Janus particles based on GMA monomer emulsion polymerization and preparation method and application thereof

Abstract

The application provides a Janus particle based on GMA monomer emulsion polymerization and a preparation method and application thereof, and belongs to the technical field of functional materials; the application first synthesizes functional composite particles with fine controllable morphology and structure based on GMA monomer in one step, and then prepares amphiphilic PFC-PGMA-NH2 Janus particles based on the functional composite particles; the particles prepared by the method have a topological structure that can be accurately controlled, and the method has the advantages of simple process, low cost and environmental friendliness; the PFC-PGMA-NH2 Janus particles are expected to be used for protein immobilization and interfacial biological catalysis, and have good practicability.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically relating to Janus particles based on GMA monomer emulsion polymerization, their preparation method, and applications. Background Technology

[0002] In recent years, novel Janus materials have attracted much attention due to their unique properties. In terms of morphology and structure, Janus materials exhibit unique steric hindrance effects due to their asymmetry, which can be used to study self-assembly behavior at interfaces. In terms of composition and properties, Janus materials can simultaneously exhibit dual or even opposite properties, such as hydrophobicity and hydrophilicity, negative and positive charge, nonmagnetic and magnetic properties, and polarity and nonpolarity, thus possessing multiple functionalities and adaptability to complex and varied application environments. Due to the unique surface chemical composition and geometry of Janus materials, coupled with their anisotropic properties and orientations, they are widely used in analytical chemistry, medical immunology, bioengineering, information technology, microelectronics, and other fields.

[0003] Currently, the main methods for preparing Janus particles include interface protection, emulsion polymerization, microfluidics, self-assembly, phase separation, and others. Among these, emulsion polymerization is one of the more commonly used synthesis methods. Emulsion polymerization involves the polymerization of different monomers in two phases under the action of surfactants as emulsifiers and combined with mechanical stirring. In emulsion polymerization, the two different polymers can first undergo phase separation through simple solvent evaporation, thus obtaining Janus particles. However, this method produces microspheres with low yields, and the solvents used in the preparation process are highly toxic and easily pollute the environment. In addition, the incompatibility between polymers in emulsion polymerization can produce asymmetric particles. Seed emulsion polymerization is also a type of emulsion polymerization, where the reaction site is generally inside the seed. By controlling the phase separation of the cross-linked network structure within the swollen microspheres, microspheres with different structures can be prepared. Although this method for Janus particles is highly efficient, the operation steps are relatively cumbersome, and the morphology is difficult to control.

[0004] With the development of emulsion preparation technology, emulsion droplet templates have provided various possibilities for the preparation of Janus particles. In commonly used O / W emulsion systems, when suitable monomers are selected as the internal phases within the emulsion droplets, diverse particles can be obtained by adjusting the mass ratio of monomers to surfactants. Initially, the monomers selected were two non-polymerizable monomers. With continuous development, there is a growing tendency to select polymerizable monomers to prepare particles from emulsion droplets. In addition, functional monomers are also added to prepare multifunctional particles. Although these methods can achieve the preparation of functional particles through emulsions, they involve multiple synthetic steps. Therefore, there is a need to develop a simple, one-step method to achieve functional composite particles and Janus particles. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides Janus particles based on GMA monomer emulsion polymerization, their preparation method, and applications. The invention first synthesizes functional composite particles with finely controllable morphology and structure in a one-step process using glycidyl methacrylate (GMA) monomer. Then, amphiphilic PFC-PGMA-NH2 Janus particles are prepared based on these functional composite particles. The particle topology prepared by this method can be precisely controlled, and the process is simple, low-cost, and environmentally friendly. The PFC-PGMA-NH2 Janus particles show promise for protein immobilization and interfacial biocatalysis, demonstrating excellent practicality.

[0006] To achieve the above-mentioned technical objectives, the present invention employs the following technical means:

[0007] This invention first prepares a PFC-PGMA composite particle, which is spherical with a distinct phase boundary on the outer side. One side contains carbon-fluorine bonds, and the other side contains epoxy groups. The PFC-PGMA composite particle is obtained by glycidyl methacrylate-perfluorodecyl acrylate composite emulsion polymerization.

[0008] The preparation of the PFC-PGMA composite particles includes the following steps:

[0009] (1) The glycidyl methacrylate solution and the 1H,1H,2H,2H-perfluorodecyl acrylate solution were mixed uniformly to obtain the dispersed phase of the system;

[0010] SDS and Zonyl FS-300 were dissolved in deionized water and stirred until homogeneous to obtain a continuous phase of the system.

[0011] The dispersed phase and the continuous phase are stirred and mixed evenly to obtain a composite emulsion;

[0012] (2) The composite emulsion was added to the photochemical reactor and the reaction was cured by ultraviolet light. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain PFC-PGMA composite particles.

[0013] Preferably, in step (1), the volume ratio of glycidyl methacrylate and 1H,1H,2H,2H-perfluorodecyl acrylate is 1:1 to 9; and the ratio of SDS to Zonyl FS-300 is 0.001 to 0.07 wt%: 0.001 to 0.03 wt%.

[0014] Preferably, in step (2), the volume ratio of the dispersed phase to the continuous phase is 100:1000μL; and the UV curing reaction time is 5 to 30 min.

[0015] The present invention also provides PFC-PGMA-NH2 Janus particles prepared based on PFC-PGMA composite particles. The PFC-PGMA-NH2 Janus particles are spherical with obvious phase boundaries on the outer side of the spheres. One side contains carbon-fluorine bonds, and the other side is rich in amino groups.

[0016] Preferably, the preparation method of the PFC-PGMA-NH2 Janus particles includes:

[0017] PFC-PGMA composite particles were dispersed in NH3·H2O solution, ultrasonically dispersed, and then reacted in an oil bath. After the reaction was completed, the particles were centrifuged, washed, and dried to obtain PFC-PGMA-NH2 Janus particles.

[0018] Preferably, the ratio of the PFC-PGMA composite particles to the NH3·H2O solution is 100-500 mg: 5-20 mL; and the mass fraction of the NH3·H2O solution is 25-28 wt%.

[0019] The heating temperature for the oil bath reaction is 50–80°C; the heating time is 1–6 hours.

[0020] The present invention also provides the application of PFC-PGMA-NH2 Janus particles in oil-water emulsification; specifically, the ratio of PFC-PGMA-NH2 Janus particles, oil and water is 1-10 mg: 1 mL: 2-9 mL.

[0021] The present invention also provides a PFC-PGMA-NH2@Au Janus catalyst, wherein the catalyst is spherical with a distinct phase boundary on the outer side of the sphere, one side contains carbon-fluorine bonds and the other side contains gold nanoparticles.

[0022] Preferably, the method for preparing the above catalyst includes:

[0023] (1) Disperse PFC-PGMA-NH2 Janus particles in ethanol by ultrasonication, then add HAuCl4 solution, mix well and centrifuge to collect the precipitate;

[0024] (2) The precipitate was dispersed in ethanol and NaBH4 ice water solution was added to obtain a mixture. The mixture was reacted under shaking conditions. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the PFC-PGMA-NH2@Au Janus catalyst.

[0025] Preferably, in step (1), the ratio of the amount of PFC-PGMA-NH2 Janus particles, ethanol, and HAuCl4 solution used is 90-100 mg: 1-20 mL: 1-20 mL; and the concentration of the HAuCl4 solution is 0.05-0.15 mol / L.

[0026] In step (2), the ratio of PFC-PGMA-NH2 Janus particles to NaBH4 ice-water solution is 90-110 mg: 0.5-2 mL; the concentration of NaBH4 solution is 0.05-0.15 mol / L.

[0027] The reaction time is 1 to 12 hours.

[0028] This invention also provides the application of the PFC-PGMA-NH2@Au Janus catalyst in the catalytic reduction of nitro compounds.

[0029] Preferably, the nitro compound includes 4-nitrophenol (4-NP) or 4-nitroanisole.

[0030] Preferably, when the nitro compound is 4-nitrophenol (4-NP), the catalytic reaction includes:

[0031] The PFC-PGMA-NH2@Au Janus catalyst was added to a solution of 4-nitrophenol and ultrasonically dispersed until homogeneous. Then, NaBH4 solution was added to initiate the reaction. After the reaction was complete, the PFC-PGMA-NH2@Au Janus catalyst was washed with ethanol and deionized water, dried, and recycled.

[0032] The ratio of the PFC-PGMA-NH2@Au Janus catalyst, 4-nitrophenol, and NaBH4 ice-water solution is 1-10 mg: 2-8 mL: 0.5-4 mL; the concentration of the 4-nitrophenol (4-NP) solution is 0.001-1 mmol / L; and the concentration of the NaBH4 solution is 0.01-0.1 mol / L.

[0033] Preferably, when the nitro compound is 4-nitrobenzyl ether, the catalytic reaction includes:

[0034] The PFC-PGMA-NH2@Au Janus catalyst was added to a toluene solution of 4-nitrobenzene ether and ultrasonically dispersed until homogeneous. Then, NaBH4 solution was added to initiate the reaction. After the reaction was complete, the PFC-PGMA-NH2@Au Janus catalyst was washed with ethanol and deionized water, dried, and recycled.

[0035] The ratio of the PFC-PGMA-NH2@Au Janus catalyst, 4-nitroanisole, and NaBH4 ice-water solution is 1–10 mg: 2–8 mL: 0.5–4 mL; the concentration of the 4-nitroanisole solution is 0.001–1 mmol / L; and the concentration of the NaBH4 solution is 0.01–0.1 mol / L.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) The present invention uses glycidyl methacrylate solution as functional group reactant and 1H,1H,2H,2H-perfluorodecyl acrylate as reactant, which are easy to polymerize and have good activity for UV curing.

[0038] (2) By simply adjusting the volume ratio of the oil phase in the dispersed phase and the volume ratio of the surfactant in the continuous phase, functional composite emulsions with different morphologies can be obtained in one step. Using this emulsion as a template, the spherical morphology of Janus particles can be controlled, i.e., the different positions of the phase boundary on the particle surface, so as to adjust the hydrophilic / hydrophobic properties of Janus particles.

[0039] (3) The preparation method of Janus particles adopts emulsion polymerization and photopolymerization techniques, which are fast, convenient and controllable, and do not require organic solvents. The production cost is low, and it has certain industrial application value.

[0040] (4) The synthesized functional Janus particles exhibit good emulsifying properties and excellent catalytic performance in the reaction of nitro compounds. After 5 cycles, the catalytic efficiency remains above 88%. It is expected to be applied in fields such as the immobilization of biological proteins and interfacial catalysis. Attached Figure Description

[0041] Figure 1 This is a phase diagram of stable composite emulsions with different surfactant formulations when the monomer ratio of glycidyl methacrylate and perfluorodecyl acrylate is 1:1.

[0042] Figure 2 This is a phase diagram of a stable composite emulsion with different surfactant formulations when the monomer ratio of glycidyl methacrylate and perfluorodecyl acrylate is 7:3. In the figure, (a1) represents SDS:Zonyl FS-300 = 0.07:0.001wt%; (b1) represents SDS:Zonyl FS-300 = 0.01:0.001wt%; and (c1) represents SDS:Zonyl FS-300 = 0.01:0.01wt%.

[0043] Figure 3This is a phase diagram of a stable composite emulsion with different surfactants when the monomer ratio of glycidyl methacrylate and perfluorodecyl acrylate is 3:7. In the figure, (a1) is SDS:Zonyl FS-300 = 0.07:0.001wt%; (b1) is SDS:Zonyl FS-300 = 0.01:0.001wt%; (c1) is SDS:Zonyl FS-300 = 0.01:0.01wt%.

[0044] Figure 4 This is a flowchart of the preparation of Janus particles based on GMA monomer emulsion polymerization.

[0045] Figure 5 The images show the FT-IR spectra of PFC-PGMA particles and PFC-PGMA-NH2 Janus particles (a), the Zeta potential of PFC-PGMA-NH2 Janus particles (b), and the inverted fluorescence microscope image of PFC-PGMA-NH2 Janus particles (c). C1 and C2 are the bright and dark fields of the inverted fluorescence microscope image of PFC-PGMA-NH2 Janus particles (SDS:Zonyl FS-300 = 0.03:0.001wt%), respectively; C3 and C4 are the bright and dark fields of the inverted fluorescence microscope image of PFC-PGMA-NH2 Janus particles (SDS:Zonyl FS-300 = 0.01:0.001wt%), respectively.

[0046] Figure 6 The images show SEM images of composite particles (PFC-PGMA) prepared under different formulations of surfactants; in the images, a1 to a4 are SEM images of composite particles (PFC-PGMA) prepared under different proportions of SDS; b1 to b4 are SEM images of composite particles (PFC-PGMA) prepared under different proportions of Zonyl FS-300.

[0047] Figure 7 SEM images (a) and EDX images (b-e) of PFC-PGMA-NH2 Janus particles are shown; where b represents C, c represents O, d represents F, and e represents all elements.

[0048] Figure 8 SEM images of PFC-PGMA particles (a) and PFC-PGMA-NH2 Janus particles (b).

[0049] Figure 9 SEM image (a) and XRD image (b) of PFC-PGMA-NH2@Au Janus particles.

[0050] Figure 10Emulsion diagrams of PFC-PGMA-NH2 Janus particles (a) and PFC-PGMA-NH2@BSA (b).

[0051] Figure 11 Figure 1 shows the catalytic reduction of 4-nitrophenol (4-NP) using PFC-PGMA-NH2@Au Janus catalyst. In the figure, a is a model diagram of the catalytic reduction of 4-nitrophenol using PFC-PGMA-NH2@Au Janus catalyst; b is the UV spectrum of 4-nitrophenol and 4-aminophenol; c is the conversion rate of 4-nitrophenol catalyzed by PFC-PGMA-NH2@Au Janus catalyst at different reaction times; d is the C / C0 ratio of 4-nitrophenol as a function of reaction time under PFC-PGMA-NH2@Au Janus catalyst catalysis; e is the UV spectrum of 4-nitrophenol catalyzed by PFC-PGMA-NH2@Au Janus catalyst in cyclic catalysis; and f is the conversion rate histogram of 4-nitrophenol catalyzed by PFC-PGMA-NH2@Au Janus catalyst in cyclic catalysis.

[0052] Figure 12 Figure 1 shows the catalytic reduction of 4-nitrobenzene ether by PFC-PGMA-NH2@Au Janus catalyst at the oil / water emulsion interface. In the figure, a is the concentration-absorbance standard curve of 4-nitrobenzene ether; b is the UV spectrum of 4-nitrobenzene ether reduction catalyzed by PFC-PGMA-NH2@Au Janus catalyst at different reaction times; c is the conversion rate of 4-nitrobenzene ether catalyzed by PFC-PGMA-NH2@Au Janus catalyst at different reaction times; d is the C / C0 ratio of 4-nitrobenzene ether as a function of reaction time under the catalysis of PFC-PGMA-NH2@Au Janus catalyst; e is the UV spectrum of 4-nitrobenzene ether catalyzed by PFC-PGMA-NH2@Au Janus catalyst in a cyclic process; and f is the histogram of the conversion rate of 4-nitrobenzene ether catalyzed by PFC-PGMA-NH2@Au Janus catalyst in a cyclic process.

[0053] Figure 13 The figure shows the catalytic reduction of 4-nitrobenzene ether by PFC-PGMA-NH2@Au Janus catalyst at the oil-water interface; in the figure, a is the conversion rate of 4-nitrobenzene ether by PFC-PGMA-NH2@Au Janus catalyst at different reaction times; b is the C / C0 of 4-nitrobenzene ether as a function of reaction time under the catalysis of PFC-PGMA-NH2@Au Janus catalyst.

[0054] Figure 14Histogram comparing the conversion rates of 4-nitrobenzyl ether catalyzed by PFC-PGMA-NH2@Au Janus catalyst at the same reaction time. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0056] Example 1: Preparation and optimization of conditions for (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion

[0057] Preparation of S1. (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion

[0058] This step prepared a (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion, and the specific preparation method is as follows:

[0059] 50 μL of glycidyl methacrylate solution and 50 μL of perfluorodecyl acrylate solution were mixed thoroughly to obtain the dispersed phase of the system. 0.001 wt% sodium dodecyl sulfonate (SDS) and 0.001 wt% fluorocarbon surfactant (Zonyl FS-300) were mixed thoroughly to obtain the continuous phase of the system. The dispersed and continuous phases were mixed thoroughly to obtain a mixture with a dispersed phase concentration of 0.1 mL / mL. The mixture was emulsified at 25 °C to obtain a (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion system.

[0060] Optimization of preparation conditions for S2 (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion:

[0061] In this step, the preparation conditions were optimized by examining the effects of surfactant (SDS) concentration, surfactant (Zonyl FS-300) concentration, and the volume ratio of glycidyl methacrylate and perfluorodecyl acrylate monomers on the morphology of the composite emulsion. The specific optimization process is shown below.

[0062] (1) Effect of surfactant (SDS) concentration on the morphology of composite emulsion:

[0063] For oil-in-water emulsions, the properties of surfactants drive changes in the interfacial tension between the two phases, thereby controlling the topology of the composite emulsion. Therefore, the concentration of surfactant (SDS) significantly affects the morphology of the composite emulsion. In this step, the concentration of surfactant (Zonyl FS-300) was fixed at 0.001 wt%, and the concentrations of surfactant (SDS) were adjusted to 0.001 wt%, 0.01 wt%, 0.03 wt%, and 0.07 wt% to investigate the effect of surfactant (SDS) concentration on the droplet morphology of the composite emulsion. The results are as follows: Figure 1 As shown.

[0064] Depend on Figure 1 It can be seen that different ratios of the composite surfactant can stabilize the emulsion and produce emulsion droplets with relatively uniform particle size. When the concentration of the surfactant (Zonyl FS-300) is fixed at 0.001 wt%, increasing the concentration of the surfactant (SDS) will cause changes in the interface between the two phases, promoting the formation of a composite emulsion from Janus type to F / H / W type. Figure 1 (a1)-(a4)).

[0065] (2) Effect of surfactant (Zonyl FS-300) concentration on the morphology of composite emulsion:

[0066] The type and concentration of surfactants also have a significant impact on the morphology of composite emulsions. In this step, the concentration of surfactant (SDS) was fixed at 0.001 wt%, and the concentrations of surfactant (Zonyl FS-300) were adjusted to 0.001 wt%, 0.005 wt%, 0.01 wt%, and 0.02 wt% to investigate the effect of surfactant (Zonyl FS-300) concentration on the droplet morphology of the composite emulsion. The results are as follows. Figure 1 As shown.

[0067] Depend on Figure 1 It can be seen that when the concentration of surfactant (SDS) is fixed at 0.001 wt%, the physicochemical properties inside the emulsion droplets change with the increase of surfactant (Zonyl FS-300), resulting in a continuous change in the morphology of the composite emulsion, transforming from Janus type to H / F / W type biemulsion. Figure 1 (a1)-(d1)).

[0068] (3) Effect of the volume ratio concentration of glycidyl methacrylate and perfluorodecyl acrylate monomers on the morphology of the composite emulsion:

[0069] This step investigated the effect of adjusting the monomer volume ratios of glycidyl methacrylate and perfluorodecyl acrylate to 1:1, 7:3, and 3:7 on the morphology of the composite emulsion. The results are as follows: Figure 1-3 As shown.

[0070] Combination Figure 1-3 It can be seen that equal volumes of perfluorodecyl acrylate (F) and glycidyl methacrylate (H) as the internal oil phase exhibit perfect compatibility at room temperature, and a (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion system is constructed with surfactants (SDS) and (Zonyl FS-300) in combination.

[0071] from Figure 2 The data shows that when the volume ratio of glycidyl methacrylate to perfluorodecyl acrylate monomers is 7:3, the morphology of the (glycidyl methacrylate-perfluorodecyl acrylate) composite emulsion changes accordingly with the concentration of the compound surfactant solution. When the concentration of surfactant (Zonyl FS-300) is fixed at 0.001 wt%, and the concentration of surfactant (SDS) increases from 0.01 wt% to 0.07 wt%, the droplet morphology of the composite emulsion changes from Janus type to F / H / W type. Figure 2 (b1)-(a1)). When the concentration of surfactant (SDS) is fixed at 0.01 wt%, and the concentration of surfactant (Zonyl FS-300) increases from 0.001 wt% to 0.01 wt%, the droplets of the composite emulsion are Janus-type emulsion droplets with different morphologies. Figure 2 (b1)-(c1)). The interfacial tension between the two phases changes with the concentration of the surfactant, resulting in different emulsion morphologies.

[0072] from Figure 3 The data shows that when the volume ratio of glycidyl methacrylate to perfluorodecyl acrylate monomers is 3:7, and when the concentration of surfactant (Zonyl FS-300) is fixed at 0.001 wt%, increasing the concentration of surfactant (SDS) from 0.01 wt% to 0.07 wt% will change the droplet morphology of the composite emulsion from Janus type to H / W type. Figure 3(b1)-(a1)), this is because at this concentration, the surfactant (SDS) molecules and surfactant (Zonyl FS-300) molecules are fully packed at the HW interface, making it difficult to further change the morphology of the emulsion droplets. When the concentration of surfactant (SDS) is fixed at 0.01 wt%, when the concentration of surfactant (Zonyl FS-300) increases from 0.001 wt% to 0.01 wt%, the droplet morphology of the composite emulsion changes from Janus type to H / F / W type emulsion (…). Figure 3 (b1)-(c1)).

[0073] In summary, the optimized preparation conditions for the composite emulsion are as follows: the volume ratio of glycidyl methacrylate to perfluorodecyl acrylate monomers is 1:1; the concentration of surfactant (SDS) is 0.001 wt%; and the concentration of surfactant (Zonyl FS-300) is 0.001 wt%.

[0074] Example 2: Preparation of Janus particles:

[0075] The process for preparing Janus particles based on GMA monomer emulsion polymerization is as follows: Figure 4 As shown, glycidyl methacrylate (GMA) was selected as the hydrocarbon phase, and 1H,1H,2H,2H-perfluorodecyl acrylate (FC) was selected as the fluorocarbon phase. A composite surfactant aqueous solution was prepared using sodium dodecyl sulfonate (SDS) and a fluorocarbon surfactant (Zonyl FS-300). The oil and water phases were emulsified to prepare a composite emulsion. The morphology of the composite emulsion was then controlled by adjusting the ratio of different surfactants. Ultraviolet light was used to initiate the polymerization of the two monomers, and the composite emulsion was cured to prepare PFC-PGMA composite particles. Then, ammonia was used to modify the glycidyl methacrylate side, introducing amino groups onto the surface of the microspheres to obtain PFC-PGMA-NH2Janus particles. The specific steps are shown below:

[0076] (1) Preparation of PFC-PGMA composite particles:

[0077] Five mL of the composite emulsion prepared under the optimal conditions in Example 1 was placed in a five mL glass reactor, and then placed together in a photochemical reactor equipped with a 300 W UV lamp. The reaction was carried out for 30 min. The sample was then removed, centrifuged, and the pale yellow precipitate was collected. The precipitate was washed several times with methanol, acetone, and deionized water in sequence. After drying to constant weight, PFC-PGMA composite particles were obtained.

[0078] (2) Preparation of PFC-PGMA-NH2 Janus particles:

[0079] The PFC-PGMA composite particles were placed in a 50 mL flask, and 10 mL of 28 wt% NH3·H2O solution was added. The mixture was then reacted at 60 °C for 6 h. After the reaction was completed, the mixture was centrifuged, washed with deionized water until the solution was neutral, and dried to constant weight to obtain PFC-PGMA-NH2 Janus particles.

[0080] (3) Preparation of PFC-PGMA-NH2@Au Janus catalyst:

[0081] 100 mg of PFC-PGMA-NH2 Janus particles were ultrasonically dispersed in 20 mL of ethanol, and then 500 μL (0.1 mol / L) of HAuCl4 solution was added. The mixture was shaken on a shaker at room temperature for 12 h. After the reaction was completed, the excess HAuCl4 solution was removed by centrifugation to obtain the precipitate.

[0082] The precipitate was redispersed in ethanol, and 2 mL (0.1 mol / L) of NaBH4 ice-water solution was quickly added. The reaction was continued to be shaken for 12 h. After the reaction was completed, the catalyst was centrifuged, washed several times with ethanol, and dried to constant weight to obtain the PFC-PGMA-NH2@AuJanus catalyst.

[0083] Figure 5 These are the FT-IR spectra of PFC-PGMA particles and PFC-PGMA-NH2 Janus particles. Figure 5 As shown in (a), 910cm -1 and 851cm -1 It is a characteristic peak of the epoxy group, 1728 cm⁻¹ -1 It is a characteristic peak of C=O in the ester group, 2800-3000 cm⁻¹ -1 These are characteristic absorption peaks of the methyl and methylene groups in the carbon chain. Infrared spectroscopy confirmed that a polymerization reaction occurred between the perfluorodecyl acrylate monomer and the glycidyl methacrylate monomer, thereby introducing epoxy groups. The results indicate the successful preparation of the composite microspheres. Modification of the glycidyl methacrylate side of the composite particles using ammonia water was observed in the infrared spectrum. Figure 5 (a) Fingerprint area 910cm -1 and 851cm -1 The characteristic peaks of the epoxy groups have basically disappeared, and the 3470 cm⁻¹ peak has also disappeared. -1 The appearance of the amino characteristic peak proves that the poly(glycidyl methacrylate) side of the composite microspheres has been successfully modified, indicating that the PFC-PGMA-NH2 Janus particles have been successfully prepared.

[0084] like Figure 5As shown in (b), when the solution pH is 3, the Zeta potential of the PFC-PGMA-NH2 Janus particles is +43 mV, indicating a stronger electrostatic repulsion between the Janus particles (while the interaction between amino groups is a weaker hydrophobic repulsion). As the solution pH increases, the Zeta potential of the Janus particles changes from +43 mV to -17.89 mV, which is attributed to the successful modification of the composite particles. By adjusting the solution pH, the surface potential of the Janus particles can be altered, thus making it easier to control the hydrophilic-hydrophobic balance at the interface, allowing the oil-water emulsion system stabilized by the Janus particles to maintain good stability.

[0085] Figure 5 (c) is an inverted fluorescence microscope image of PFC-PGMA-NH2 Janus particles prepared under different surfactant ratios. To verify the successful preparation of PFC-PGMA-NH2 Janus particles, they were further characterized using an inverted fluorescence microscope. The PFC-PGMA-NH2 Janus particles prepared in this example have a carbon-fluorine phase containing carbon-fluorine bonds on one side, while the other side is rich in amino groups. These were labeled with fluorescein isothiocyanate (FITC). Only the side with amino groups reacted with FITC and emitted fluorescence. The characterization results are shown below. Figure 5 As shown in (c), the PFC-PGMA-NH2Janus particles exhibit green fluorescence on one side, with stronger fluorescence inside and weaker, irregular fluorescence at the edges. This not only confirms the successful modification of the composite particles (PFC-PGMA) but also demonstrates that the PFC-PGMA-NH2Janus particles prepared in this example possess an asymmetric structure. The weak fluorescence on the perfluoroacrylate side of the PFC-PGMA-NH2Janus particles in the fluorescence microscope image is mainly due to diffuse reflection and scattering caused by the bright light emitted from the fluorescent groups at the edge of the other side of the particles.

[0086] This example demonstrates the preparation of PFC-PGMA composite particles by constructing a composite emulsion and then curing it under ultraviolet light, and the resulting PFC-PGMA composite particles are characterized. Figure 6 These are SEM images of composite particles (PFC-PGMA) prepared under different surfactant formulations. The images show that when the volume ratio of the two monomers is 1:1, Figure 6 (a1-a4) are PFC-PGMA composite microspheres prepared when the concentration of surfactant (ZonylFS-300) is 0.001 wt% and the concentration of surfactant (SDS) is 0.001, 0.01, 0.03, and 0.07 wt%, respectively. Figure 6(b1-b4) are PFC-PGMA microspheres prepared when the concentration of surfactant (SDS) is 0.001 wt% and the concentration of surfactant (Zonyl FS-300) is 0.001 wt%, 0.005 wt%, 0.01 wt%, and 0.02 wt%, respectively. Figure 6 As can be seen, the composite particles retain a spherical morphology with an average size of 14 μm despite adjustments to the surfactant ratio. Therefore, the two-phase interface of the composite particles can be tuned by adjusting the surfactant ratio, enabling the subsequent preparation of PFC-PGMA-NH2 Janus particles with different hydrophilicity and hydrophobicity.

[0087] Figure 7 This is an EDX image of PFC-PGMA-NH2 Janus particles. The particles were observed using a scanning electron microscope. Figure 7 The scanning electron microscope image in (a) shows that the particles are spherical with distinct phase boundaries, indicating that the PFC-PGMA-NH2 Janus particles have an asymmetric structure. Figure 7 (a) Particles were subjected to EDX elemental analysis. It can be clearly seen that the particles contain a large amount of C, O, and F elements, and a large amount of fluorine elements are mainly distributed on one side of the particles, indicating that the two sides of the particles have different chemical compositions, which further proves the successful preparation of PFC-PGMA-NH2 Janus particles.

[0088] Figure 8 These are SEM images of PFC-PGMA composite particles and PFC-PGMA-NH2 Janus particles. (SEM images were obtained using scanning electron microscopy.) Figure 8 The results show that both the PFC-PGMA composite particles and the PFC-PGMA-NH2 Janus particles exhibit a spherical morphology. This indicates that the morphology of the microspheres did not change significantly before and after modification, maintaining their original spherical shape. The size of the PFC-PGMA-NH2 Janus particles is comparable to that of the composite particles, showing virtually no change. This is likely because the size of the functionalized groups is negligible compared to the size of the composite microparticles.

[0089] Figure 9 These are SEM and XRD images of PFC-PGMA-NH2@Au Janus particles. Because the synthesized PFC-PGMA-NH2 Janus particles have an amino group on one side, Au nanoparticles are loaded onto the amino side of the Janus particles through the coordination of -NH2 and chloroauric acid and the reduction effect of NaBH4. Figure 9(a) is a SEM image of the side of the PFC-PGMA-NH2@Au Janus particle surface containing amino groups. It can be seen that the surface of the spherical particles is slightly rough, indicating the loading of gold nanoparticles. From the XRD pattern in 9(b), it can be seen that 2θ=38.20°, 44.40°, 64.60°, 78.00°, and 82.20° are the diffraction characteristic peaks of Au, further demonstrating the successful preparation of the PFC-PGMA-NH2@Au Janus catalyst.

[0090] Example 3: Study on the emulsifying properties of PFC-PGMA-NH2 Janus particles

[0091] The PFC-PGMA-NH2 Janus particles prepared in this invention, due to their unique amphiphilic structure, can be used as solid surfactants to stabilize emulsions formed by oil and aqueous phases. In this embodiment, a toluene-water mixture was selected as a model of an incompatible oil / water system to study the emulsifying properties of the PFC-PGMA-NH2 Janus particles at 25°C. The specific steps were as follows: 10 mg of PFC-PGMA-NH2 Janus particles were added to a glass bottle containing an oil / water mixture (oil / water volume ratio 1:9), and sonicated for 10 min to ensure thorough mixing and emulsification. To facilitate the differentiation between the oil and aqueous phases, a small amount of Sudan IV dye was added to selectively stain the toluene solution.

[0092] Figure 10 These are stable emulsion diagrams of PFC-PGMA-NH2 Janus particles (a) and PFC-PGMA-NH2@BSA (b), as shown. Figure 10 As shown in (a), after ultrasonic treatment, the toluene oil phase and the aqueous phase (V:V / 1:9) in both systems fused to form a milky white emulsion. After standing for 6 hours, the system with added PFC-PGMA-NH2 Janus particles still maintained a good emulsion state; as Figure 10 As shown in (b), PFC-PGMA-NH2 Janus particles immobilized with bovine serum albumin showed better and longer-lasting stabilization of oil / water emulsions. This indicates that PFC-PGMA-NH2 Janus particles can act as both a solid emulsifier and a carrier to improve the stability of biological enzymes.

[0093] Therefore, PFC-PGMA-NH2 Janus particles with reactive functional groups can be covalently coupled with protein and enzyme molecules, and can be applied to many fields such as organic reactions, biocatalysis, drug delivery, and molecular imaging.

[0094] Example 4: Study on the reduction performance of 4-nitrophenol by PFC-PGMA-NH2@Au Janus catalyst in all-aqueous phase

[0095] In this example, the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-NA) was selected as a model reaction to evaluate the catalytic performance of the PFC-PGMA-NH2@Au Janus catalyst. The specific steps are as follows:

[0096] 10 mg of PFC-PGMA-NH2@Au Janus catalyst was weighed and added to 4.5 mL (0.1 mmol / L) of 4-nitrophenol (4-NP) solution for ultrasonic dispersion. Then, 0.5 mL (0.05 mol / L) of NaBH4 solution was rapidly added. Samples were taken at certain time intervals, and the absorbance of 4-NP was obtained by UV-vis measurement, from which the conversion rate of 4-NP was calculated. Finally, the PFC-PGMA-NH2@Au Janus catalyst was recycled to study its cyclic catalytic performance.

[0097] Figure 11 This is a diagram showing the catalytic reduction of 4-nitrophenol (4-NP) using the PFC-PGMA-NH2@Au Janus catalyst. Figure 11 As shown in (b), the absorption peak of 4-nitrophenol solution in the UV-vis spectrum is located at 317 nm. However, after adding NaBH4 solution, 4-nitrophenol forms 4-nitrophenol ions under alkaline conditions, so the maximum absorption of 4-nitrophenol aqueous solution at 317 nm redshifts to 400 nm, and the reaction solution changes from light yellow to dark yellow. Without a catalyst, the UV-vis spectrum of 4-nitrophenol in NaBH4 solution does not fluctuate. However, in the reaction system containing the PFC-PGMA-NH2@Au Janus catalyst, with the addition of NaBH4 solution, by taking samples at intervals during the reaction process for UV-vis spectroscopy testing, it can be observed that the 4-NP UV absorption peak at 400 nm gradually decreases, and a 4-NA UV absorption peak appears near 300 nm. These phenomena indicate that the reduction reaction of 4-NP proceeds in the presence of a catalyst. Figure 11 As shown in (c), the conversion rate of 4-nitrophenol can be calculated based on the concentration-absorbance standard curve of 4-nitrophenol. The conversion rate of 4-NP reaches 97.01% at 120 s, and the reactant 4-NP has essentially reacted completely at 180 s. Furthermore, during the reaction, C... NaBH4 / C p-NP =500, the first-order kinetic constant of the reaction can be calculated using the pseudo-first-order kinetic equation. There is a good linear relationship between ln(C / C0) and the reaction time, and the calculated apparent rate constant (k) is 0.025 min. -1 ( Figure 11 (d)). Finally, the PFC-PGMA-NH2@Au Janus catalyst was recycled multiple times. Figure 11As shown in (e)-(f), the PFC-PGMA-NH2@Au Janus catalyst still exhibits excellent catalytic performance after five cycles of catalytic reduction reaction.

[0098] In summary, the PFC-PGMA-NH2@Au Janus catalyst exhibits excellent catalytic performance in the all-aqueous phase catalysis of 4-nitrophenol, and is easily recovered and recyclable.

[0099] Example 5: Study on the interfacial catalytic reduction performance of 4-nitrobenzene by PFC-PGMA-NH2@Au Janus catalyst

[0100] To further investigate the catalytic performance of the PFC-PGMA-NH2@Au Janus catalyst, this example uses the reduction of 4-nitroanisole to 4-aminoanisole as a model reaction to evaluate the catalytic performance of the PFC-PGMA-NH2@Au Janus catalyst at different reaction interfaces.

[0101] (1) PFC-PGMA-NH2@Au Janus catalyst oil / water emulsion interfacial catalysis of 4-nitrobenzyl ether:

[0102] This step utilizes a PFC-PGMA-NH2@Au Janus catalyst to catalyze the reduction reaction of 4-nitrobenzene ether at the oil / water emulsion interface. The specific process is as follows: 10 mg of the PFC-PGMA-NH2@Au Janus catalyst was weighed and added to 5 mL (0.1 mmol / L) of 4-nitrobenzene ether solution for ultrasonic dispersion. Then, 4 mL (0.05 mol / L) of NaBH4 solution was rapidly added. The mixture was vigorously stirred using a high-speed disperser to form an oil-in-water emulsion. Catalytic reduction was carried out at the oil / water emulsion interface at room temperature. After the reaction, samples were taken at regular intervals and centrifuged to break the emulsion. The upper oil phase was collected, and the absorbance of 4-nitrobenzene ether was measured using UV-vis. The conversion rate was calculated based on the absorbance of 4-nitrobenzene ether. Finally, the PFC-PGMA-NH2@Au Janus catalyst was centrifuged and washed several times with ethanol and deionized water for recycling, and its cyclic catalytic performance was studied.

[0103] Figure 12This is a graph showing the catalytic reduction of 4-nitrobenzene ether at the oil / water emulsion interface using PFC-PGMA-NH2@Au Janus catalyst. PFC-PGMA-NH2@Au Janus can be used not only as a solid emulsifier in oil-water emulsion experiments but also as a catalyst in chemical reactions. First, this example focuses on the catalytic reduction of 4-nitrobenzene ether at the oil / water emulsion interface. The oil phase consists of 4-nitrobenzene ether and toluene solution, while the aqueous phase contains NaBH4 solution. UV-Vis measurements showed that the characteristic UV absorption peak of 4-nitrobenzene ether is located at 304 nm. Therefore, different concentrations of 4-nitrobenzene ether solutions were measured at the 304 nm UV absorption peak, and a concentration-absorbance standard curve for 4-nitrobenzene ether was plotted. Figure 12 (a)). From Figure 12 As shown in (b), under the catalysis of PFC-PGMA-NH2@Au Janus catalyst, the absorption peak of 4-nitrobenzene gradually decreases with increasing reaction time. The conversion rate of 4-nitrobenzene can be determined by establishing a concentration-absorbance standard curve. Figure 12 As shown in (c), using PFC-PGMA-NH2@Au Janus catalyst as the emulsion interface catalyst, the conversion rate of 4-nitrobenzene ether reached 54.88% within 60 min, and the reaction was almost completed within 150 min. Based on the linear relationship between ln(C / C0) and reaction time, the apparent rate constant (k) was calculated to be 0.014 min. -1 ( Figure 12 (d) Similarly, recycling the PFC-PGMA-NH2@Au Janus catalyst, after 5 cycles, did not significantly reduce its catalytic efficiency, which remained above 88%. Figure 12 (e)-(f)). This indicates that the prepared PFC-PGMA-NH2@Au Janus catalyst has good catalytic efficiency and reusability at the oil / water emulsion interface.

[0104] (2) PFC-PGMA-NH2@Au Janus catalyst oil-water two-phase interface catalysis of 4-nitrobenzene:

[0105] This step utilizes a PFC-PGMA-NH2@Au Janus catalyst at the oil / water emulsion interface to catalyze the reduction reaction of 4-nitrobenzene ether. The specific procedure is as follows: 10 mg of the PFC-PGMA-NH2@Au Janus catalyst is weighed and added to 5 mL (0.1 mmol / L) of a 4-nitrobenzene ether solution for ultrasonic dispersion. Then, 4 mL (0.05 mol / L) of a NaBH4 solution is rapidly added. The reduction of 4-nitrobenzene ether occurs at the two-phase interface. Samples are taken intermittently, and the absorbance of the upper oil phase is obtained by UV-vis measurement of 4-nitrobenzene ether. Finally, the catalyst is recovered and its cyclic catalytic performance is studied.

[0106] Figure 13 This is a diagram showing the catalytic reduction of 4-nitrobenzene ether at the oil-water interface using a PFC-PGMA-NH2@Au catalyst. Figure 13 As shown, the PFC-PGMA-NH2@Au Janus catalyst exhibits weak catalytic activity at the oil-water interface. When the PFC-PGMA-NH2@Au Janus catalyst is used at the oil-water interface, the conversion rate of 4-nitrobenzene ether reaches only 2.63% within 60 min, while it reaches 8.74% after 120 min. Figure 13 (a) Based on the linear relationship between ln(C / C0) and reaction time, the apparent rate constant (k) was calculated to be 0.00061 min. -1 ( Figure 13 (b) In the catalytic reduction reaction at the oil-water interface, the PFC-PGMA-NH2@Au Janus catalyst was dispersed at the interface between a toluene solution of 4-nitroanisole and an aqueous solution of NaBH4. Due to the slow mass transfer between the oil-water interface, its catalytic efficiency was low.

[0107] (3) Performance analysis of PFC-PGMA-NH2@Au Janus catalyst in interfacial catalysis:

[0108] This step utilizes the reduction reaction of 4-nitrobenzene ether as a model to study and analyze the catalytic activity of the PFC-PGMA-NH2@AuJanus catalyst at the oil / water emulsion interface and the oil-water two-phase interface. UV-Vis spectroscopy analysis was performed on samples catalyzed at the oil / water emulsion interface and the oil-water two-phase interface to compare the conversion rates at corresponding time points.

[0109] Figure 14 This is a histogram comparing the conversion rates of 4-nitrobenzyl ether catalyzed by PFC-PGMA-NH2@Au Janus catalyst over the same time period. Figure 14Data shows that the PFC-PGMA-NH2@Au Janus catalyst achieved a 90.30% conversion rate of 4-nitrobenzene ether at the oil / water emulsion interface after 150 min of catalytic reaction, which is nearly 10.33 times higher than the efficiency at the oil-water two-phase interface under the same feed amount and reaction time. The results indicate that the catalytic efficiency of the PFC-PGMA-NH2@Au Janus catalyst at the oil / water emulsion interface is significantly better than that at the oil-water two-phase interface. This can be attributed to the unique amphiphilic nature of the PFC-PGMA-NH2@Au Janus catalyst, which plays a good emulsifying role in the oil-water system, effectively transforming the oil-water two-phase interface into an oil / water emulsion interface, greatly increasing the contact area between the reaction systems, and thus significantly improving the catalytic efficiency of the catalyst.

[0110] In summary, the PFC-PGMA-NH2@Au Janus catalyst exhibits catalytic activity at both the oil / water emulsion interface and the oil-water two-phase interface, but its catalytic activity is higher at the oil / water emulsion interface.

[0111] In summary, this invention provides a simple and green synthetic method for preparing PFC-PGMA-NH2 Janus particles. First, the topological structure of the composite emulsion is controlled using a fluorocarbon surfactant (Zonyl FS-300) and anionic surfactant (SDS), thereby synthesizing functional PFC-PGMA composite particles. Then, amphiphilic PFC-PGMA-NH2 Janus particles are prepared by further modification with ammonia. Finally, utilizing the reactivity of amino groups, a PFC-PGMA-NH2@Au Janus catalyst is prepared, exhibiting excellent catalytic performance in the catalytic reduction of nitro compounds.

[0112] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing PFC-PGMA composite particles, characterized in that, include: (1) Glycidyl methacrylate solution and 1H,1H,2H,2H-perfluorodecyl acrylate solution were mixed evenly to obtain the dispersed phase of the system; SDS and Zonyl FS-300 were dissolved in deionized water and stirred evenly to obtain the continuous phase of the system; then the dispersed phase and the continuous phase were stirred evenly to obtain the composite emulsion. (2) The composite emulsion was added to the photochemical reactor and the reaction was cured by ultraviolet light. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain PFC-PGMA composite particles.

2. The method for preparing PFC-PGMA composite particles according to claim 1, characterized in that, In step (1), the volume ratio of glycidyl methacrylate and 1H,1H,2H,2H-perfluorodecyl acrylate is 1:1~9; the ratio of SDS to ZonylFS-300 is 0.001~0.07 wt%:0.001~0.03 wt%.

3. The method for preparing PFC-PGMA composite particles according to claim 1, characterized in that, In step (2), the volume ratio of the dispersed phase to the continuous phase is 100 μL: 1000 μL; The UV curing reaction time is 5~30 min.

4. The PFC-PGMA composite particles prepared by the method according to any one of claims 1 to 3, characterized in that, The PFC-PGMA composite particles are spherical with a distinct phase boundary on the outer side. One side of the phase boundary contains carbon-fluorine bonds, and the other side contains epoxy groups. The PFC-PGMA composite particles are obtained by glycidyl methacrylate-perfluorodecyl acrylate composite emulsion polymerization.

5. A Janus particle based on GMA monomer emulsion polymerization, characterized in that, The Janus particles based on GMA monomer emulsion polymerization are prepared based on the PFC-PGMA composite particles described in claim 4; the Janus particles based on GMA monomer emulsion polymerization are spherical with obvious phase boundaries on the outer side of the sphere, one side contains carbon-fluorine bonds and the other side is rich in amino groups.

6. The method for preparing Janus particles based on GMA monomer emulsion polymerization as described in claim 5, characterized in that, include: The PFC-PGMA composite particles described in claim 4 were dispersed in an NH3·H2O solution, ultrasonically dispersed, and then reacted in an oil bath. After the reaction was completed, the particles were centrifuged, washed, and dried to obtain the Janus particles based on GMA monomer emulsion polymerization.

7. The preparation method according to claim 6, characterized in that, The ratio of PFC-PGMA composite particles to NH3·H2O solution is 100~500mg:5-20mL; the mass fraction of NH3·H2O solution is 25~28wt%. The heating temperature for the oil bath reaction is 50~80℃; the heating time is 1~6h.

8. The application of Janus particles based on GMA monomer emulsion polymerization as described in claim 5 in oil-water emulsification.

9. A PFC-PGMA-NH2@Au Janus catalyst prepared based on the Janus particles of claim 5, characterized in that, The catalyst is spherical with a distinct phase boundary on the outside. One side contains carbon-fluorine bonds, and the other side contains gold nanoparticles.

10. The application of the PFC-PGMA-NH2@Au Janus catalyst of claim 9 in the catalytic reduction of nitro compounds.

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