Patterned PEDOT / PSS conductive coating with stable wet environment as well as preparation method and application of patterned PEDOT / PSS conductive coating

Abstract

The invention discloses a patterned PEDOT / PSS conductive coating with stable wet environment and a preparation method and application thereof, and the preparation method of the coating comprises the following steps: dissolving polycations, zwitterionic monomers, double-bond silane and an initiator to obtain a solution component A, and diluting PEDOT / PSS as a solution component B; and depositing the component A and the component B on the surface of a substrate covered with a patterned mask plate through double-channel ultrasonic atomization spraying to obtain the coating. According to the invention, the polycation, the zwitterionic monomer and the double-bond silane are taken as the component A, and the PEDOT / PSS is combined to prepare the conductive coating, so that the coating has extremely high wet environment stability, can ensure that the coating does not fall off in a physiological environment, has excellent biocompatibility and immunocompatibility, and can improve the long-term performance of implantable bioelectronics.

Description

Technical Field

[0001] The present invention relates to the technical field of medical coating materials, and in particular to a patterned PEDOT / PSS conductive coating that is stable in a wet environment, and a preparation method and application thereof. Background Art

[0002] Conductive polymers, due to their excellent electrical conductivity, mechanical flexibility, and biocompatibility, hold great potential for application in bioelectronics. Materials such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polypyrrole (PPy), and polyaniline (PAni), with their unique electrical properties, are widely used in flexible bioelectrodes, neural interfaces, cardiac sensors, electronic skin, and implantable medical devices. These materials operate stably at low potentials and enable effective signal transmission with human tissue, playing a key role in applications such as brain-computer interfaces, pacemakers, and electrical stimulation therapy. However, these conductive polymers exhibit inherent limitations in humid physiological environments, particularly during long-term use, often exhibiting poor substrate adhesion and stability. Due to water permeation and delamination of the interfacial layer, the conductive layer is prone to delamination, swelling, and even shedding, severely impacting device reliability and lifespan. Therefore, improving the adhesion, stability, and durability of conductive polymers in complex physiological environments remains a key challenge in current bioelectronic materials research.

[0003] In addition, high-resolution patterning of conductive coatings remains a technical challenge in the field of bioelectronics. Bioelectronic devices often require patterned structures with millimeter-to-nanometer precision to optimize their electrical performance, biocompatibility, and interface matching between the device and biological tissue. However, most current PEDOT:PSS coating fabrication methods have many limitations, such as the complex steps and long processing cycles of traditional photolithography and template fabrication processes, and are difficult to apply to large areas and flexible substrates. In addition, some patterning methods rely on chemical cross-linking or additive-induced processes, and these chemical reagents often have certain cytotoxicity and require a long time to detoxify, limiting their direct application in the biomedical field. Therefore, the development of a simple, efficient, non-toxic and high-resolution PEDOT:PSS hydrogel patterning process is crucial for the fabrication of bioelectronic devices.

[0004] CN104212243A discloses a method for preparing a PEDOT / PSS conductive ink and coating. A thickener is added to an acidic or neutralized PEDOT / PSS dispersion to achieve the desired viscosity. These conductive inks are then applied to form a PEDOT / PSS conductive coating. However, this coating has almost no interaction with the substrate and is prone to detachment, causing device failure.

[0005] CN117904681A discloses a method for preparing a PEDOT conductive coating on an aluminum alloy surface. An anionic electrolyte and prepolymerized monomers are dissolved in acetonitrile to prepare a coating polymerization solution. A surface-treated aluminum alloy substrate is then immersed in the deoxygenated coating polymerization solution. The output current density is adjusted to quickly break down the oxide film on the aluminum alloy surface. PEDOT is then rapidly and uniformly deposited on the substrate surface, resulting in a dense, smooth PEDOT coating. However, this electrochemically deposited PEDOT has drawbacks such as easy dopant deintercalation, molecular chain degradation, poor environmental tolerance, insufficient substrate adhesion, and low process repeatability. Furthermore, it is not possible to achieve high-resolution patterning. Summary of the Invention

[0006] This invention addresses the poor stability of PEDOT / PSS conductive coatings in wet environments and the difficulty in high-resolution patterning. It provides a method for preparing a patterned PEDOT / PSS conductive coating that is stable in wet environments. The PEDOT / PSS conductive coating prepared by this method exhibits excellent interfacial adhesion to the substrate, maintaining stability under harsh conditions. Furthermore, its high-resolution patterning capability (<20 μm) gives it potential for application in the field of bioelectronics.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing a patterned PEDOT / PSS conductive coating that is stable in a wet environment comprises the following steps: Step 1, performing plasma or ozone activation treatment on the substrate; Step 2: dissolving the polycation, zwitterionic monomer, double bond silane and initiator to obtain solution component A, and diluting PEDOT / PSS to obtain solution component B; Step 3, depositing component A and component B on the surface of a substrate covered with a patterned mask through dual-channel ultrasonic atomization spraying to obtain a coating; Step 4: polymerizing the substrate containing the coating under saturated humidity to obtain the patterned PEDOT / PSS conductive coating.

[0008] The PEDOT / PSS conductive polymer used in the present invention contains a large amount of polyanion electrolyte PSS. By introducing polycations, these strong anions can be promoted to cross-link through electrostatic interactions. In addition, the surface of the substrate after plasma treatment has a large amount of negative charge, which can be fully combined with the polycations, further enhancing the non-covalent interaction between the coating and the substrate.

[0009] The double-bonded silane and zwitterionic monomers in the system can be polymerized by initiators to form polyzwitterions. On the one hand, the double-bonded silane introduces a covalent interaction between the substrate and the coating. At the same time, the anion-π interaction between the polyzwitterion and PSS further stabilizes the coating. By combining ultrasonic spraying and mask plates, the preparation of patterned coatings with a maximum accuracy of 20μm can be achieved, which can be applied to the preparation of various types of bioelectronics, including brain-computer interface electrodes, pacemaker electrodes, electrical stimulation therapy electrodes, etc.

[0010] More importantly, the polyzwitterions used in this invention exhibit excellent immunocompatibility, enhancing the overall compatibility of the coating. This helps prevent foreign body reactions (FBRs), which can isolate implants from the body and contribute to bioelectronic failure. Overall, this PEDOT / PSS conductive coating, characterized by its stability, biocompatibility, and high-precision patterning, holds great promise for future applications.

[0011] The polycation includes any one or more of chitosan, polyethyleneimine, polydimethyldiallylammonium chloride, polyallylamine hydrochloride, polylysine, polyquaternary ammonium salts and copolymers or derivatives thereof; The zwitterionic monomer includes one or more of sulfobetaine methacrylate, carboxybetaine methacrylate, and methacryloyloxyethyl phosphorylcholine; The double bond silane includes one or more of 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and allyltriethoxysilane; The initiator includes one or more of ammonium persulfate, potassium persulfate, azodimethylvaleronitrile dihydrochloride, and azodimethylpropyleneamine dihydrochloride.

[0012] In the solution component A, the mass fraction of the polycationic component is 0.01-1% of the total solution mass, the mass fraction of the zwitterionic monomer is 0.5-3% of the total solution mass, the mass fraction of the double bond silane is 0.01-0.1% of the total solution mass, and the mass fraction of the initiator is 0.01-0.1% of the total solution mass.

[0013] In the solution component B, the mass fraction of PEDOT / PSS is 0.1-0.5 wt %, preferably, the mass fraction of PEDOT / PSS is 0.2-0.4 wt %.

[0014] The solvents of solution component A and solution component B include one or more of water and ethanol.

[0015] Preferably, the solvent is a water / ethanol mixed solvent, wherein the volume ratio of water to ethanol is 1:1-3; Preferably, a small amount of DMSO is added before diluting the PEDOT / PSS to improve the conductivity and stability of the coating. The amount of DMSO added is 5-20% of the volume of the PEDOT / PSS solution.

[0016] In step 3, the flow rates of component A and component B are each 5-100 μL / min; the flow rate ratio of component A to component B is 1:1-10. Preferably, the flow rate ratio of component A to component B is 1:2-8, and more preferably, the flow rate ratio is 1:2-6. The more component A, the better the coating stability, but the coating conductivity decreases. The more component B, the better the conductivity, but the stability decreases accordingly.

[0017] In step 3, the temperature of the substrate during the spraying process is 50-70° C. Within this temperature range, the volatile solvent in the system evaporates rapidly to promote rapid and thorough mixing of components A and B and to promote polymerization of the zwitterionic monomer.

[0018] In step 4, polymerization is performed by allowing the coated substrate to stand at 70-90°C in saturated humidity for 1-4 hours. This is done to promote coupling between the silane coupling agent and the substrate, or between the silane coupling agents, to form crosslinking points. It also promotes further polymerization of the SBMA monomer and improves conversion.

[0019] The substrate comprises any one of the following materials: (1) Metal materials: any one of stainless steel, titanium and its alloys, cobalt-based alloys, nickel-titanium alloys, magnesium and its alloys, zinc and its alloys, iron and its alloys; or, (2) Inorganic materials: any one of glass, silicon dioxide, titanium dioxide, carbon materials, silicon, and titanium nitride; or (3) Polymer materials: any of polyester, polyethylene, polypropylene, polytetrafluoroethylene, polyvinyl chloride, polystyrene and their copolymers or derivatives.

[0020] Preferably, the substrate material is at least one of silicone rubber, polyester, and polyurethane, all of which are commonly used materials for implantable bioelectronics.

[0021] In step 1, the plasma or ozone activation time is 1 to 60 minutes. The activation treatment is to increase the hydroxyl density on the substrate surface, which is more conducive to the subsequent grafting of siloxane, and to construct a negatively charged surface to promote non-covalent binding of polycations to the surface.

[0022] The present invention also provides a wet environment stable patterned PEDOT / PSS conductive coating prepared by the preparation method.

[0023] The present invention also provides the use of the patterned PEDOT / PSS conductive coating in preparing a bioelectrode.

[0024] Preferably, the bioelectrode is an implantable bioelectrode, such as a brain electrode, a pacemaker electrode, an electrical stimulation therapy electrode, etc.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present invention, polycation, zwitterionic monomer, and double-bonded silane are used as component A, and PEDOT / PSS is combined to prepare a conductive coating. The coating has extremely high stability in a wet environment, can ensure that the coating does not fall off in a physiological environment, and exhibits excellent electrochemical stability and can be used for a long time.

[0026] (2) The present invention adopts dual-channel ultrasonic atomization spraying technology to successfully realize the preparation of high-precision patterned PEDOT / PSS conductive coating. After component A and component B are treated by ultrasonic atomization, they will spontaneously agglomerate to form uniform micro-droplets during the spraying process. This special form of droplets can accurately pass through the fine structure of the high-precision mask and finally deposit on the surface of the substrate to form a patterned coating. Its accuracy can be stably controlled at about 20μm, which significantly improves the pattern fineness and preparation reliability of the conductive coating.

[0027] (3) The PEDOT / PSS conductive coating prepared by the present invention has excellent biocompatibility and immunocompatibility, and can improve the long-term performance of implantable bioelectronics. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The thicknesses of the PP, PPE, PPES1, PPESS2, and PPES3 coatings prepared in Example 1 and Comparative Example 1 under dry and wet conditions.

[0029] Figure 2 Water contact angles of PP, PPE, PPES1, PPESS2, and PPES3 coatings prepared in Example 1 and Comparative Example 1.

[0030] Figure 3 Surface modulus of PP, PPE, PPES1 and PPES3 coatings prepared in Example 1 and Comparative Example 1.

[0031] Figure 4 The electrical conductivity of the PP, PPES1, PPESS2, and PPES3 coatings prepared in Example 1 and Comparative Example 1 ( Figure 4 Changes in the conductivity of the coating with time of immersion in PBS solution ( Figure 4 Middle (B).

[0032] Figure 5 The change and quantitative statistics of the charge storage density of the coatings prepared in Example 1 and Comparative Example 1 after 10 minutes of ultrasound are shown. Figure 5 (A) is PP coating, Figure 5 Middle (B) is PPE coating, Figure 5 Middle (C) is PPES1 coating, Figure 5 Middle (D) is PPESS2 coating, Figure 5 Middle (E) is PPES3 coating, Figure 5 Middle (F) is the quantitative statistics of each coating.

[0033] Figure 6 The patterned coatings prepared by combining different types of masks with the parameters of PPES1 in Example 1 are: Figure 6 (A) is the pattern of the interdigitated electrode coating. Figure 6 The middle (B) shows the pattern of the butterfly pattern coating.

[0034] Figure 7 This is a statistical chart of the charge storage density of PP, PPE, and PPES1 coatings in Application Example 1 after 5000 cyclic voltammetry tests.

[0035] Figure 8 The results of 180° peel test of PP, PPE and PPES1 in Application Example 1 are as follows: Figure 8 (A) is a real picture of the sample during testing. Figure 8 (B) is a statistical graph of the shear strength of the samples.

[0036] Figure 9 This is the actual picture of PP, PPE, and PPES1 coatings in Application Example 1 after 10,000 bends ( Figure 9 (A)) and the statistical diagram of the charge storage density changes of each coating ( Figure 9 Middle (B).

[0037] Figure 10 This is the change in electrochemical impedance of the PP and PPES1 coatings in Application Example 1 after 3600 reciprocating insertions into agar-simulated brain tissue.

[0038] Figure 11 Schematic diagram of the dimensions of the EEG metal mask used in Application Example 2.

[0039] Figure 12 is the electrochemical impedance spectroscopy of each sample in Application Example 2 ( Figure 12 (A)) and the average power density of each sample ( Figure 12 Middle (B).

[0040] Figure 13 2 is a time-frequency analysis diagram of the recorded EEG signals of each sample in Application Example 2.

[0041] Figure 14 MASSON slices of each sample in Application Example 3 after 4 weeks of subcutaneous implantation in mice ( Figure 14Middle (A)) and collagen thickness statistics ( Figure 14 Middle (B). DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art will make modifications or equivalent substitutions based on understanding the technical solution of the present invention, without departing from the spirit and scope of the technical solution of the present invention, and all should be encompassed within the protection scope of the present invention.

[0043] The raw materials used in the following specific embodiments are all purchased from the market.

[0044] Example 1 Step 1: Place the PET substrate in a plasma machine for 5 minutes; Step 2: Dissolve 0.25 wt% polyethyleneimine (PEI) (molecular weight ~70,000), 1.25 wt% sulfobetaine methacrylate, 0.0125 wt% 3-methacryloyloxypropyltrimethoxysilane (TMSPMA), and 0.0125 wt% ammonium persulfate (APS) in 10 mL of ethanol-water solution (V:V = 1:1), recorded as solution component A; add DMSO solution (15% of the volume of the PEDOT / PSS solution) to the PEDOT / PSS solution (1.1 wt%), stir for 6 h, and then dilute with ethanol-water solvent (V:V = 1:1) to a solid content of 0.32 wt% as solution component B; Step 3: Components A and B were placed in separate microsyringes and connected to a dual-channel ultrasonic spray system. A microfluidic pump precisely controlled the flow rates of component A at 10, 20, and 30 μL / min, while the flow rate of component B was 60 μL / min. The two components were ultrasonically atomized and thoroughly mixed at the nozzle, and then deposited on a 3 cm × 3 cm PET substrate. The spray times were 19 minutes (component A flow rate of 10 μL / min), 13 minutes (component A flow rate of 20 μL / min), and 11 minutes (component A flow rate of 30 μL / min). The substrate was maintained at 65°C on a hot plate during the ultrasonic spraying process.

[0045] Step 4: After spraying, the sample was placed in a saturated humidity environment at 80°C for 2 h to eventually form a stable conductive coating, which was recorded as PPES1, PPESS2, and PPES3 respectively.

[0046] Example 2 Step 1: Place the TPU substrate in a plasma machine for 5 minutes; Step 2: Dissolve 0.5 wt% PEI (molecular weight ~70,000), 2.5 wt% sulfobetaine methacrylate, 0.0125 wt% 3-methacryloyloxypropyltrimethoxysilane (TMSPMA), and 0.025 wt% ammonium persulfate (APS) in 10 mL of ethanol-water solution (V:V = 1:1), which is recorded as solution component A; add DMSO solution (15% of the volume of the PEDOT / PSS solution) to the PEDOT / PSS solution (1.1 wt%), stir for 6 h, and then dilute with ethanol-water solvent (V:V = 1:1) to a solid content of 0.32 wt% as solution component B; Step 3: Components A and B were placed in separate microsyringes and connected to a dual-channel ultrasonic spray system. A microfluidic pump precisely controlled the flow rates of component A at 40 μL / min and component B at 40 μL / min, allowing the two components to be ultrasonically atomized and thoroughly mixed at the nozzle. The components were then deposited onto a 3 cm × 3 cm TPU substrate for 15 minutes. The substrate was maintained at 65°C on a hot plate during the ultrasonic spraying process.

[0047] Step 4: After spraying, the sample is placed in a saturated humidity environment at 80°C and heated for 2 hours to form a stable conductive coating.

[0048] Example 3 Step 1: Place the PET substrate in a plasma machine for 5 minutes; Step 2: Dissolve 0.25 wt% PEI (molecular weight ~25000), 1.25 wt% carboxybetaine methacrylate (CBMA), 0.026 wt% 3-methacryloyloxypropyltrimethoxysilane (TMSPMA), and 0.025 wt% ammonium persulfate (APS) in 10 mL of ethanol-water solution (V:V = 1:1), recorded as solution component A; add DMSO solution (15% of the volume of the PEDOT / PSS solution) to the PEDOT / PSS solution (1.1 wt%), stir for 6 h, and then dilute with ethanol-water solvent (V:V = 1:1) to a solid content of 0.32 wt% as solution component B; Step 3: Components A and B were placed in separate microsyringes and connected to a dual-channel ultrasonic spray system. A microfluidic pump precisely controlled the flow rates of component A at 0 μL / min and 10 μL / min, while the flow rate of component B was 60 μL / min. The two components were ultrasonically atomized and thoroughly mixed at the nozzle, and then deposited onto a 3 cm × 3 cm PET substrate covered with a 40 μm line width mask. During ultrasonic spraying, the substrate was maintained at 65°C on a hot plate. The two coatings were obtained for 26 minutes (flow rate 0 μL / min) and 19 minutes (flow rate 10 μL / min), respectively. The substrate was maintained at 65°C on a hot plate during ultrasonic spraying.

[0049] Step 4: After spraying, the sample is placed in a saturated humidity environment at 80°C and heated for 2 hours to form a stable conductive coating.

[0050] Comparative Example 1 Step 1: Place the PET substrate in a plasma machine for 5 minutes; Step 2: Dissolve 0.25 wt% polyethyleneimine (PEI) (molecular weight ~70,000), 0.0125 wt% 3-methacryloxypropyltrimethoxysilane (TMSPMA), and 0.0125 wt% ammonium persulfate (APS) in 10 mL of ethanol-water solution (V:V = 1:1) as solution component A; add 15% DMSO solution by volume of the PEDOT / PSS solution to the PEDOT / PSS solution (1.1 wt%), stir for 6 h, and then dilute with ethanol-water solvent (V:V = 1:1) to a solid content of 0.32 wt% as solution component B; Step 3: Components A and B were placed in separate microsyringes and connected to a dual-channel ultrasonic spray system. A microfluidic pump precisely controlled the flow rates of component A at 0 μL / min and 10 μL / min, and component B at 60 μL / min, allowing the two components to be ultrasonically atomized and thoroughly mixed at the nozzle. The two components were then deposited onto a 3 cm × 3 cm PET substrate for 26 minutes (component A flow rate of 0 μL / min) and 23 minutes (component A flow rate of 10 μL / min), respectively. The substrate was maintained at 65°C on a hot plate during the ultrasonic spraying process.

[0051] Step 4: After spraying, the sample was placed in a saturated humidity environment and heated at 80°C for 2 hours to finally form a conductive coating, which was recorded as PP and PPE (without poly(methacrylate sulfobetaine) (PSBMA), i.e., without anion-π interaction).

[0052] Performance Testing The thickness of the PP, PPE, PPES1, PPESS2 and PPES3 coatings prepared in Example 1 and Comparative Example 1 was tested under dry and wet conditions. Figure 1 As shown, the dry thickness was measured by SEM, and the wet thickness was photographed by a digital camera under a bright field microscope at 40 times the magnification. The results show that the prepared series of coatings have similar dry thicknesses, which proves that the quality of the deposited substances is similar, which facilitates the comparison between subsequent coatings. After the coatings were immersed in PBS solution for 24 hours, the measured wet thickness showed that both the PP and PPE groups had more significant swelling behavior, which is because the polyelectrolytes in the system are not balanced. Correspondingly, in the PPES1 group, the charge is basically balanced, so its swelling rate decreases, and with the increase of the zwitterionic components in the PPES2 and PPES3 groups, the swelling rate of the coating increases.

[0053] Figure 2 The water contact angles of the PP, PPE, PPES1, PPESS2, and PPES3 coatings prepared in Example 1 and Comparative Example 1. The results show that the introduction of the zwitterionic polymer significantly improves the hydrophilicity of the coating.

[0054] Figure 3 The surface moduli of the PP, PPE, PPES1, and PPES3 coatings prepared in Example 1 and Comparative Example 1 are shown. The moduli were measured by nanoindentation, and the results showed that the preferred PPES1 coating of the present invention had higher surface elasticity than the PP coating, which can be attributed to the phase separation between the polyelectrolytes.

[0055] Figure 4 (A) is the conductivity of the PP, PPES1, PPESS2, and PPES3 coatings prepared in Example 1 and Comparative Example 1, Figure 4 (B) shows the change in conductivity of each coating as a function of immersion time in PBS solution. The results show that although the PP coating has a higher initial conductivity, while the conductivity of PPES1 and other modified coatings is relatively low, the conductivity stability of the PP coating is poor. After 28 days, the coating completely falls off, making it impossible to measure the conductivity. The lower initial conductivity of coatings such as PPES1 than that of the PP coating can be attributed to the introduction of non-conductive components, which leads to a reduction in the mass proportion of conductive components. At the same time, the dedoping of PEDOT / PSS after the addition of polyelectrolyte PEI leads to a decrease in its conductivity. However, overall, the PPES1 coating achieves a balance between conductivity and stability.

[0056] Figure 5 The change and quantitative statistics of the charge storage density of the coatings prepared in Example 1 and Comparative Example 1 after 10 minutes of ultrasound are shown. Figure 5 (A) is PP coating, Figure 5Middle (B) is PPE coating, Figure 5 Middle (C) is PPES1 coating, Figure 5 Middle (D) is PPESS2 coating, Figure 5 Middle (E) is PPES3 coating, Figure 5 (F) shows the quantitative statistics of each coating. The experimental steps are as follows: the coatings were ultrasonicated in a PBS water bath for 10 minutes, then cut into 2×2 cm square samples. Cyclic voltammetry curves were measured using an electrochemical workstation, and the charge storage density was calculated to characterize the ultrasonic stability of these coatings.

[0057] As can be seen from the results, the traditional PP coating and the PPE coating without the anion-π interaction showed significant damage after 10 minutes of ultrasound, resulting in a significant decrease in their charge storage density. The PPES1, PPES2, and PPES3 coatings of the present invention showed significant ultrasound stability. However, considering the stability and conductivity, the PPES1 coating was used as the representative coating for subsequent testing.

[0058] Figure 6 The patterned coatings prepared by combining different types of masks with the parameters of PPES1 in Example 1 are: Figure 6 (A) is the pattern of the interdigitated electrode coating. Figure 6 The image (B) shows a butterfly pattern coating, indicating that the present invention can be used to prepare coatings with high-precision and complex patterns.

[0059] Application Example 1 Evaluation of the electrochemical and mechanical stability of representative PEDOT / PSS coatings In this application example, different methods were used to evaluate the mechanical stability and electrochemical stability of the coating prepared by the method proposed in the present invention.

[0060] 1. Coating selection The PP and PPE control coatings and PPES1 coatings were prepared using Comparative Example 1 and Example 1 for subsequent testing.

[0061] 2. Evaluation of electrochemical stability The prepared coating samples were cut into 2×2 cm square sheets as working electrodes. Subsequently, the samples were subjected to 5000 cyclic voltammetry tests using a three-electrode system with a platinum mesh as the counter electrode and a silver-silver chloride electrode as the reference electrode. The electrochemical stability of the coating was determined by comparing the initial and final charge storage densities.

[0062] The results are as follows Figure 7As shown in the figure, the charge storage density (CSC / CSC0) of the PP coating decreased significantly after 5000 cycles of cyclic voltammetry. At the same time, due to the lack of anion-π interaction, the stability of the PPE coating was improved compared to the PP coating, but its charge storage density decreased by more than 30% after 5000 cycles. The PPES1 group only decreased by about 20%, indicating that it has better electrochemical stability.

[0063] 3. Evaluation of mechanical stability The 180° peel test was used to characterize the adhesion between PP, PPE, and PPES1 coatings and substrates. The test procedure is as follows: A high-strength adhesive tape is applied to the surface of the coated sample, ensuring close contact and free of bubbles. The sample is then secured to the fixture of a universal testing machine. A tensile force is applied to the tape at a rate of 20 mm / min along a 180° angle to peel the coating. The test machine collects force data during the peel process to quantify the adhesion between the coating and the substrate.

[0064] Figure 8 The results of 180° peel test of PP, PPE and PPES1 in Application Example 1 are as follows: Figure 8 The middle and back (A) is a real picture of the sample during testing. Figure 8 Figure (B) shows the shear strength of the samples. The shear strength of the PP coating is approximately 5 kPa; the shear strength of the modified PPE coating improves to approximately 20 kPa. Furthermore, the introduction of anion-π interactions into the coating system significantly enhances the adhesion of the PPES1 coating to the substrate, achieving a shear strength nearly six times that of conventional conductive coatings. Notably, unlike the adhesive failure mode exhibited by the PP coating, the failure of the PPES1 coating does not stem from insufficient adhesion between the coating and the substrate, but rather from the coating's inherent mechanical strength being unable to withstand the stresses of the peeling process, representing a cohesive failure characteristic of the coating.

[0065] To further demonstrate the significant improvement in stability achieved by the coating preparation method proposed in this invention compared to conventional coatings, the prepared samples, PP, PPE, and PPES1, were placed on a crankshaft connecting rod completely immersed in deionized water and subjected to reciprocating motion to achieve repeated bending in a wet environment. After 10,000 bends, the coatings were subjected to cyclic voltammetry (CV) using an electrochemical workstation to obtain cyclic voltammetry curves. The charge storage density of the coatings before and after bending was compared to determine whether the coatings were damaged.

[0066] PP and PPES1 coatings are as follows after 10,000 bending cycles: Figure 9In (A), the statistics of the charge storage density change are as follows Figure 9 As shown in (B), after 10,000 bends, the PP coating prepared by conventional methods exhibited significant shedding and a significant decrease in charge storage density. The PPE coating group also suffered some damage. In contrast, the PPES1 coating group showed no significant damage and only a limited decrease in charge storage density.

[0067] In addition, the prepared PP and PPES1 coatings were repeatedly inserted into 0.6% agarose simulated brain tissue immersed in deionized water 3600 times using a crankshaft connecting rod. The electrochemical impedance spectroscopy of the coatings was then tested to confirm the damage to the coatings during the insertion process. Figure 10 As shown in the figure, after 3600 insertion cycles, the PP coating was significantly damaged, making it impossible to measure its electrochemical impedance. In contrast, the electrochemical impedance of the PPES1 coating did not increase significantly. These results indicate that the PPES1 coating has better mechanical stability.

[0068] Application Example 2 Representative PEDOT / PSS patterned coatings prepared brain electrodes are used for EEG signal monitoring and stability evaluation. In this application example, the stability difference between the brain electrodes prepared according to the method proposed in the present invention and the electrodes prepared by conventional spraying for EEG signal monitoring is evaluated.

[0069] 1. Electrode preparation and implantation In order to prepare brain electrodes with EEG signal recording performance, we customized Figure 11 The metal mask shown is covered on the PET substrate during the spraying process, and then the EXP electrode and CON electrode are prepared according to the parameters for preparing PPES1 in Example 1 and preparing PP in Comparative Example 1, respectively. The electrodes are then cut to a size suitable for implantation in the rat brain and encapsulated with silicone, leaving only the electrode contacts exposed.

[0070] The EXP electrodes and CON electrodes were divided into two groups. Ultrasound was performed on one group of EXP and CON electrodes. Since the CON electrodes could not withstand long-term ultrasound, they were only ultrasounded for 30 seconds, which was recorded as CON-SON. The EXP electrodes, however, had good stability and could withstand ultrasound for 10 minutes without obvious damage, which was recorded as EXP-SON.

[0071] The SD rats were then anesthetized, and after exposing the skull, a bone drill was used to drill holes in the target area for electrode implantation. Two stainless steel screws were then inserted parallel to the implantation site approximately 5 mm from the implantation site, serving as the counter electrode and reference electrode for the electrochemical impedance spectroscopy test. Finally, with the assistance of a stereotaxic apparatus, the electrodes were precisely implanted into the designated brain region.

[0072] 2. Data collection and analysis After electrode implantation, the electrochemical impedance of the electrodes was first measured using an electrochemical workstation (CHENHUA). Two stainless steel screws served as reference and counter electrodes, respectively. Subsequently, EEG signals were acquired using an electrophysiological recording system. After signal acquisition, the EEG data were processed using high-pass and low-pass filtering, and time-frequency plots were generated and power spectral density was calculated.

[0073] The electrochemical impedance spectroscopy results at 1 kHz are shown in Figure 2. Figure 12 As shown in (A), the CON and EXP electrodes without ultrasound treatment have similar impedance values. After ultrasound treatment, the impedance of the CON-SON electrode increased significantly, while the impedance of the EXP-SON electrode did not change significantly. Further analysis of the recorded EEG signals revealed that Figure 12 As shown in (B), the quality of the signals recorded by the EXP electrode and the EXP-SON electrode before and after ultrasonic treatment is basically the same, with only a slight decrease in power density.

[0074] like Figure 13 As shown in the figure, the signal quality recorded by the CON electrode after ultrasound treatment (CON-SON) significantly deteriorated, and the power density was greatly reduced, while the EXP electrode performed well. These results demonstrate that the EEG electrodes prepared by this invention have excellent electrochemical stability and signal recording performance, and can effectively record high-quality EEG signals even under external perturbation conditions.

[0075] Application Example 3: Representative PEDOT / PSS coatings used to improve material immunocompatibility and anti-foreign body reaction 1. Animal surgery process This application example describes the fibrotic response of a PEDOT / PSS-stabilized coating in a mouse subcutaneous implantation model. PP, PPE, and PPES1 coatings prepared in Example 1 and Comparative Example 1, along with a PET substrate, were implanted subcutaneously on the backs of C57BL / 6 female mice. Fibrotic response was evaluated on day 28.

[0076] 2. H&E and Masson trichrome staining immunohistochemical sections Mice were sacrificed at week 4, and the implants and surrounding tissues were excised, fixed with 10% formaldehyde, embedded in paraffin, and sectioned for hematoxylin and eosin (H&E) / Masson's trichrome staining and immunohistochemical staining. Images were acquired using a Nikon intensilight CHGFI microscope equipped with NIS-Elements AR software and an Olympus virtual slide microscope (VS120-S6-W). Collagen density was measured by calculating the percentage of blue pixel coverage at 50-μm intervals in Masson's trichrome-stained tissue images.

[0077] The MASSON sections of each sample 4 weeks after being implanted into the mouse subcutaneously are shown in the figure. Figure 14 Middle (A), collagen thickness statistics as shown Figure 14 As shown in (B), a dense collagen capsule was clearly formed in the tissue surrounding the PET, PP, and PPE samples. Notably, almost no fibrotic reaction was observed around the PPES1 sample, indicating its excellent ability to resist foreign body reactions.

Claims

1. A method for preparing a patterned PEDOT / PSS conductive coating that is stable in a wet environment, characterized in that: Including steps: Step 1, performing plasma or ozone activation treatment on the substrate; Step 2: dissolving the polycation, zwitterionic monomer, double bond silane and initiator to obtain solution component A, and diluting PEDOT / PSS to obtain solution component B; Step 3, depositing component A and component B on the surface of a substrate covered with a patterned mask through dual-channel ultrasonic atomization spraying to obtain a coating; Step 4: polymerizing the substrate containing the coating under saturated humidity to obtain the patterned PEDOT / PSS conductive coating.

2. The method for preparing a patterned PEDOT / PSS conductive coating that is stable in a wet environment according to claim 1, wherein: The polycation includes any one or more of chitosan, polyethyleneimine, polydimethyldiallylammonium chloride, polyallylamine hydrochloride, polylysine, polyquaternary ammonium salts and copolymers or derivatives thereof; And / or, the zwitterionic monomer includes one or more of sulfobetaine methacrylate, carboxybetaine methacrylate, and methacryloyloxyethyl phosphorylcholine; And / or, the double bond silane includes one or more of 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and allyltriethoxysilane; And / or, the initiator includes one or more of ammonium persulfate, potassium persulfate, azodimethylvaleronitrile dihydrochloride, and azodimethylpropyleneamine dihydrochloride.

3. The method for preparing a patterned PEDOT / PSS conductive coating stable in a wet environment according to claim 1, characterized in that: In the solution component A, the mass fraction of the polycationic component is 0.01-1% of the total solution mass, the mass fraction of the zwitterionic monomer is 0.5-3% of the total solution mass, the mass fraction of the double bond silane is 0.01-0.1% of the total solution mass, and the mass fraction of the initiator is 0.01-0.1% of the total solution mass; And / or, in the solution component B, the mass fraction of PEDOT / PSS is 0.1-0.5 wt %.

4. The method for preparing a patterned PEDOT / PSS conductive coating stable in a wet environment according to claim 1, characterized in that: The solvents of solution component A and solution component B include one or more of water and ethanol.

5. The method for preparing a patterned PEDOT / PSS conductive coating stable in a wet environment according to claim 1, characterized in that: In step 3, the flow rates of component A and component B are 5-100 μL / min respectively; the flow rate ratio of component A to component B is 1:1-10.

6. The method for preparing a patterned PEDOT / PSS conductive coating stable in a wet environment according to claim 1, characterized in that: In step 3, the substrate temperature during the spraying process is 50-70°C; And / or, the polymerization in step 4 is allowed to stand at saturated humidity of 70-90° C. for 1-4 hours.

7. The method for preparing a patterned PEDOT / PSS conductive coating stable in a wet environment according to claim 1, characterized in that: The substrate comprises any one of the following materials: (1) Metal materials: any one of stainless steel, titanium and its alloys, cobalt-based alloys, nickel-titanium alloys, magnesium and its alloys, zinc and its alloys, iron and its alloys; or, (2) Inorganic materials: any one of glass, silicon dioxide, titanium dioxide, carbon materials, silicon, and titanium nitride; or (3) Polymer materials: any of polyester, polyethylene, polypropylene, polytetrafluoroethylene, polyvinyl chloride, polystyrene and their copolymers or derivatives.

8. The method for preparing a patterned PEDOT / PSS conductive coating stable in a wet environment according to claim 1, characterized in that: In step 1, the plasma or ozone activation time is 1 to 60 minutes. 9 . A wet environment stable patterned PEDOT / PSS conductive coating prepared by the preparation method according to any one of claims 1 to 8 .

10. Use of the patterned PEDOT / PSS conductive coating according to claim 9 in preparing a bioelectrode.

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