with ether twice (the volume ratio of ether to the filtrate is 20:1). It is filtered again, the precipitate is left standing for 12 h, and after the organic solvent has completely evaporated, it is dried in vacuo for 12 h to obtain the macromolecular initiator PEG 2 -ABCPA;

[0066] Through a specific chemical reaction, the macromolecular initiator PEG was successfully synthesized2 -ABCPA. This initiator plays a crucial role in the subsequent polymerization reaction and provides the basis for the synthesis of block copolymers. After removing the impurity solvents by a rotary evaporator, ether precipitation, vacuum drying and other steps, the yield of the finally obtained macromolecular initiator is 85.87%, with a relatively high purity, providing high-quality raw materials for the subsequent reaction.

[0067] Step 2: Prepare p-styrylmethyldiethanolamine borate monomer (VMAB); specifically:

[0068] As Figure 2 shown, 0.75 mol of N-methyldiethanolamine, 0.97 mol of boric acid and 200 mL of toluene are mixed and subjected to a condensation reflux reaction. The reflux reaction time is 12 h, and the reflux reaction temperature is 140 °C. The water carried out by toluene during the reaction is continuously discharged. After the reaction is completed, it is cooled to room temperature, and the remaining toluene in the flask is removed by decompression pumping with a water pump and an oil pump in turn to obtain a light yellow solid product;

[0069] The obtained solid product is dissolved in 200 mL of acetone, then 1.125 mol of p-chloromethylstyrene is added dropwise, and the temperature is slowly raised to 50 °C for a condensation reflux reaction. The reflux reaction time is 2 h. After the reaction stops, it is cooled to room temperature. 1.125 mol of sodium carbonate is slowly added to the reaction flask, and the reaction is carried out for 2 h to remove the chloride ions in p-chloromethylstyrene to form a borate quaternary ammonium salt. After the reaction stops, sodium carbonate is removed by filtration, the acetone solvent is removed by rotary evaporation, and the product is dissolved in a mixed solvent of methanol and dichloromethane (volume ratio 1:1), the insoluble substances are filtered out, and it is precipitated with petroleum ether 3 times. After the petroleum ether has completely volatilized, it is vacuum dried to obtain a yellow powdery solid, which is p-styrylmethyldiethanolamine borate monomer (VMAB), as Figure 3 shown;

[0070] Through two-step chemical reactions, p-styrylmethyldiethanolamine borate monomer (VMAB) is successfully synthesized. This monomer has a unique chemical structure and properties and is an important component of the final block copolymer PEO 45 -b-P(VMAB 9 -co-VBC 2 ). After steps such as dissolution in a mixed solvent of methanol and dichloromethane, filtration, precipitation with petroleum ether, vacuum drying, etc., the finally obtained yield of VMAB is 80%, with a relatively high purity, providing reliable raw materials for the subsequent reaction. 1 H NMR(400MHz,D 2 O)δ(ppm):7.4&7.3(d,4H,Ar-H),6.7(t,1H,ArCH=),5.8(dd,1H,CH 2 =),5.3(d,1H,CH2 =), 4.5 (s, 2H, ArCH 2 -), 4.0 - 3.9 (t, 4H, -CH 2 O-), 3.5 - 3.3 (tt, 4H, -NCH 2 -), 2.9 (s, 3H, CH 3 -);

[0071] Step 3, prepare the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ), specifically:

[0072] As Figure 4 shown, dissolve 0.51 mmol of PEG 2 -ABCPA, 12.69 mmol of VMAB, and 0.76 mmol of VBC in a mixed solvent (the mixed solvent is composed of water and N,N-dimethylformamide with a volume ratio of 3:5), then transfer it to a reactor. Repeat the cooling-vacuum operation on the reactor three times to remove all the air in the reactor. After stirring at room temperature for 30 min, place it in an oil bath at 78 °C for stirring reaction. The reaction time is 36 h. After the reaction is completed, cool it to room temperature, filter to remove the yellow viscous precipitate to obtain an orange-red filtrate. Precipitate it 3 times with ether as the precipitant, then dissolve the precipitate in a small amount of mixed solvent of water and DMF, load it into a dialysis bag (Mw = 3500 g / mol), change the deionized water every 3 h, dialyze for three days, and finally vacuum freeze-dry the obtained substance to obtain the block copolymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ), which is a temperature-ultraviolet light dual-responsive functional polymer with a yield of 76%; 1 H NMR (400 MHz, D 2 O) δ (ppm): 8.0 - 5.7 (m, Ar-H), 5.1 (s, -CH 2 O-for VBC), 4.5 (s, ArCH 2 -for VMAB), 4.2 - 3.8 (s, -CH 2 O-B<), 3.8 - 3.1 (m, -CH 2 OC H 2 -forPEG&-NCH 2 -), 2.9 (s, >N-CH 3 ), 2.5 - 0.5 (m, -CH 3 &-CH 3 );

[0073] Due to the differences in the water solubility of polymer segments, the main methods for preparing micelles are dialysis method and direct dissolution method. PEO 45 -b-P(VBC 2 -co-VMAB 9 ) has a relatively long hydrophilic segment and good water solubility, and can be directly dissolved in water to prepare micelles. Weigh 80 mg of the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ) and directly dissolve it in ultrapure water. After stirring at a constant speed for 12 h, a homogeneous aqueous solution of polymer micelles is prepared, and the micelle concentration is 10 mg / mL at this time. The micellization behavior of the polymer is studied using a fluorescence spectrophotometer.

[0074] Using PEG 2 -ABCPA as a macromolecular initiator, VMAB as a hydrophilic monomer, and VBC as a hydrophobic monomer, the block copolymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ) is successfully synthesized by free radical polymerization. This copolymer has unique amphiphilic properties and temperature and ultraviolet light responsiveness, and has broad application prospects in the fields of drug delivery, tissue engineering, etc. After steps such as ether precipitation, dialysis, and vacuum freeze-drying, the final polymer yield is 44.35%, with a relatively high purity, providing a high-quality material basis for subsequent application research.

[0075] Example 2

[0076] 1 1H NMR Spectral Analysis

[0077] To determine that the synthesized polymer is the target product PEO 45 -b-P(VBC 2 -co-VMAB 9 ), the synthesized substance, intermediate product (monomer VMAB), etc. of the present invention are subjected to 1 1H NMR spectral analysis, and the results are as follows:

[0078] Figure 5 This is the 1 1H NMR spectrum of monomer VMAB (the solvent is D 2 2O). Among them, the hydrogens at 7.4, 7.3, 6.7, 5.8, and 5.3 ppm all belong to the hydrogens on the benzene ring, and the integral ratio is 2 / 2 / 1 / 1 / 1; the hydrogen at 4.5 ppm belongs to -CH 2 connected to the benzene ring; the hydrogen proton signals are at 4.0 - 3.9 and 3.5 - 3.3 ppm, which are -CH 2Hydrogen on it; the hydrogen proton signal observed at 2.9 ppm is the -CH in the quaternary ammonium salt 3 hydrogen on it. Figure 6 is the 1 1H NMR spectrum of the target polymer. Among them, hydrogen proton peaks of the benzene ring appear in the range of 5.7 - 8.0 ppm, and the singlet at 4.5 ppm belongs to the -CH 2 - hydrogen proton characteristic peak connected to the benzene ring in the structure of p-styrylmethyldiethanolamine borate. The multiple absorption peaks in the range of 3.8 - 4.2 ppm are the -CH 2 OCH 2 - hydrogen proton peaks in the PEO chain segment of the macroinitiator and the -NCH 2 - hydrogen on it. According to the integral peak area ratio of these three characteristic peaks, it is calculated that the polymer contains 2 VBC monomer units and 9 VMAB monomer units respectively. The target polymer can be labeled as PEO 45 -b-P(VBC 2 -co-VMAB 9 ).

[0079] Example 3

[0080] Performance Characterization of Polymer Micelles

[0081] Before systematically studying the micelles formed by the target polymer, the CMC value of this polymer was first determined by the pyrene probe technique. As Figure 7a shown, it is the fluorescence emission spectrum of a pyrene-saturated aqueous solution containing different polymer concentrations. It can be clearly seen that in the wavelength range of 350 - 550 nm, there is a five-finger characteristic absorption peak band of pyrene, and the intensity changes continuously with the change of the polymer solution concentration. Figure 7b Summarized the correlation curve of the ratio of fluorescence intensities at 373 nm (I 1 ) and 384 nm (I 3 ) in the five-finger absorption peak band with the change of polymer solution concentration. When the polymer concentration is lower than 1.67×10 -3 mg / mL, the I 1 / I 3 value hardly changes; while when the polymer concentration gradually increases to 1.67×10 -3 mg / mL, the I 1 / I 3 value mutates and rapidly decreases. This change indicates that polymer molecules begin to form micelle aggregates from the dispersed free state, and pyrene molecules also gradually enter the hydrophobic core of the polymer micelles from the aqueous solution. Thus, it can be determined that the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9)The CMC value in aqueous solution is 1.67×10 -3 mg / mL.

[0082] Example 4

[0083] Photoresponsive behavior of polymer micelles under combined light irradiation

[0084] First, the ultraviolet-visible absorption spectrum of the obtained polymer micelles (PM) was characterized and analyzed. As Figure 8a shown, PM exhibits a shoulder-like characteristic absorption peak in the wavelength range of 280 - 380 nm. With the accumulation of the irradiation time of 365 nm (80 mW / cm 2 ) ultraviolet light, the intensity of this characteristic absorption peak significantly decreases. This is due to the [2+2] cycloaddition reaction of the coumarin moiety. Figure 8b Figure shows the ultraviolet-visible absorption spectrum change diagram after irradiating the polymer micelles with 365 nm ultraviolet light for 20 min and then continuing to irradiate the micelles with 254 nm (8 mW / cm 2 ) ultraviolet light. It can be seen that the shoulder peak in the wavelength range of 280 - 380 nm slowly rises. This is because the dissociation behavior of the coumarin dimer under 254 nm ultraviolet light irradiation shows a significant photoresponse correlation with its ultraviolet-visible absorption spectrum change. This phenomenon stems from the reverse [2+2] cycloaddition dissociation mechanism of the coumarin dimer. At the same time, the molar extinction coefficient of the free aromatic ring in the monomer structure is significantly enhanced, directly manifested as the increase in the intensity of the characteristic absorption peak in the range of 300 - 350 nm. This light-controlled reversible behavior reveals the molecular mechanism of wavelength-selective regulation of the dimer-monomer dynamic equilibrium, providing a key basis for optimizing the dynamic performance of photoresponsive materials.

[0085] To more clearly observe and compare the change degree of this characteristic absorption peak during the irradiation with 365 / 254 nm combined ultraviolet light, Figure 8c the normalized change curve of the ultraviolet absorbance value (I 320 ) at a wavelength of 320 nm was summarized. It can be seen from this that irradiating the polymer micelles with a single 365 nm ultraviolet light can cause a more drastic exponential change in the I 320 value than a single 254 nm ultraviolet light. This phenomenon stems from the kinetic differences of the photochemical reactions of the coumarin moiety induced by 365 nm and 254 nm ultraviolet light and the photon energy matching characteristics.

[0086] The reversible photodimerization reaction process of the coumarin moiety in PM was analyzed and explained through the change of the fluorescence emission spectrum during the irradiation process. As Figure 9a 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); The micelles were cumulatively irradiated with 365 nm ultraviolet light for 1.67 min, and the intensity of this characteristic peak continuously increased; continued light stimulation was applied to it (the cumulative irradiation time reached 20 min), and the I 382 value showed a certain degree of decrease. This is because within 0 - 1.67 min of light irradiation, the coumarin moieties in the hydrophobic chain segments of the polymer underwent photodimerization reactions, resulting in crosslinking and entanglement between the polymer chains, an increase in the crosslinking density of the micelle core, a more compact aggregation of the micelle morphology, and an increase in fluorescence intensity. However, during this photocrosslinking process, more and more coumarin units formed coumarin dimers, which caused the proportion of the relatively less - contained VBC component in the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ) to decrease significantly in the entire polymer micelle. Therefore, when the micelles were continuously irradiated with 365 nm ultraviolet light, the fluorescence intensity showed a certain degree of downward trend.

[0087] Subsequently, the polymer micelles were irradiated with 254 nm ultraviolet light ([ Figure 9b ), and the intensity of this fluorescence emission characteristic peak showed a trend of first increasing and then decreasing again, and the "increase - decrease" amplitude was significantly weaker than the photo - responsiveness change induced by 365 nm ultraviolet light. The main reason for this change is that a small part of the coumarin dimers can undergo photodissociation reactions under 254 nm light irradiation, resulting in a small increase in I 382 ; while exposed to longer - time 254 nm ultraviolet light irradiation, the dissociated coumarin units underwent irreversible photodimerization reactions again, causing the I 382 value to decrease.

[0088] The above research results show that: by adjusting the combined ultraviolet light irradiation time, the instant regulation of the photo - response performance of the hydrophobic chain segment components of the polymer can be achieved.

[0089] Example 5

[0090] Thermosensitive characteristic behavior of polymer micelles when the temperature changes

[0091] For the aqueous solution of the polymer PEO 45 -b-P(VBC 2 -co-VMAB 9 ) micelles under single 365 nm and combined ultraviolet light irradiation for different durations, fluorescence emission spectral tracking tests were carried out, and the fluorescence intensity (I 382 ) at a wavelength of 382 nm in the spectrum was also analyzed and discussed; Figure 10a is the fluorescence emission spectrum of the polymer micelles (1.5 mg / mL×1.5 mL) during the heating - cooling process before light irradiation; Figure 10b is during the heating - cooling process, I382 Normalized change curve of the value;

[0092] Figure 11a It is the fluorescence emission spectrum of the polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after being irradiated with 365 nm ultraviolet light for 1.67 min; Figure 11b During the heating and cooling process, I 382 Normalized change curve of the value; Figure 12a It is the fluorescence emission spectrum of the polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after being irradiated with 365 nm ultraviolet light for 8.33 min; Figure 12b During the heating and cooling process, I 382 Normalized change curve of the value; Figure 13a It is the fluorescence emission spectrum of the polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after being irradiated with 365 nm ultraviolet light for 20 min; Figure 13b During the heating and cooling process, I 382 Normalized change curve of the value; Figure 14a It is the fluorescence emission spectrum of the polymer micelles (1.5 mg / mL × 1.5 mL) during the heating and cooling process after being irradiated with 365 nm ultraviolet light for 20 min and then continuing to irradiate with 254 nm ultraviolet light for 20 min; Figure 14b During the heating and cooling process, I 382 Normalized change curve of the value; It can be seen from the above five groups of change curves that by regulating the irradiation duration of ultraviolet light, the "rise - fall" change trend and amplitude of the I 382 value can be regulated. And the I 382 value is closely related to the association state of the PVMAB chain segment. At low temperature, intermolecular association occurs in the inner salt structure, forming a cross - linked network polymer chain structure, resulting in the insolubility of the PVMAB chain segment, so the measured fluorescence emission peak intensity is relatively high; while at high temperature, the anions of the zwitterionic pairs tend to associate with the cations within the molecule, leading to partial dissolution of the PVMAB chain segment at high temperature, so the measured fluorescence emission peak intensity is relatively low.

[0093] Example 6

[0094] The solubility of polybetaine is significantly affected by the association of zwitterionic pairs in the inner salt structure. At low temperature, intermolecular association of the inner salt structure leads to the formation of a cross - linked network polymer chain, making polybetaine insoluble; at high temperature, the anions of the zwitterionic pairs tend to associate within the molecule, promoting partial dissolution of polybetaine. The phase transition behavior of the PVMAB chain segment is as Figure 15 shown, in which the quaternary ammonium salt cation and the borate anion are bonded through an eight - membered ring of diethanolamine borate, making boron in the form of B(OH) 4 -exist in ionic state and generate a large number of zwitterionic pairs that can be electrostatically associated. Due to the weak acidity of boric acid, the electrostatic association between the quaternary ammonium salt cation and B(OH) 4 - is relatively weak. At low temperatures, the B(OH) 4 - anion tends to form ion pairs with the quaternary ammonium salt cation intermolecularly. Affected by the internal ring tension of the eight-membered ring and the relatively weak intramolecular association, the water solubility of the PVMAB segment decreases. At high temperatures, the cross-linked network structure formed by intermolecular ion pair association is easily destroyed, and the zwitterions undergo intramolecular association, resulting in the PVMAB segment changing from insoluble to partially soluble.

Claims

1. A method for preparing a temperature-ultraviolet light dual-responsive functional polymer, characterized in that: Follow the steps below to implement it: Step 1, preparing a macromolecular initiator PEG2-ABCPA; Step 2, preparing p-phenylvinylmethyldiethanolamine borate monomer VMAB; Step 3, using the macromolecular initiator PEG2-ABCPA, the p-phenylmethyldiethanolamine borate monomer VMAB and the 7-(4-vinylbenzyloxy)-4-methylcoumarin VBC to carry out a free radical polymerization reaction to obtain a block copolymer, which is a temperature-ultraviolet light dual-responsive functional polymer.

2. The method for preparing a temperature-ultraviolet light dual-responsive functional polymer according to claim 1, characterized in that: In the step 1, specifically: Mix polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanovaleric acid), 4-dimethylaminopyridine and dicyclohexylcarbodiimide, add dichloromethane and N,N-dimethylformamide dried with KOH, stir until completely dissolved, continue to react with stirring at room temperature for 20-24 hours, filter under reduced pressure, collect the filtrate, rotary evaporate, then precipitate with ether 2-3 times, filter again, let the precipitate stand for 12-24 hours, and vacuum dry after the organic solvent is completely evaporated to obtain the macromolecular initiator PEG2-ABCPA.

3. The method for preparing the temperature-ultraviolet light dual-responsive functional polymer according to claim 2, characterized in that: The molar ratio of polyethylene glycol monomethyl ether, 4,4-azobis(4-cyanovaleric acid), 4-dimethylaminopyridine and dicyclohexylcarbodiimide is 1.5-2.5: 0.5-1.5: 2.5-3.5: 2.5-3.

5.

4. The method for preparing a temperature-ultraviolet light dual-responsive functional polymer according to claim 1, characterized in that: In the step 2, specifically: N-methyldiethanolamine, boric acid and toluene are mixed and subjected to condensation reflux reaction. The reaction time is 10-18 hours and the reaction temperature is 130-140°C. After the reaction is completed, the mixture is cooled to room temperature. The remaining toluene is removed by decompression with a water pump and an oil pump in turn to obtain a solid product. The obtained solid product is dissolved in acetone, and then p-chloromethylenestyrene is added dropwise. The temperature is slowly raised to 45-55°C and subjected to condensation reflux reaction. The reflux reaction time is 2-3 hours. After the reaction stops, the mixture is cooled to room temperature. Sodium carbonate is slowly added to the mixture after the reaction and the reaction is carried out for 2-3 hours. After the reaction stops, the mixture is filtered and rotary evaporated. The product is dissolved in a mixed solvent of methanol and dichloromethane. The insoluble matter is filtered and precipitated with petroleum ether. After the petroleum ether is completely evaporated, the mixture is vacuum dried to obtain a yellow powdery solid, which is p-phenylvinylmethyldiethanolamine borate monomer.

5. The method for preparing the temperature-ultraviolet light dual-responsive functional polymer according to claim 4, characterized in that: 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.

6. The method for preparing the temperature-ultraviolet light dual-responsive functional polymer according to claim 1, characterized in that: In the step 3, specifically: PEG2-ABCPA, VMAB and VBC were dissolved in a mixed solvent, which was a mixture of water and N,N-dimethylformamide. The mixed solvent was then transferred to a reactor, and the reactor was cooled and vacuumed three times to remove the air in the reactor. After stirring at room temperature for 30-40 minutes, the reactor was placed in an oil bath at 75-85°C for stirring reaction for 30-40 hours. After the reaction was completed, the reactor was cooled to room temperature and filtered. The filtrate was precipitated with ether as a precipitant. The precipitate was dissolved with a mixed solvent of water and DMF, and placed in a dialysis bag. Deionized water was replaced every 3 hours. The reactor was dialyzed for three days and vacuum freeze-dried to obtain the target polymer PEO. 45 -bP(VBC2-co-VMAB9) is a temperature-ultraviolet light dual responsive functional polymer.

7. The method for preparing a temperature-ultraviolet light dual-responsive functional polymer according to claim 6, characterized in that: The molar ratio of PEG2-ABCPA, VMAB, and VBC is 3-5:95-105:5-7.

8. The functional polymer prepared by the method for preparing a temperature-ultraviolet light dual-responsive functional polymer as described in any one of claims 1 to 7.

Images