Preparation method for accurately regulating and controlling PSS and APEG block copolymer and PEDOT (poly (3, 4-ethylenedioxythiophene)) dispersoid

Abstract

The invention discloses a method for regulating and controlling the block ratio and molecular weight of a PSS and APEG block polymer, which is characterized in that a reversible addition-fragmentation chain transfer polymerization (RAFT) method is adopted, and the method specifically comprises the following steps: (1) mixing an APEG monomer, an RAFT reagent and an initiator, and carrying out prepolymerization reaction at 60-80 DEG C to form an APEG active chain segment with the tail end of the RAFT reagent; and (2) adding a PSS monomer into the reaction system, and continuously carrying out polymerization reaction at 60-80 DEG C to form the APEG-b-PSS block polymer. And in the field of biological medicines, due to good dissolvability and biocompatibility, the polymer is more suitable for being used as a drug carrier. The accurate control of the drug release rate can be realized through the accurate block ratio and molecular weight control, the curative effect of the drug is improved, and the side effect is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis, and specifically relates to a method for regulating the block ratio and molecular weight of a PSS (sodium polystyrene sulfonate) and APEG (allyl polyethylene glycol) block polymer, and a method for preparing a PEDOT dispersion. Background Art

[0002] PSS (sodium polystyrene sulfonate) is a polymer with a rigid benzene ring structure. Sulfonate ions are present on its molecular chain, endowing the polymer with excellent hydrophilicity, ionic conductivity, and metal ion chelation. APEG (allyl polyethylene glycol) is a polymer based on polyethylene glycol with terminal allyl groups. The polyethylene glycol segments impart excellent water solubility, biocompatibility, and flexibility to the polymer. The allyl groups can participate in various chemical reactions, providing active sites for further modification and functionalization of the polymer.

[0003] When PSS and APEG are chemically linked to form a block polymer, the two distinct segments undergo microscopic phase separation within the molecule, endowing the block polymer with unique properties not possessed by a single polymer. For example, in aqueous solution, the hydrophilic segments of APEG tend to interact with water molecules, while the rigid segments of PSS aggregate to form a specific microstructure. This structure imparts surface activity to the block polymer, enabling it to self-assemble in solution into nanostructures such as micelles and vesicles.

[0004] Self-assembly is also a key property of PSS and APEG block copolymers. In selective solvents or under specific conditions, interactions between different segments can induce microphase separation, leading to the formation of regularly structured nanomaterials. This self-assembly capability allows for precise control of the size and shape of nanostructures when creating nanopatterns or nanotemplates, providing powerful support for the development of nanotechnology.

[0005] Furthermore, PSS and APEG block copolymers exhibit excellent biocompatibility, dispersibility, and stability. In the biomedical field, this excellent biocompatibility enables their use in biosensors and tissue engineering scaffolds. In materials science, their excellent dispersibility and stability help improve the processing performance and service life of materials.

[0006] The importance of precise control of block ratio and molecular weight

[0007] The block ratio and molecular weight have a crucial influence on the properties of PSS-APEG block copolymers. Variations in the block ratio directly affect the copolymer's self-assembly behavior and the resulting nanostructure morphology. Increasing the proportion of PSS segments results in a denser micelle core and improved micelle stability. Conversely, increasing the proportion of APEG segments enhances the hydrophilicity of the micelles and improves their dispersibility in aqueous solutions. Therefore, precise control of these parameters is crucial.

[0008] Molecular weight also plays a key role in the performance of copolymers. Lower molecular weight PSS and APEG block copolymers generally have better solubility and fluidity, making them easier to process and shape, but may have deficiencies in mechanical properties and stability. Higher molecular weight copolymers, on the other hand, have greater strength and stability but may be more difficult to process.

[0009] Currently, methods for regulating the block ratio and molecular weight of PSS and APEG block polymers mainly include living anionic polymerization, living cationic polymerization, and controlled free radical polymerization. However, these traditional methods have many limitations.

[0010] While living anionic polymerization can precisely control the structure and molecular weight distribution of polymers, it places extremely stringent requirements on reaction conditions. It must be carried out in an anhydrous and oxygen-free environment, and the purity of the initiator and monomers must be extremely high. This complicates the synthesis process and significantly increases costs. Furthermore, living anionic polymerization is applicable to a narrow range of monomers, making effective polymerization difficult for some monomers containing active hydrogen or other functional groups that are susceptible to reaction with anionic initiators.

[0011] Living cationic polymerization also faces similar challenges. The reaction conditions are harsh, and the stability of cationic initiators is poor, making side reactions more likely to occur. This makes it difficult to precisely control the structure and properties of the polymer. Furthermore, chain transfer and chain termination reactions in living cationic polymerization are difficult to inhibit, resulting in a broad molecular weight distribution and making it difficult to obtain block polymers with uniform molecular weight.

[0012] Controlled radical polymerization is a method that is currently widely used, such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer polymerization (RAFT). However, these methods also have some problems when regulating PSS and APEG block polymers. For example, ATRP requires the use of transition metal catalysts, and residual metal ions will have an adverse effect on the performance of the polymer, especially in fields such as biomedicine that require extremely high material purity. The removal of metal ions becomes a difficult problem. Although RAFT polymerization avoids the use of metal catalysts, the synthesis of RAFT reagents is relatively complicated, and impurities may be introduced during the polymerization process, affecting the quality of the polymer. In addition, whether it is ATRP or RAFT, there are certain difficulties in accurately controlling the block ratio of PSS and APEG. It is often necessary to conduct multiple experiments to explore the appropriate reaction conditions, which is time-consuming and labor-intensive. Summary of the Invention

[0013] The present invention aims to overcome the shortcomings of existing methods for regulating the block ratio and molecular weight of PSS and APEG block polymers, and to provide a method that is simple to operate, low in cost, and under mild reaction conditions, and can precisely regulate the block ratio and molecular weight of PSS and APEG block polymers, thereby improving the performance of the polymers and meeting the stringent requirements for material properties in various fields. By precisely controlling the block ratio and molecular weight, the PSS-APEG block polymers can maintain good solubility and biocompatibility while also possessing superior mechanical properties, thermal stability, and other specific properties, laying a solid foundation for their widespread application in fields such as biomedicine, electronic materials, and environmental protection.

[0014] The technical solution of the present invention is: a method for regulating the block ratio and molecular weight of PSS and APEG block polymers, using a reversible addition-fragmentation chain transfer polymerization (RAFT) method, specifically comprising the following steps:

[0015] (1) APEG monomer, RAFT agent and initiator are mixed and prepolymerized at 60-80°C to form an APEG active segment with a RAFT agent end; (2) PSS monomer is added to the above reaction system and polymerization is continued at 60-80°C to form an APEG-b-PSS block polymer.

[0016] The structure of the RAFT agent is ZC(S)-SR, Z is p-cyanophenylethyl, R is isopropylbenzene, and the molar ratio of the RAFT agent to the monomer is 1:50-1:200; the initiator is azobisisobutyronitrile, and its usage is 0.5%-2% of the total weight of the monomer.

[0017] The prepolymerization reaction time of the APEG monomer is 3-5 hours, and the polymerization reaction time after adding the PSS monomer is 8-24 hours.

[0018] The reaction process is as follows:

[0019]

[0020] The PSS and APEG block polymers prepared by the method described are described.

[0021] The PSS and APEG block polymers are used as drug carriers or tissue engineering scaffold materials in the field of biomedicine.

[0022] The PSS and APEG block polymers are used as lithium-ion battery separators or organic field-effect transistor materials in the field of electronic materials.

[0023] Beneficial effects of the present invention:

[0024] 1. In the present method, the block ratio of APEG and PSS is adjusted by controlling the prepolymerization reaction time of APEG monomer and the amount of PSS monomer added. The molecular weight of the polymer is controlled by adjusting the initiator concentration.

[0025] 2. Performance improvement: The PSS and APEG block polymers prepared by the method of the present invention have been significantly improved in performance. In terms of solubility, due to the appropriate ratio of the hydrophilic segments of APEG and PSS, the block polymer has good solubility in water and various organic solvents. Compared with polymers prepared by traditional methods, its dissolution rate is faster and its solubility is higher. In terms of mechanical properties, the precisely controlled block ratio and molecular weight make the interaction between polymer molecular chains more reasonable, forming a more regular microstructure, thereby improving the tensile strength, toughness and hardness of the polymer. For example, in some applications that need to withstand mechanical stress, such as the preparation of high-strength biodegradable stents, the PSS-APEG block polymers prepared by the present invention can exhibit better mechanical properties and meet the requirements of actual use. In terms of thermal stability, the thermal decomposition temperature of the polymer is significantly improved, and the structure and performance can be kept stable at higher temperatures. This is because the appropriate block ratio and molecular weight distribution enhance the interaction force between polymer molecular chains, restricting the movement of the molecular chains, thereby improving thermal stability. In the field of electronic materials, such as when used to prepare electronic packaging materials for use in high-temperature environments, good thermal stability can ensure the reliability and stability of the materials during use.

[0026] 3. Application Expansion: Improved performance opens up new application potential for this polymer in a wide range of fields. In the biopharmaceutical field, its excellent solubility and biocompatibility make it suitable as a drug carrier. Precise control of block ratio and molecular weight allows for precise regulation of drug release rates, improving drug efficacy and minimizing side effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The ratio of PSS to APEG blocks 1 H-NMR;

[0028] Figure 2 FT-IR and HPLC graphs of PSS-APEG; (a) FT-IR graph of PSS-APEG; (b) HPLC curve of PSS-APEG

[0029] Figure 3 The conductivity and stress-strain behavior of PEDOT:PSS-APEG; (a) conductivity change of PEDOT:PSS-APEG (undoped with DMSO), (b) stress-strain curve of PEDOT:PSS-APEG, (c) conductivity change after blending of PEDOT:PSS and PEDOT:PSS-APEG (doped with DMSO). DETAILED DESCRIPTION

[0030] Example 1:

[0031] Synthesis of poly(p-styrene sulfonic acid) with 34000:

[0032] Take 10.152g of NaSS and add it to 67.68g of DDI. Add 8.4mg of chain transfer agent to 10g of anhydrous ethanol and fully dissolve them under an inert nitrogen atmosphere at 70℃; evacuate and circulate nitrogen three times to completely dissolve 0.6168g of ACVA in 16.8g of deionized water and slowly add it dropwise to a four-necked flask. React at a constant temperature for 20h. Stop the reaction by rapid cooling and exposure to air, and cool to room temperature. Remove the residual initiator and any residual by-products of the reaction by dialysis for about 24h, and concentrate and dry to obtain a pink solid.

[0033] Example 2:

[0034] Synthesis of poly(p-styrene sulfonic acid)-APEG block copolymer (block ratio 2:1) with 36000:

[0035] 8.45 g of the solid of Example 1 was added to 50.7 g of DDI, and 4.2371 g of APEG was added to 50.7 g of water and fully dissolved under an inert nitrogen atmosphere at 70°C; vacuum nitrogen was circulated three times, 47.57 mg of ACVA was completely dissolved in 50.7 g of deionized water, and the mixture was slowly added dropwise to a four-necked flask. The reaction was kept at a constant temperature for 6 h, and the reaction was stopped by rapid cooling and exposure to air. The mixture was cooled to room temperature, and the residual initiator and any residual by-products of the reaction were removed by dialysis for about 24 h. The mixture was concentrated and dried to obtain a white solid. PSS-APEG was dissolved in water (0.25 g mL -1 ) and stirred on acidic cationic resin at room temperature for 6 h, then filtered through a 0.45 μm nylon syringe filter and dried under vacuum.

[0036] Example 3:

[0037] Synthesis of poly(p-styrenesulfonic acid)-APEG block copolymer (block ratio 1:1) with 41000:

[0038] 10.17 g of the solid of Example 1 was added to 61.02 g of DDI, and 11.898 g of APEG was added to 50.7 g of water and fully dissolved in an inert nitrogen atmosphere at 70 degrees. The mixture was evacuated and circulated with nitrogen three times to completely dissolve 47.57 mg of ACVA in 50.7 g of deionized water. The mixture was slowly added dropwise to a four-necked flask and reacted at a constant temperature for 6 hours. The reaction was stopped by rapid cooling and exposure to air, and cooled to room temperature. The residual initiator and any residual by-products of the reaction were removed by dialysis for about 24 hours, and the solid was concentrated and dried to obtain a yellow-white solid. PSS-APEG was dissolved in water (0.25 g mL -1 ) and stirred on acidic cationic resin at room temperature for 6 h, then filtered through a 0.45 μm nylon syringe filter and dried under vacuum.

[0039] Example 4:

[0040] Synthesis of poly(p-styrene sulfonic acid)-APEG block copolymer (block ratio 1:2) with 50000:

[0041] 10.47 g of the solid of Example 1 was added to 62.82 g of DDI, and 24.5 g of APEG was added to 73.5 g of water and fully dissolved under an inert nitrogen atmosphere at 70 degrees. The mixture was evacuated and circulated with nitrogen three times to completely dissolve 47.57 mg of ACVA in 50.7 g of deionized water. The mixture was slowly added dropwise to a four-necked flask and reacted at a constant temperature for 6 h. The reaction was stopped by rapid cooling and exposure to air, and cooled to room temperature. The residual initiator and any residual by-products of the reaction were removed by dialysis for about 24 h, and the solid was concentrated and dried to obtain a yellow-white solid. PSS-APEG was dissolved in water (0.25 g mL -1) and stirred on acidic cationic resin at room temperature for 6 h, then filtered through a 0.45 μm nylon syringe filter and dried under vacuum.

[0042] Example 5:

[0043] Synthesis of PEDOT:PSS-APEG aqueous dispersion:

[0044] 0.9 g of PSS-APEG was dissolved in 2.1 g of DDI water. Then, 17 g of DDI was added and further dissolved at room temperature. Subsequently, 0.04 g of Fe(SO) and 0.92 g of NaSO were added in sequence. Finally, 58 g of DDI was added to ensure complete dissolution. Finally, 0.38 g of EDOT was added to the reactor. After 24 hours of reaction, 20 g of cation and anion exchange resins were added to the reactor. Purification was carried out at room temperature for 6 hours. The mixture was then filtered through a 10 μm filter to obtain a dispersion.

[0045] Example 6:

[0046] Synthesis of PEDOT:PSS-APEG aqueous dispersion:

[0047] 1.45g of PSS-APEG was dissolved in 2.1g of DDI water. Then, 17g of DDI was added and further dissolved at room temperature. Subsequently, 0.04g of Fe(SO) and 0.92g of NaSO were added in sequence. Then, 58g of DDI was added to ensure complete dissolution. Finally, 0.38g of EDOT was added to the reactor. After 24 hours of reaction, 20g of cation and anion exchange resins were added to the reactor. Purification was carried out at room temperature for 6 hours. The mixture was then filtered through a 10μm filter to obtain a dispersion.

[0048] like Figure 3 As shown, the conductivity of the PEDOT:PSS-APEG film decreases with increasing APEG segment content, which is attributed to the inhibitory effect of the insulating APEG component on the carrier mobility of PEDOT:PSS. In contrast, the tensile strain of the composite film exhibits a non-monotonic dependence on APEG concentration, increasing significantly at low APEG loadings and decreasing sharply at high loadings. Notably, upon blending the APEG-modified system with the original PEDOT:PSS dispersion, the conductivity significantly recovers to a level comparable to that of the unmodified PEDOT:PSS. This recovery effect likely stems from the reconstruction of conductive PEDOT-rich domains during the blending process and the effective suppression of APEG-induced carrier scattering pathways.

Claims

1. A method for regulating the block ratio and molecular weight of a PSS and APEG block polymer, characterized in that: The reversible addition-fragmentation chain transfer (RAFT) polymerization method is adopted, which specifically includes the following steps: (1) APEG monomer, RAFT agent and initiator are mixed, and a prepolymerization reaction is carried out at 60-80°C to form an APEG active segment with a RAFT agent end; (2) PSS monomer is added to the above reaction system, and the polymerization reaction is continued at 60-80°C to form an APEG-b-PSS block polymer.

2. A method for regulating the block ratio and molecular weight of PSS and APEG block polymers according to claim 1, characterized in that: The structure of the RAFT agent is ZC(S)-SR, Z is p-cyanophenylethyl, R is isopropylbenzene, and the molar ratio of the RAFT agent to the monomer is 1:50-1:200; the initiator is azobisisobutyronitrile, and its usage is 0.5%-2% of the total weight of the monomer.

3. A method for regulating the block ratio and molecular weight of PSS and APEG block polymers according to claim 1, characterized in that: The prepolymerization reaction time of the APEG monomer is 3-5 hours.

4. A method for regulating the block ratio and molecular weight of PSS and APEG block polymers according to claim 1, characterized in that: The polymerization reaction time after adding PSS monomer is 8-24h.

5. The PSS and APEG block polymer prepared according to any one of claims 1 to 4.

6. Use of the PSS and APEG block polymer as claimed in claim 5 as a drug carrier or tissue engineering scaffold material in the field of biomedicine.

7. Use of the PSS and APEG block polymer as claimed in claim 5 as a lithium-ion battery separator or an organic field-effect transistor material in the field of electronic materials.

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