Surface-charged polymer nanoparticles, their synthesis methods and applications

Abstract

This application provides surface-charged polymer nanoparticles, their synthesis method, and applications. The synthesis method for the charged polymer nanoparticles includes: adding a thiocarbonate chain transfer agent, a charged monomer, an aromatic monomer containing at least two benzene rings, and an initiator to a mixture of water and an organic solvent to obtain a mixture; heating the mixture in a vacuum-sealed environment, and obtaining surface-charged polymer nanoparticles through a polymerization reaction and self-assembly process, wherein the charged monomer is a monomer with a single charge type.

Description

Technical Field

[0001] This application relates to the field of polymer nanomaterials technology, and in particular to a surface-charged polymer nanoparticle, its preparation method, and its application. Background Technology

[0002] Polymer nanoparticles are a class of polymer assemblies with nanoscale micromorphology and size distribution in the nano to micrometer range. They have shown great application value and development potential in many fields such as drug delivery, nanoreactors, Pickering emulsification, bioimaging and smart response materials.

[0003] Currently, the main methods for preparing polymer nanoparticles include solvent evaporation, thin-film hydration, microemulsion polymerization, and polymerization-induced self-assembly (PISA) technology. Different preparation strategies can yield polymer nanoparticles with varying microstructures and stability. However, existing techniques still face significant technical bottlenecks in preparing surface-charged polymer nanoparticles: morphology control is difficult, morphology transformation is poorly controllable, the resulting nanoparticles lack stability, surface-charged functional groups are easily embedded within the particles and not fully exposed, and the preparation process is cumbersome and difficult to scale up. Therefore, a method for preparing surface-charged polymer nanoparticles with controllable morphology and higher surface charge density is urgently needed, which is of great significance for meeting the high-end application needs of related fields. Summary of the Invention

[0004] In view of this, the main objective of this application is to provide surface-charged polymer nanoparticles, their preparation method, and their applications, in order to at least partially solve at least one of the aforementioned technical problems.

[0005] To achieve the above objectives, the technical solution of this application is as follows:

[0006] In one aspect of this application, a method for synthesizing surface-charged polymer nanoparticles is provided, comprising: adding a thiocarbonate chain transfer agent, a charged monomer, an aromatic monomer containing at least two benzene rings and an initiator to a mixture of water and an organic solvent to obtain a mixture; heating the mixture in a vacuum-sealed environment, and obtaining surface-charged polymer nanoparticles through a polymerization reaction and a self-assembly process, wherein the charged monomer is a monomer with a single charge type.

[0007] In another aspect of this application, a surface-charged polymer nanoparticle prepared by the above-described synthesis method is provided. The surface-charged polymer nanoparticle comprises a core formed by polymerization of an aromatic monomer containing at least two benzene rings and a charged polymer shell covering the core.

[0008] In another aspect of this application, the application of the above-mentioned surface-charged polymer nanoparticles in the preparation of at least one of drug carriers, antibacterial materials, and adsorption separation materials is provided.

[0009] According to the synthesis method of surface-charged polymer nanoparticles in this application, a single-charged monomer and an aromatic monomer containing at least two benzene rings are used as the main raw materials. Controlled polymerization and in-situ self-assembly are completed simultaneously in a one-pot process. During the polymerization process, the length ratio of the solubilizing charged segments to the solubilizing aromatic segments is controlled with the reaction, so that the polymer can self-assemble in an orderly manner in a mixture of water and organic solvent. At the same time, the dispersion stability is ensured by the electrostatic repulsion between the surface charge of the polymer nanoparticles and the charged polymer segments, and the π-π stacking effect between the benzene rings in the aromatic segments provides the driving force for the transformation of different morphologies. Surface-charged polymer nanoparticles with controllable morphology and high surface charge density are obtained. The process is simple and controllable and has good prospects for industrial application. Attached Figure Description

[0010] Figure 1 These are transmission electron microscope images of the negatively charged polymer nanoparticles prepared in Examples 1 to 3 of this application.

[0011] Figure 2 These are transmission electron microscope images of the surface-charged polymer nanoparticles prepared in Examples 4 to 6 of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to specific embodiments.

[0013] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0014] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0015] Common methods for preparing polymer nanoparticles include emulsion polymerization, precipitation polymerization, and dispersion polymerization. Among these, polymerization-induced self-assembly (PISA) is currently the main method for preparing morphology-controllable polymer nanoparticles. However, existing PISA techniques still face several insurmountable technical bottlenecks in preparing polymer nanoparticles with both surface functionalization and size uniformity. First, the route of surface modification through dispersion copolymerization of functional monomers tends to result in functional groups being embedded inside the particles, failing to be fully exposed and effectively utilized on the particle surface. Second, the route using macro-chain transfer agents (macro-CTAs) with functional groups as stabilizers relies on the chemical properties of the stabilizer chains, which directly determine the colloidal stability of the nanoparticles. In particular, cationic stabilizers, due to the strong electrostatic repulsion between molecular chains, typically only produce spherical nanoparticles, making it difficult to achieve controllable preparation of higher-order morphologies such as worm-like micelles and vesicles. In addition, existing related preparation techniques generally suffer from insufficient colloidal stability of nanoparticles, poor monodispersity of particle size, low surface charge density, and complex post-processing steps. Therefore, the preparation of polymer nanoparticles with precise and controllable morphology, uniform size, and fully functionalized surface based on PISA technology remains a technical problem that urgently needs to be solved in this field.

[0016] This study discovered that reversible addition-fragmentation chain transfer (RAFT) polymerization can utilize the polymerization-induced self-assembly (PISA) mechanism to prepare nanoparticles with different morphologies, such as spherical micelles, worm-like micelles, and vesicles. Based on this discovery, this application proposes a method for preparing surface-charged polymer nanoparticles, in which charged monomers and aromatic monomers are simultaneously polymerized and self-assembled under the action of an initiator. Specifically, the chain segments formed by the polymerization of charged monomers ensure the stability of the polymer assembly through electrostatic repulsion, effectively preventing aggregation; the chain segments formed by the polymerization of aromatic monomers promote rapid polymer nucleation through π-π stacking interactions, while also providing the driving force for the formation of different morphologies. This method is a one-step synthesis, with a simple and easily controllable process. The resulting nanoparticles have a charged surface, tunable particle size, and diverse morphologies, providing an efficient and convenient new method for the preparation of surface-charged polymer nanoparticles.

[0017] According to one aspect of this application, a method for synthesizing surface-charged polymer nanoparticles is provided, comprising: adding a thiocarbonate chain transfer agent, a charged monomer, an aromatic monomer containing at least two benzene rings and an initiator to a mixture of water and an organic solvent to obtain a mixture; heating the mixture in a vacuum-sealed environment, and obtaining surface-charged polymer nanoparticles through a polymerization reaction and a self-assembly process, wherein the charged monomer is a monomer with a single charge type.

[0018] The method for preparing surface-charged polymer nanoparticles in this application employs a one-pot method to combine charged monomers with aromatic monomers containing at least two benzene rings, efficiently preparing the target nanoparticles. During the polymerization reaction, the solubilophilic charged monomer regulates the polymerization of the solubilizer-sensitive aromatic monomer, gradually forming statistical polymer assemblies. As the polymerization reaction progresses, the length ratio of the solubilizer-to-solophilic chain segments continuously increases, and the statistical polymer undergoes self-assembly in the selective solvent, ultimately forming surface-charged polymer nanoparticles. The strong electrostatic interaction between the charged monomer chain segments effectively prevents irreversible aggregation common in traditional processes through electrostatic repulsion. Furthermore, the strong π-π stacking interaction between the benzene ring structures of the aromatic monomer chain segments promotes rapid polymer nucleation, significantly improving the nanoparticle forming efficiency, and provides an effective driving force for the formation of higher-order morphologies, successfully producing vesicles—high-order morphology polymer nanoparticles distinct from micelles.

[0019] According to embodiments of this application, the molar ratio of the thiocarbonate chain transfer agent, charged monomer, aromatic monomer, and initiator is 1:(20-100):(60-140):0.20. For example, it can be 1:20:60:0.2, 1:40:70:0.2, 1:60:80:0.2, 1:80:100:0.2, 1:80:120:0.2, 1:100:140:0.2, etc. By precisely controlling the molar ratio of the thiocarbonate chain transfer agent, charged monomer, aromatic monomer, and initiator, this application achieves a balance between rapid nucleation and uniform growth of the polymer during polymerization. This ensures the colloidal stability of the nanoparticles and supports the controllable synthesis of different morphologies such as spherical micelles, worm-like micelles, and vesicles, fundamentally ensuring the morphological stability and batch-to-batch uniformity of the polymer nanoparticles.

[0020] According to embodiments of this application, the thiocarbonate chain transfer agent includes any one of 4-cyanopentanoic acid trithiobenzoic acid, 4-cyano-4-(phenylthiocarbamoylthio)pentanoic acid, and dithiobenzoic acid cyanoisopropyl ester. The thiocarbonate chain transfer agent exhibits good compatibility with water and organic solvent mixtures, and good compatibility with charged monomers, aromatic monomers, and initiators, without side reactions. The thiocarbonate chain transfer agent can regulate the polymerization process, achieving stable, controllable free radical polymerization, ensuring uniform polymer molecular weight distribution, and controlling the length ratio of solvophilic charged segments to solvophobic aromatic segments, providing stable and controllable reaction conditions for the uniform nucleation and orderly growth of surface-charged polymer nanoparticles.

[0021] The charged monomers include any one of methacryloyloxyethyltrimethylammonium chloride and potassium propyl 3-sulfonate methacrylate. The charged monomers are of a single charge type, carrying the same charge, and can be either positively or negatively charged. Selecting a single charge type monomer enables the formation of a uniformly distributed layer of the same charge on the surface of the charged polymer nanoparticles. This charge layer can prevent aggregation of the assemblies through electrostatic interactions, thereby ensuring good stability of the surface-charged polymer nanoparticles.

[0022] Aromatic monomers include either ethyl 2-(methacryloyloxy)anthracene-9-carboxylate or ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate. If the aromatic monomer contains only a single benzene ring, the insufficient number of benzene rings weakens the intermolecular π-π stacking interaction. This reduces the nucleation rate of polymer nanoparticles and, moreover, the weak π-π stacking interaction cannot provide sufficient driving force for the formation of higher-order vesicle morphologies, making it difficult to achieve the controllable preparation of the target higher-order morphology. Conversely, if the aromatic monomer contains too many benzene rings, the solubility of the monomer in a mixture of water and organic solvents will significantly decrease, disrupting the homogeneity of the polymerization reaction system and hindering the controllable synthesis of surface-charged polymer nanoparticles. Therefore, this application preferably uses aromatic monomers containing 2-3 benzene rings. This ensures good solubility of the aromatic monomer in the reaction system while providing sufficient π-π stacking interaction for rapid polymer nucleation, simultaneously providing an effective driving force for the formation of higher-order morphologies, ultimately achieving the stable and controllable preparation of surface-charged polymer nanoparticles.

[0023] The initiator includes any one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate. The decomposition temperature of the above-mentioned azo initiators is suitable for the heating reaction temperature (50~90℃) of this application. They exhibit stable thermal decomposition, controllable free radical release, and can initiate RAFT copolymerization of charged monomers and aromatic monomers. They also have good compatibility with the reaction system and stable initiation efficiency.

[0024] The organic solvent includes at least one of ethanol, methanol, isopropanol, dimethyl sulfoxide, and tetrahydrofuran, wherein the mass ratio of organic solvent to water is (4~6):(6~4), for example, 4:6, 5:5, 6:4, etc. The mass ratio of organic solvent to water can regulate the polymerization reaction process and determine the dissolution environment, polymerization kinetics, and polymer self-assembly behavior of the reaction system. When the proportion of organic solvent is too high and the proportion of water is too low, the solubilizing effect of the hydrophobic segments of the polymer will be weakened, the nucleation time of the polymerization process will be prolonged, and the nanoparticle size distribution will be uneven, or even irreversible agglomeration of particles will be triggered. Conversely, if the proportion of water is too high and the proportion of organic solvent is too low, the solubility of the system will be reduced, especially the dissolution of aromatic monomers containing polybenzene ring structures will be limited. This will not only reduce the polymerization reaction efficiency, but also cause the surface structure of polymer nanoparticles with dotted surfaces to be uneven, ultimately deteriorating the morphology controllability and application performance of polymer nanoparticles.

[0025] According to embodiments of this application, the heating temperature is 50~90℃, for example, 50℃, 60℃, 70℃, 80℃, 90℃, etc., and the time is 10~24 h, for example, 10 h, 15 h, 19 h, 21 h, 24 h, etc. A suitable temperature range matches the thermal decomposition range of the initiator in this application, enabling uniform and stable release of free radicals. This avoids problems such as insufficient initiation efficiency, slow polymerization rate, and low monomer conversion rate at low temperatures, which prevent the completion of the preset chain segment structure design. Simultaneously, it avoids defects such as uncontrolled polymerization caused by excessively high temperatures, excessively wide molecular weight distribution due to chain transfer agent deactivation, and disordered morphology. A suitable reaction time ensures high conversion rates of charged and aromatic monomers, achieving the designed ratio of solvophilic charged segments to solvophobic aromatic segments, providing a sufficient reaction window for the ordered self-assembly and morphology control of polymer segments.

[0026] According to embodiments of this application, the solid content of the charged polymer nanoparticles is 10% to 21%, for example, it can be 10%, 12%, 14%, 16%, 18%, 21%, etc. The method for synthesizing surface-charged polymer nanoparticles of this application can stably produce polymer nanoparticle products with higher solid content while ensuring controllable morphology and colloidal stability of the polymer nanoparticles, thereby increasing the effective concentration of surface-charged polymer nanoparticles per unit volume of the reaction system. The main reasons are as follows: The one-pot synthesis route, coupled with RAFT controlled polymerization and PISA, allows for simultaneous polymerization and in-situ polymer self-assembly. This overcomes the limitations of traditional post-assembly methods, which require dilution and dialysis, resulting in low upper limits for solid content. High-concentration products can be obtained directly without additional post-treatment to reduce concentration. The hydrophilic charged segments formed by the simultaneous polymerization of charged monomers spontaneously accumulate on the nanoparticle surface, creating a high density of like charges. Strong electrostatic repulsion effectively prevents irreversible agglomeration of nanoparticles at high solid contents, ensuring the colloidal stability of the system at high concentrations. The π-π stacking interaction between aromatic monomer segments provides a stable driving force for polymer nucleation and morphology evolution, enabling the self-assembly process to proceed smoothly and orderly even at high monomer concentrations, avoiding morphological collapse and uneven particle size distribution at high solid contents. This method enables the stable mass production of nanoparticles, providing an effective approach for subsequent industrial applications.

[0027] According to embodiments of this application, heating the mixture in a vacuum-sealed environment includes performing at least three cycles of freezing, vacuuming, and thawing on the mixture, followed by vacuum sealing. This process removes dissolved oxygen and trace volatile impurities from the mixture system through multiple cycles, eliminating the inhibitory and quenching side effects of oxygen on free radical polymerization, ensuring the stable progress of RAFT (Rapid Active Free Radical) polymerization. Multiple cycles also achieve deeper deoxygenation, avoiding problems such as uncontrolled polymerization, uneven molecular weight distribution, and monomer conversion fluctuations caused by trace residual oxygen. Combined with subsequent vacuum sealing, external oxygen infiltration is prevented, providing a stable oxygen-free environment for the polymerization reaction and in-situ self-assembly process. This effectively avoids defects such as disordered nanoparticle morphology, uneven particle size distribution, and poor batch repeatability caused by oxygen interference, ultimately achieving stable and controllable preparation of surface-charged polymer nanoparticles.

[0028] According to another aspect of this application, a surface-charged polymer nanoparticle prepared by the above-described synthesis method is provided. The surface-charged polymer nanoparticle comprises a core formed by polymerization of an aromatic monomer containing at least two benzene rings and a charged polymer shell covering the core.

[0029] According to embodiments of this application, the surface-charged polymer nanoparticles prepared by the above-described synthesis method have a core-shell structure, wherein the core is formed by the polymerization of an aromatic monomer containing at least two benzene rings, and the shell is composed of charged polymer segments covering the core. This core-shell structure enables the nanoparticles to possess both excellent structural and colloidal stability: the aromatic segment core effectively enhances the structural strength of the nanoparticles through the π-π stacking interaction between multiple benzene rings, providing support for the formation and stability of higher-order morphologies; the surface-charged polymer shell can impart a high-density surface charge to the nanoparticles, significantly inhibiting nanoparticle aggregation through electrostatic repulsion between segments and particles, greatly improving their dispersion stability and particle size uniformity in solution. Simultaneously, the clear functional division of the core and shell provides a stable and reliable material basis for subsequent functional applications.

[0030] According to embodiments of this application, the morphology of surface-charged polymer nanoparticles includes any one of micelles, worm-like structures, and vesicles. Through the synergistic effect of π-π stacking of aromatic segments and electrostatic repulsion of charged segments, this application overcomes the limitation that traditional charged systems are mostly spherical in shape, achieving flexible control and stable synthesis of various high-order morphologies. Different morphologies can be adapted to diverse application scenarios such as targeted transport, nanocarriers, and functional assembly, broadening the applicability and value of surface-charged polymer nanoparticles. Simultaneously, the morphology exhibits good uniformity and strong controllability, providing a stable and reliable structural foundation for their efficient application in various fields.

[0031] According to embodiments of this application, the surface-charged polymer nanoparticles include surface-negatively charged polymer nanoparticles or surface-positively charged polymer nanoparticles. The zeta potential value of the surface-negatively charged polymer nanoparticles is less than -60 mV, for example, it can be -65 mV, -70 mV, -75 mV, -80 mV, -85 mV, etc.; the zeta potential value of the surface-positively charged polymer nanoparticles is greater than 50 mV, for example, it can be 55 mV, 60 mV, 65 mV, 70 mV, 75 mV, etc.

[0032] According to the embodiments of this application, the aforementioned high Zeta potential value indicates that the surface charged polymer nanoparticles of this application have a high density and abundance of charge distribution. On the one hand, the strong electrostatic repulsion between particles can effectively suppress aggregation and sedimentation, significantly improving the dispersion stability and long-term stability of the surface charged polymer nanoparticles in solution. On the other hand, it can greatly enhance the electrostatic interaction and adsorption binding ability between the surface charged polymer nanoparticles and the target substance, making them more efficient and effective in adsorption, separation, loading and other application scenarios.

[0033] In some specific embodiments, the particle size of the surface-charged polymer nanoparticles can be 50–600 nm, for example, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, etc. By precisely controlling the particle size, the nanoparticles can be adapted to the needs of different application scenarios. Simultaneously, the prepared polymer nanoparticles can exhibit various morphologies such as micelles, worm-like structures, and vesicles. Different morphologies can be controllably prepared by adjusting the degree of polymerization (DP value) of the monomers. The diverse morphological structures endow the polymer nanoparticles with excellent multifunctional properties, giving them unique application value and broad application prospects in multiple high-tech fields such as catalysis, medical detection, drug delivery, and environmental remediation.

[0034] According to another embodiment of this application, the above-mentioned surface-charged polymer nanoparticles are provided for use in the preparation of at least one of drug carriers, antibacterial materials, and adsorption separation materials.

[0035] The surface-charged polymer nanoparticles prepared in this application possess unique advantages such as controllable morphology, high surface charge density, tunable particle size, and well-defined core-shell structure, making them widely applicable in various fields including drug carriers, antibacterial materials, adsorption and separation materials, and environmental remediation. In the biomedical field, high aspect ratio worm-like micelles can prolong in vivo blood circulation time and improve tumor tissue accumulation efficiency, meeting the needs of targeted drug delivery; vesicle structures can achieve simultaneous encapsulation of hydrophilic and hydrophobic drug molecules, solving the problem of synergistic delivery of different types of drugs; simultaneously, the surface charge endows the nanoparticles with excellent antibacterial activity, achieving an inhibition rate of over 95% against Escherichia coli and Staphylococcus aureus. Adding them to coating systems can provide an efficient and feasible core raw material for the development of antibacterial coatings. In the field of environmental remediation, these nanoparticles can efficiently adsorb and remove pollutants with opposite charges in water by means of electrostatic interaction of high-density surface charges. When used as a flocculant in the treatment of papermaking wastewater and urban sewage, compared with electrically neutral nanoparticles, they have higher flocculation efficiency and a wider pH range, which can be adapted to the treatment needs of different water qualities and show good application potential.

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments. Unless otherwise specified, all methods described in the embodiments are conventional and can be performed according to the techniques or conditions described in the literature or the product manual.

[0037] Example 1:

[0038] Example 1 of this application provides a method for synthesizing negatively charged polymer nanoparticles with micelle morphology, comprising the following steps.

[0039] 4-Cyanopentanoic acid trithiobenzoic acid (PETTC) (1.22 mg, 3.60 mg) 0.36 mmol), potassium propyl 3-sulfonate methacrylate (SPMAPS) (88.68 mg, 0.36 mmol), ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate (MAENC) (61.41 mg, 0.22 mmol), azobisisobutyronitrile (AIBN) (0.12 mg, 0.72 mmol), potassium propyl methacrylate (SPMAPS) (88.68 mg, 0.36 mmol), ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate (MAENC) (61.41 mg, 0.22 mmol), ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate (AIBN) (0.12 mg, 0.72 mmol), potassium propyl methacrylate (SPMAPS) (88.68 mg, 0.36 mmol 1 mol) was added together with 1000 mg of an aqueous ethanol solution (the mass ratio of ethanol to water was 4:6) and mixed to obtain a mixture.

[0040] The mixture was added to a sealed tube containing a magnetic magnet. After three cycles of freezing-vacuuming-thawing, the tube was vacuum-sealed and the reaction was carried out in a 70°C oil bath for 10 hours. The reaction formula is shown below.

[0041]

[0042] After the reaction was completed, the polymerization reaction was quenched by cooling to prepare micelle particles 1-1 with a target degree of polymerization of 100 and negative surface charge.

[0043] Example 2

[0044] Example 2 of this application provides a method for synthesizing surface-negatively charged polymer nanoparticles with a worm-like morphology. The difference from Example 1 is that surface-negatively charged polymer nanoparticles 1-2 with a target degree of polymerization of 90 are prepared. All other preparation processes for the surface-negatively charged polymer nanoparticles in Example 2 are the same as in Example 1.

[0045] Example 3

[0046] Example 3 provides a method for synthesizing surface-negatively charged polymer nanoparticles with vesicle morphology. The difference from Example 1 is that surface-negatively charged polymer nanoparticles 1-3 with a target degree of polymerization of 80 are prepared. All other preparation processes for the surface-negatively charged polymer nanoparticles in Example 3 are the same as in Example 1.

[0047] The negatively charged polymer nanoparticles obtained in Examples 1 to 3 were diluted to 0.50 mg / g in an aqueous ethanol solution and then characterized by transmission electron microscopy (TEM).

[0048] Figure 1 These are transmission electron microscope images of the negatively charged polymer nanoparticles prepared in Examples 1 to 3 of this application.

[0049] like Figure 1 As shown, the morphology of negatively charged polymer nanoparticles 1-1 is micelles; the morphology of negatively charged polymer nanoparticles 1-2 is worm-like; and the morphology of negatively charged polymer nanoparticles 1-3 is vesicles. This indicates that by controlling the degree of polymerization of the monomers and the reaction parameters, three types of negatively charged polymer nanoparticles with different morphologies were successfully prepared.

[0050] Example 4:

[0051] Example 4 of this application provides a method for synthesizing positively charged polymer nanoparticles, including the following steps.

[0052] 4-Cyanopentanoic acid trithiobenzoic acid (PETTC) (1.22 mg, 3.60 mg) 1 mol), methacryloyloxyethyltrimethylammonium chloride (MATAC) (119.64 mg, 0.58 mmol), ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate (MAENC) (81.88 mg, 0.29 mmol), azobisisobutyronitrile (AIBN) (0.12 mg, 0.72 mmol), methacryloyloxyethyltrimethylammonium chloride (MATAC) (119.64 mg, 0.58 mmol), ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate (MAENC) (81.88 mg, 0.29 mmol), ethyl azobisisobutyronitrile (AIBN) (0.12 mg, 0.72 mmol), ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate (MAENC) 1 mol) was added together with 1000 mg of an aqueous ethanol solution (the mass ratio of ethanol to water was 4:6) and mixed to obtain a mixture.

[0053] The mixture was added to a sealed tube containing a magnetic magnet. After three cycles of freezing-vacuuming-thawing, the tube was vacuum-sealed and the reaction was carried out in a 70°C oil bath for 10 hours. The reaction formula is shown below.

[0054]

[0055] After the reaction was completed, the polymerization reaction was quenched by cooling to prepare surface positively charged polymer nanoparticles 2-1 with a target degree of polymerization of 80.

[0056] Example 5:

[0057] Example 5 of this application provides a method for synthesizing surface-positively charged polymer nanoparticles. The difference from Example 4 is that surface-positively charged polymer nanoparticles 2-2 with a target degree of polymerization of 90 are prepared. All other preparation processes for the surface-positively charged polymer nanoparticles in Example 5 are the same as in Example 4.

[0058] Example 6:

[0059] Example 6 of this application provides a method for synthesizing surface-positively charged polymer nanoparticles. The difference from Example 4 is that surface-positively charged polymer nanoparticles 2-3 with a target degree of polymerization of 140 are prepared. All other preparation processes for the surface-positively charged polymer nanoparticles in Example 6 are the same as in Example 4.

[0060] Figure 2 These are transmission electron microscope images of the positively charged polymer nanoparticles prepared in Examples 4 to 6 of this application.

[0061] like Figure 2 As shown, the morphology of positively charged polymer nanoparticles 2-1 is micelles; the morphology of positively charged polymer nanoparticles 2-2 is worm-like; and the morphology of positively charged polymer nanoparticles 2-3 is vesicles. This indicates that by controlling the degree of polymerization of the monomers and the reaction parameters, three types of positively charged polymer nanoparticles with different morphologies were successfully prepared.

[0062] Dynamic light scattering (DLS) particle size and zeta potential were measured on the surface-charged polymer nanoparticles prepared in Examples 1 to 6. Table 1 shows the DLS particle size and zeta potential data of the cationic polymer microspheres prepared in Examples 1 to 6.

[0063] Table 1

[0064]

[0065] As shown in Table 1, the Zeta potential values ​​of the surface-charged polymer nanoparticles prepared in Examples 1 to 6 of this application are all above 50 mV, indicating that they have strong system stability.

[0066] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for synthesizing surface-charged polymer nanoparticles, characterized in that, include: A mixture is prepared by adding a thiocarbonate chain transfer agent, a charged monomer, an aromatic monomer containing at least two benzene rings, and an initiator to a mixture of water and an organic solvent. In a vacuum-sealed environment, the mixture is heated, and through polymerization and self-assembly processes, surface-charged polymer nanoparticles are obtained, wherein... The charged individual is a single-charge type individual.

2. The synthesis method according to claim 1, characterized in that, The molar ratio of the thiocarbonate chain transfer agent, the charged monomer, the aromatic monomer containing at least two benzene rings, and the initiator is 1:(20-100):(60-140):0.

20.

3. The synthesis method according to claim 1, characterized in that, The thiocarbonate chain transfer agent includes any one of 4-cyanopentanoic acid trithiobenzoic acid, 4-cyano-4-(phenylthiocarbamoylthio)valerate, and dithiobenzoic acid cyanoisopropyl ester. The charged monomer includes any one of methacryloyloxyethyltrimethylammonium chloride and potassium salt of 3-sulfonate methacrylate. The aromatic monomers include any one of: ethyl 2-(methacryloyloxy)anthracene-9-carboxylate and ethyl 2-(methacryloyloxy)naphthalene-1-carboxylate; The initiator includes any one of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate; The organic solvent includes at least one of ethanol, methanol, isopropanol, dimethyl sulfoxide, and tetrahydrofuran, wherein the mass ratio of the organic solvent to water is (4~6):(6~4).

4. The synthesis method according to claim 1, characterized in that, The heating temperature is 50~90℃, and the time is 10~15 h.

5. The synthesis method according to claim 1, characterized in that, The charged polymer nanoparticles have a solid content of 10% to 21%.

6. The synthesis method according to any one of claims 1 to 5, characterized in that, Heating the mixture in a vacuum-sealed environment includes: After performing at least three cycles of freezing, vacuuming, and thawing on the mixture, a vacuum sealing process is performed.

7. A surface-charged polymer nanoparticle prepared by the synthesis method according to any one of claims 1 to 6, characterized in that, The surface-charged polymer nanoparticles comprise a core formed by the polymerization of an aromatic monomer containing at least two benzene rings and a charged polymer shell covering the core.

8. The surface-charged polymer nanoparticles according to claim 7, characterized in that, The morphology of the surface-charged polymer nanoparticles includes any one of micelles, worm-like structures, and vesicles.

9. The surface-charged polymer nanoparticles according to claim 7, characterized in that, The surface-charged polymer nanoparticles include negatively charged polymer nanoparticles or positively charged polymer nanoparticles, wherein... The Zeta potential of the negatively charged polymer nanoparticles on the surface is less than -60 mV; The zeta potential of the positively charged polymer nanoparticles on the surface is greater than 50 mV.

10. The application of surface-charged polymer nanoparticles as described in any one of claims 7 to 9 in the preparation of at least one drug carrier, antibacterial material, or adsorption separation material.

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