A high fluorescence quantum yield fullerene C 60 Polymer preparation methods

Abstract

This invention discloses a high fluorescence quantum yield fullerene C 60 A method for preparing a polymer includes the following steps: taking a certain mass of C... 60 The solution was ultrasonically dispersed in an aqueous solution of N-methylpyrrolidone. The suspension was then transferred to a supercritical reactor, heated to 80-200°C, and CO2 was introduced into the reactor at 8-20 MPa. The reactor was magnetically stirred for 2-8 hours. After natural cooling to room temperature, the CO2 was slowly released to depressurize the solution. The supercritical suspension was then centrifuged to obtain C. 60 The polymer dispersion, after further purification by rotary evaporation and lyophilization, yields C. 60 Polymer powder. The C prepared in this invention... 60 The polymer disperses well in water; the preparation process is simple, with yields exceeding 50%; it exhibits stable structure, uniform size, and a wide tunable range, from a minimum of 1.4 nm to a maximum of 200 nm; it possesses dual blue-green light emission properties and high fluorescence quantum yield. This C... 60 The preparation of polymers enables the production of C 60 Starting from molecules, it becomes possible to construct other novel carbon structures, which also further enhances the application value of fullerenes in the fields of biomedicine and materials science.

Description

Technical Field

[0001] This invention relates to a high fluorescence quantum yield fullerene polymer and its preparation method. Background Technology

[0002] Spherical fullerene C 60 These are continuous, closed conjugated π systems, a class of all-carbon molecules with unique structures and outstanding photoelectric properties. Research on C... 60 The fluorescence properties of fullerenes are of great significance for the development of novel photosensitive and luminescent materials. However, I h The high symmetry of the point group makes C 60 The fluorescence quantum yield of solids at room temperature is very low (10⁻⁶). -4 The fluorescence emission intensity is extremely weak and completely invisible to the naked eye. Currently, for C... 60 Techniques for improving fluorescence performance often utilize organic solvent molecules with lone pairs of electrons or strong conjugated π bonds to interact with C. 60 To achieve strong interactions, C is reduced by introducing functional groups. 60 Molecular symmetry enhances its fluorescence yield.

[0003] For example, Chinese invention patent (CN108690602A) significantly enhances the fluorescence properties of fullerenes by introducing fluorescent building blocks onto fullerenes to prepare fullerene aziridine fluorescent derivatives. Chinese invention patent (CN101434576A) further enhances the fluorescence properties of fullerenes by introducing fluorescent building blocks onto fullerenes. 60 Silver particles are attached to the surface to enhance the fluorescence properties of fullerenes. Currently, there are no specific methods for treating fullerene C... 60 Reports on technologies that enhance the fluorescence properties of molecules themselves. Summary of the Invention

[0004] The purpose of this invention is to provide a method for controllable control of fullerene C under mild conditions using supercritical fluid technology. 60 Molecular polymerization was used to prepare pure fullerene C with strong fluorescence quantum yield. 60 polymer.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A high fluorescence quantum yield fullerene C 60 The polymer and its preparation method include the following steps:

[0007] C 60 The mixture was ultrasonically dispersed in an aqueous solution of N-methylpyrrolidone to obtain a suspension.

[0008] The suspension was transferred to a supercritical reactor, which was heated to 80-200°C. CO2 was then introduced into the reactor to a pressure of 8-20 MPa, and the mixture was magnetically stirred for 2-8 hours.

[0009] After naturally cooling to room temperature, CO2 was slowly released to relieve pressure. The supercritical fluid suspension was then separated by centrifugation to obtain CO2. 60 Polymer dispersion;

[0010] C 60 The polymer dispersion was placed in a dialysis bag with a molecular weight cutoff of 100 Da and dialyzed for 12-24 hours. The resulting dialysate was then subjected to a rotary evaporator to remove residual solvent and freeze-dried to obtain C. 60 Polymer powder sample.

[0011] In some embodiments, the volume ratio of N-methylpyrrolidone to water in the aqueous solution of N-methylpyrrolidone is 1:10 to 9:10.

[0012] In some embodiments, the aqueous solution of N-methylpyrrolidone further includes a co-solvent that is well compatible with CO2, the co-solvent being selected from one or more of methanol, ethanol, acetone or tetrahydrofuran.

[0013] In some embodiments, the volume ratio of the N-methylpyrrolidone, water, and co-solvent is 5:5:2.

[0014] In some embodiments, the suspension contains C 60 The volume ratio of N-methylpyrrolidone to aqueous solution is 0.1-10 mg / mL.

[0015] In some implementations, the C 60 The polymer has a minimum size of 1.5 nm and a maximum size of 200 nm. 60 The photoluminescence spectrum of the polymer has an excitation peak at 340-500 nm, a blue emission peak at 420-460 nm, and a green emission peak at 496-550 nm.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] This invention utilizes C 60 The strong interaction between CO2 and CO2 molecules provides a simple supercritical CO2 technique for the controllable induction of C under mild conditions. 60 Molecular polymerization, reducing C 60 Molecular symmetry significantly enhances the purity of fullerene C 60 Its fluorescence performance is excellent, with an absolute fluorescence quantum yield of over 9%.

[0018] The fullerene C prepared by this invention 60 The polymer has uniform size and a wide adjustable range, from a minimum of 1.4 nm to a maximum of 200 nm.

[0019] This technique produces fullerene C with controllable size and strong steady-state fluorescence. 60 Polymers will further drive the development of fullerene C 60 Applications in the fields of biomedicine and materials science. Attached Figure Description

[0020] Figure 1 This is the original C of the present invention. 60 XRD patterns of the target products obtained in Examples 1 and 4;

[0021] Figure 2 These are TEM comparison images of the target products obtained in Examples 1-3 of this invention;

[0022] Figure 3 This is a comparison chart of the target product AFM obtained in Examples 1-3 of the present invention;

[0023] Figure 4 These are the TEM and AFM images of the target product obtained in Example 4 of the present invention;

[0024] Figure 5 The PL (Plastic Processing) spectra of the target products obtained in Examples 1-4 of this invention;

[0025] Figure 6 This is the absolute fluorescence quantum yield spectrum of the target product obtained in Example 3 of the present invention.

[0026] Figure 7 This is the PL spectrum of the product obtained in Comparative Example 1 of the present invention; Detailed Implementation

[0027] The present invention will be further described below with reference to embodiments. The following embodiments are only used to illustrate the performance of the present invention more clearly, and should not be limited to the embodiments described below.

[0028] Example 1: Preparation of fullerene C at supercritical temperature of 180℃, 16MPa, and 4h 60 polymer

[0029] 10mg of C 60 The solution was added to a mixture of N-methylpyrrolidone (10 ml), ethanol (4 ml), and deionized water (10 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. Carbon dioxide was injected into the reactor to achieve a supercritical state at 180 °C and 16 MPa, and the mixture was magnetically stirred for 4 hours. After natural cooling to room temperature, the carbon dioxide was released to depressurize the supercritical suspension. The supernatant was obtained by centrifugation and purified in a dialysis bag with a molecular weight retention of 100 Da for 18 hours. The resulting dialysis solution was then subjected to rotary evaporation to remove residual solvent and lyophilized to obtain fullerene C. 60Polymer powder sample.

[0030] like Figure 1 As shown, relative to the original C 60 Sample, C of Example 1 60 The polymer diffraction peaks broadened, and a distinct new peak was formed between 25° and 35°, indicating that C 60 New covalent bonds are formed between molecules.

[0031] Example 2: Preparation of fullerene C at supercritical temperature of 180℃, 12MPa, and 4h 60 polymer

[0032] 10mg of C 60 The solution was added to a mixture of N-methylpyrrolidone (8 ml), ethanol (2 ml), and deionized water (10 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. Carbon dioxide was injected into the reactor to achieve a supercritical state at 180°C and 20 MPa, and the mixture was magnetically stirred for 4 hours. After natural cooling to room temperature, the carbon dioxide was released to depressurize the supercritical suspension. The supernatant was obtained by centrifugation and purified in a dialysis bag with a molecular weight retention of 100 Da for 12 hours. The resulting dialysis solution was then subjected to rotary evaporation to remove residual solvent and lyophilized to obtain fullerene C. 60 Polymer powder sample.

[0033] Example 3: Preparation of fullerene C at supercritical temperature of 180℃, 20MPa, and 4h 60 polymer

[0034] 10mg of C 60 The solution was added to a mixture of N-methylpyrrolidone (5 ml), ethanol (2 ml), and deionized water (6 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. Carbon dioxide was injected into the reactor to achieve a supercritical state at 180°C and 20 MPa, and the mixture was magnetically stirred for 4 hours. After natural cooling to room temperature, the carbon dioxide was released to depressurize the reactor. The supercritical suspension was then separated by centrifugation to obtain the supernatant. Figure 2 and 3 As shown, the target samples obtained in Examples 1-3, with the increase of reaction pressure, C 60 The lateral dimensions of the polymer increased from 1.4 nm to 40 nm, while the thickness ranged from 0.4 to 1.5 nm. For example... Figure 5 As shown, in Example 1, when the supercritical pressure is 16 MPa, C 60 The polymer exhibits the best fluorescence properties. For example... Figure 6 As shown, the absolute fluorescence quantum yield of the sample obtained in Example 3 was 9.85%.

[0035] Example 4: Preparation of two-dimensional fullerene C at supercritical temperature of 180℃, 20MPa, and 6h 60 polymer

[0036] 10mg of C 60 The solution was added to a mixture of N-methylpyrrolidone (10 ml), ethanol (4 ml), and deionized water (10 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. Carbon dioxide was injected into the reactor to achieve a supercritical state at 180 °C and 20 MPa, and the mixture was magnetically stirred for 6 hours. After natural cooling to room temperature, the carbon dioxide was released to depressurize the supercritical suspension. The supernatant was obtained by centrifugation and purified in a dialysis bag with a molecular weight retention of 100 Da for 12 hours. The resulting dialysis solution was then subjected to rotary evaporation to remove residual solvent and lyophilized to obtain fullerene C. 60 Polymer powder sample. For example... Figure 1 As shown, in Comparative Example 2, most of the diffraction peaks disappeared, and a new diffraction peak appeared at 43.5°. Figure 4 As shown, the obtained sample exhibits a monolayer of C with a lateral dimension of 100-200 nm and a thickness of 0.7 nm. 60 Two-dimensional polymer.

[0037] Example 5: Preparation of fullerene C at supercritical temperature of 100℃, 20MPa, and 6h 60 polymer

[0038] 60mg of C 60 The solution was added to a mixture of N-methylpyrrolidone (10 ml), ethanol (4 ml), and deionized water (10 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. Carbon dioxide was injected into the reactor to achieve a supercritical state at 180 °C and 20 MPa, and the mixture was magnetically stirred for 6 hours. After natural cooling to room temperature, the carbon dioxide was released to depressurize the supercritical suspension. The supernatant was obtained by centrifugation and purified in a dialysis bag with a molecular weight retention of 100 Da for 24 hours. The resulting dialysis solution was then subjected to rotary evaporation to remove residual solvent and lyophilized to obtain fullerene C. 60 Polymer powder sample.

[0039] Example 6: Preparation of fullerene C at supercritical temperature of 160℃, 20MPa, and 6h 60 polymer

[0040] 30mg of C 60The solution was added to a mixture of N-methylpyrrolidone (10 ml), ethanol (4 ml), and deionized water (10 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. Carbon dioxide was injected into the reactor to achieve a supercritical state at 160 °C and 16 MPa, and the mixture was magnetically stirred for 6 hours. After natural cooling to room temperature, the carbon dioxide was released to depressurize the supercritical suspension. The supernatant was obtained by centrifugation and purified in a dialysis bag with a molecular weight retention of 100 Da for 16 hours. The obtained dialysis solution was then subjected to rotary evaporation to remove residual solvent and lyophilized to obtain fullerene C. 60 Polymer powder sample.

[0041] Comparative Example 1: Fullerene product obtained at 180℃ for 4 hours under non-supercritical conditions

[0042] 20mg of C 60 The mixture was added to a solution of N-methylpyrrolidone (10 ml), ethanol (4 ml), and deionized water (10 ml), and ultrasonically dispersed to obtain a dispersion. The dispersion was then transferred to a supercritical reactor. The temperature was set to 180°C without CO2 gas filling, and the mixture was magnetically stirred for 4 hours. After natural cooling to room temperature, the precipitate was separated by centrifugation, washed, and dried to obtain the product. Figure 7 As shown, C obtained under non-supercritical conditions 60 The product exhibits extremely weak fluorescence signals within the relevant wavelength range.

[0043] In summary: This invention utilizes C 60 The strong interaction between the carbon and CO2 molecules provides a simple and controllable method for inducing C2O2. 60 Supercritical CO2 technology for molecular polymerization, polymerization leads to C 60 The symmetry of the molecule is reduced, which in turn significantly enhances the purity of fullerene C. 60 The fluorescence properties of fullerene C2O2 can be achieved by simply modulating external thermodynamic parameters (pressure, temperature) and reaction time. 60 Controlled polymerization of molecules. Preparation of the obtained fullerene C 60 The polymers exhibit uniform size and a wide adjustable range, from a minimum of 1.4 nm to a maximum of 200 nm. Notably, this technology can achieve single-layer two-dimensional C 60 Controllable preparation of polymers. This technique produces fullerene C2 with controllable size and strong steady-state fluorescence. 60 Polymers will further drive the development of fullerene C 60 Applications in the fields of biomedicine and materials science.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A high-fluorescence quantum yield fullerene C 60 A method for preparing a polymer, characterized in that, Includes the following steps: C 60 The mixture was ultrasonically dispersed in an aqueous solution of N-methylpyrrolidone to obtain a suspension. The suspension was transferred to a supercritical reactor, which was heated to 80-200°C. CO2 was then introduced into the reactor to a pressure of 8-20 MPa, and the mixture was magnetically stirred for 2-8 hours. After naturally cooling to room temperature, CO2 was slowly released to relieve pressure. The supercritical fluid suspension was then separated by centrifugation to obtain CO2. 60 Polymer dispersion; C 60 The polymer dispersion was placed in a dialysis bag with a molecular weight cutoff of 100 Da and dialyzed for 12-24 hours. The resulting dialysate was then subjected to a rotary evaporator to remove residual solvent and freeze-dried to obtain C. 60 Polymer powder sample.

2. The high fluorescence quantum yield fullerene C according to claim 1 60 A method for preparing a polymer, characterized in that, The volume ratio of N-methylpyrrolidone to water in the aqueous solution of N-methylpyrrolidone is 1:10 to 9:

10.

3. A high fluorescence quantum yield fullerene C according to claim 2 60 A method for preparing a polymer, characterized in that, The aqueous solution of N-methylpyrrolidone also includes a co-solvent that is well compatible with CO2, and the co-solvent is selected from one or more of methanol, ethanol, acetone or tetrahydrofuran.

4. A high fluorescence quantum yield fullerene C according to claim 3 60 A method for preparing a polymer, characterized in that, The volume ratio of N-methylpyrrolidone, water, and co-solvent is 5:5:

2.

5. A high fluorescence quantum yield fullerene C according to claim 1 60 A method for preparing a polymer, characterized in that, C in the suspension 60 The volume ratio of N-methylpyrrolidone to aqueous solution is 0.1-10 mg / mL.

6. A high fluorescence quantum yield fullerene C according to claim 1 60 A method for preparing a polymer, characterized in that, The C 60 The polymer has a minimum size of 1.5 nm and a maximum size of 200 nm. 60 The photoluminescence spectrum of the polymer has an excitation peak at 340-500 nm, a blue emission peak at 420-460 nm, and a green emission peak at 496-550 nm.

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