A composite coating and method of making and use thereof

Abstract

This invention discloses a composite coating, its preparation method, and its application. The composite coating is prepared from a composite solution containing the following components by mass percentage: lubricating component: 3%~8%; nano zinc oxide: 1%~3%; double-chain quaternary ammonium salt: 0.2%~1%; dispersing agent: 0.02%~0.08%; water: balance; wherein the lubricating component is polyvinylpyrrolidone and / or polyethylene glycol. This invention overcomes the bottleneck of "difficulty in achieving both lubrication and antibacterial properties" in the prior art. By cleverly utilizing the "dual function" of double-chain quaternary ammonium salt under specific processes, monodispersion of inorganic nanoparticles in a polymer matrix is ​​achieved, ultimately constructing a ternary composite coating with both extremely low friction coefficient, rapid bactericidal effect, and long-lasting antibacterial ability.

Description

Technical Field

[0001] This invention relates to the field of coating materials technology, and in particular to a composite coating, its preparation method, and its application. Background Technology

[0002] Medical catheters (such as central venous catheters and urinary catheters) face two core material science challenges during insertion and indwelling: first, the high surface friction coefficient of the catheter substrate (such as silicone rubber and polyurethane) leads to mechanical damage to tissues; second, the foreign body surface is highly susceptible to bacterial adhesion and the formation of a difficult-to-eradicate biofilm, which in turn leads to catheter-related infections (CRI).

[0003] Currently, constructing hydrophilic lubricating coatings (such as polyvinylpyrrolidone PVP or hyaluronic acid) on the surface of catheters is a mature solution for reducing the coefficient of friction. However, simple hydrophilic coatings lack intrinsic antibacterial activity; the water-rich microenvironment formed after water absorption and swelling may actually facilitate early colonization by microorganisms. To address the infection problem, researchers have attempted to introduce antibacterial agents into the lubricating coating. Common strategies include: (1) Introducing antibiotics (such as minocycline): There is a serious risk of inducing bacterial resistance.

[0004] (2) Introducing inorganic nano-antibacterial agents (such as nano-silver and nano-zinc oxide): Although they have broad-spectrum antibacterial properties and are not prone to drug resistance, inorganic nanoparticles are prone to severe agglomeration in polymer solutions. This agglomeration not only weakens the antibacterial efficacy of the nanoparticles, but more fatally, the microscopic protrusions formed by the agglomerates on the coating surface will completely destroy the smoothness of the coating, leading to a sharp increase in the coefficient of friction, thereby losing the original lubrication function of the coating.

[0005] (3) Introduce small organic molecule antibacterial agents (such as quaternary ammonium salts): These antibacterial agents have a fast onset of action, but they are highly water-soluble and easily lose their properties in the body fluid environment, which cannot meet the long-term antibacterial requirements during catheter placement (usually more than 7-14 days).

[0006] Existing technologies, in attempting to balance "lubrication" and "antibacterial properties," have fallen into a technological paradox: If long-lasting inorganic nanoparticles are used, their aggregation will destroy lubricity; if small-molecule organic antibacterial agents are used, although they do not affect lubrication, they cannot achieve long-lasting protection. How to achieve both uniform dispersion of nanoparticles to ensure an ultra-slip surface and efficient antibacterial activity throughout the entire time period (immediate + long-lasting) in a coating system is a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes a composite coating that combines an extremely low coefficient of friction, rapid sterilization, and long-lasting antibacterial ability.

[0008] A second aspect of the present invention also provides a method for preparing a composite coating.

[0009] A third aspect of the present invention also provides a medical catheter.

[0010] A fourth aspect of the present invention also provides an application.

[0011] According to a first aspect of the present invention, a composite coating is provided, the composite coating being prepared from a composite solution comprising the following components in mass percentage: Lubricating components: 3%~8%; Nano zinc oxide: 1%~3%; Double-chain quaternary ammonium salts: 0.2%~1%; Dispersing agent: 0.02%~0.08%; Water: Balance; The lubricating components are polyvinylpyrrolidone and / or polyethylene glycol.

[0012] According to a preferred embodiment of the present invention, the double-chain quaternary ammonium salt is decyl dimethyl ammonium chloride or bis(dodecyl) dimethyl ammonium chloride.

[0013] According to a preferred embodiment of the present invention, the average particle size of the nano zinc oxide is 20 nm to 50 nm.

[0014] According to a preferred embodiment of the present invention, the dispersing agent is at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, or polysorbate nonionic surfactant.

[0015] According to a preferred embodiment of the present invention, the polyvinylpyrrolidone is designated as K30 and / or K90.

[0016] According to a preferred embodiment of the present invention, the number average molecular weight of the polyethylene glycol is 2000-6000 Daltons.

[0017] According to a preferred embodiment of the present invention, the method for preparing the composite solution includes the following steps: S1. Mix the lubricating component with water and stir to obtain mixture I; mix nano zinc oxide, water and dispersant, and sonicate at 0~10℃ to obtain mixture II; S2. Mix the double-chain quaternary ammonium salt and mixture I with stirring II, and then add mixture II dropwise to obtain the composite solution.

[0018] According to a preferred embodiment of the present invention, the frequency of the ultrasound is 35~45kHz.

[0019] According to a preferred embodiment of the present invention, the power of the ultrasound is 150~300W.

[0020] According to a preferred embodiment of the present invention, the rotational speeds of stirring I and stirring II are independently selected from 300 to 500 rpm.

[0021] According to a preferred embodiment of the present invention, the stirring time of step I is 1 to 2 hours.

[0022] According to a preferred embodiment of the present invention, the dripping rate is 1~3 mL / min.

[0023] The composite coating according to embodiments of the present invention has at least the following beneficial effects: This invention breaks through the bottleneck of "difficulty in achieving both lubrication and antibacterial properties" in the prior art. By cleverly utilizing the "dual function" of double-chain quaternary ammonium salts under specific processes (i.e., the biological function as an antibacterial agent and the physicochemical function as a surfactant), it achieves the monodispersion of inorganic nanoparticles in a polymer matrix, and finally constructs a ternary composite coating with extremely low friction coefficient, rapid sterilization and long-lasting antibacterial ability.

[0024] A method for preparing a composite coating as described in the first aspect of the present invention, provided by a second aspect of the present invention, comprises the following steps: The matrix is ​​immersed in the composite solution, and then separated and dried to obtain the final product.

[0025] According to a preferred embodiment of the present invention, the drying is a stepped drying film formation.

[0026] According to a preferred embodiment of the present invention, the stepped drying includes first drying at 25~40℃ for 30~60 min; and then drying at 60~70℃ for 1~2 h.

[0027] According to a preferred embodiment of the present invention, the separation method includes pulling the liquid surface at a constant speed.

[0028] A third aspect of the present invention provides a medical catheter comprising the composite coating described in the first aspect of the present invention.

[0029] The fourth aspect of this invention provides the application of the composite coating described in the first aspect of this invention in the preparation of a surface modification layer for medical devices.

[0030] According to a preferred embodiment of the present invention, the medical device includes a central venous catheter, a urinary catheter, or an interventional catheter; the substrate of the medical device is silicone rubber, polyurethane, or polyvinyl chloride.

[0031] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the preparation process in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the microstructure of the composite coating of the present invention. Detailed Implementation

[0033] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0034] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0035] In some embodiments of the present invention, a composite coating is provided, the coating being prepared from a composite solution comprising the following components by mass percentage: Lubricating components: 3%~8%; Nano zinc oxide: 1%~3%; Double-chain quaternary ammonium salts: 0.2%~1%; Dispersing agent: 0.02%~0.08%; Water: Balance; The lubricating components are polyvinylpyrrolidone and / or polyethylene glycol.

[0036] Understandably, this invention breaks through the bottleneck of "difficulty in achieving both lubrication and antibacterial properties" in the prior art. By cleverly utilizing the "dual functions" of double-chain quaternary ammonium salts under specific processes (i.e., the biological function as an antibacterial agent and the physicochemical function as a surfactant), it achieves monodispersion of inorganic nanoparticles in a polymer matrix, and finally constructs a ternary composite coating with extremely low friction coefficient, rapid sterilization and long-lasting antibacterial ability.

[0037] Understandably, in the initial stage, the double-chain quaternary ammonium salt rapidly disrupts the bacterial cell membrane through electrostatic adsorption, providing highly efficient and rapid initial bactericidal capabilities. This effectively compensates for the loss of Zn²⁺ due to PVP encapsulation in the initial hydration stage of ZnO nanoparticles.+ It releases a slow-release "antibacterial window period".

[0038] Later, as the surface quaternary ammonium salt is gradually consumed, the PVP coating swells moderately, and the internal nano-ZnO begins to continuously and stably release Zn²⁺ into the microenvironment. + Zn² + By interfering with bacterial transmembrane transport and enzyme metabolism, it takes over the task of long-term antibacterial action.

[0039] In addition, the composite coating of the present invention has excellent adhesion, and the coating system has good compatibility with ethylene oxide (EO) sterilization and will not cause polymer degradation that may occur with gamma-ray sterilization, which fully meets the actual application requirements of clinical medical devices.

[0040] In some embodiments of the present invention, the double-chain quaternary ammonium salt is decyl dimethyl ammonium chloride or bis(dodecyl) dimethyl ammonium chloride.

[0041] In some embodiments of the present invention, the average particle size of the nano zinc oxide is 20 nm to 50 nm.

[0042] In some embodiments of the present invention, the dispersing agent is at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, or polysorbate nonionic surfactants.

[0043] In some embodiments of the present invention, the polyvinylpyrrolidone is designated as K30 and / or K90.

[0044] In some embodiments of the present invention, the number-average molecular weight of the polyethylene glycol is 2000-6000 Daltons.

[0045] In some embodiments of the present invention, the method for preparing the composite solution includes the following steps: S1. Mix the lubricating component with water and stir to obtain mixture I; mix nano zinc oxide, water and dispersant, and sonicate at 0~10℃ to obtain mixture II; S2. Mix the double-chain quaternary ammonium salt and mixture I with stirring II, and then add mixture II dropwise to obtain the composite solution.

[0046] Understandably, through the specific "ordered mixing" process of this invention (first dissolving the quaternary ammonium salt in PVP, then slowly adding the ZnO dispersion), the double-chain quaternary ammonium salt, as a highly efficient cationic surfactant, undergoes hydrophobic association between its hydrophobic alkyl chains and PVP segments, while the positively charged quaternary ammonium groups are anchored to the periphery of the hydration layer on the ZnO particle surface through electrostatic or complexation interactions. This unique interfacial interaction not only provides strong steric hindrance, completely preventing the aggregation of ZnO particles during film formation, but also improves the flexibility of the PVP segments. The resulting coating is extremely dense and smooth, with the nanoparticles achieving true monodispersion, thus achieving an extremely low coefficient of friction.

[0047] Generally, those skilled in the art would assume that mixing cationic (quaternary ammonium salt) and anionic (SDBS / SDS) surfactants would produce precipitation. However, in the specific process of this invention, the amount of SDBS used is extremely low, and it is pre-adsorbed on the ZnO surface before mixing, significantly reducing the free concentration; in addition, the slow dropwise addition and kinetic control successfully avoid macroscopic precipitation, and instead form a stable mixed adsorption layer.

[0048] In some embodiments of the present invention, the frequency of the ultrasound is 35-45 kHz. For example, it includes 35 kHz, 36 kHz, 37 kHz, 38 kHz, 40 kHz, 45 kHz, 45 kHz, or any subrange consisting of two of the above values.

[0049] In some embodiments of the present invention, the power of the ultrasound is 150~300W. For example, it includes 150W, 160W, 180W, 200W, 220W, 250W, 260W, 280W, 300W, or any sub-range consisting of two of the above values.

[0050] In some embodiments of the present invention, the rotational speeds of stirring I and stirring II are independently selected from 300 to 500 rpm. For example, this includes 300 rpm, 320 rpm, 350 rpm, 380 rpm, 400 rpm, 420 rpm, 450 rpm, 480 rpm, 500 rpm, or any subrange consisting of two of the above values.

[0051] In some embodiments of the present invention, the stirring time is 1-2 hours.

[0052] In some embodiments of the present invention, the dripping rate is 1~3 mL / min.

[0053] In some embodiments of the present invention, a method for preparing a composite coating as described in the first aspect of the present invention is provided, comprising the following steps: The matrix is ​​immersed in the composite solution, and then separated and dried to obtain the final product.

[0054] In some embodiments of the present invention, the drying is a stepped drying film formation.

[0055] In some embodiments of the present invention, the stepped drying includes first drying at 25~40°C for 30~60 min; then drying at 60~70°C for 1~2 h.

[0056] In some embodiments of the present invention, the separation method includes pulling the liquid out of the liquid at a constant speed.

[0057] In some embodiments of the present invention, a medical catheter is provided, comprising the composite coating described in the first aspect of the present invention. Thus, the medical catheter of the present invention possesses all the technical effects of the composite coating of the present invention.

[0058] In some embodiments of the present invention, the application of the composite coating described in the first aspect of the present invention in the preparation of a surface modification layer for medical devices is provided.

[0059] In some embodiments of the present invention, the medical device includes a central venous catheter, a urinary catheter, or an interventional catheter; the substrate of the medical device is silicone rubber, polyurethane, or polyvinyl chloride.

[0060] Example 1 This example provides a composite coating and a medical catheter formed from the composite coating. The fabrication process flow diagram is shown below. Figure 1 As shown in the diagram, the microstructure of the prepared polyurethane conduit is as follows. Figure 2 As shown. The preparation method is as follows: The composite solution consists of the following components: PVP (K90, molecular weight approximately 360,000): 5%; nano ZnO (average particle size 30 nm): 2%; decyl dimethyl ammonium chloride (DDAC, purity ≥ 95%): 0.5%; sodium dodecylbenzenesulfonate (SDBS, analytical grade): 0.05%; and deionized water (resistivity ≥ 18 MΩ·cm): 92.45%.

[0061] (1) Add 5g PVP (K90) to 50g deionized water and stir magnetically at 400 rpm for 2 hours at 25℃ until completely dissolved to obtain a transparent solution with high viscosity (about 150 mPa·s).

[0062] (2) Add 2g of nano ZnO to 42.45g of deionized water and stir at 600 rpm for 2 hours for pre-dispersion; then add 0.05g of SDBS and continue stirring at 600 rpm for 1 hour; then place the mixture in a 5℃ ice water bath and ultrasonically disperse it at 40kHz and 200W for 45 minutes to obtain a milky white uniform dispersion.

[0063] (3) Add 0.5g of DDAC to the PVP solution in step (1) and stir for 20 minutes until completely dissolved; then, under continuous magnetic stirring at 400rpm, slowly add the ZnO dispersion in step (2) at a rate of 2 mL / min; after the addition is complete, continue magnetic stirring for 3 hours. During this process, no macroscopic precipitation was observed, and the system remained stable and homogeneous.

[0064] (4) Immerse the clean and dry polyurethane conduit vertically into the composite coating solution and hold for 20 seconds; then pull it out of the liquid at a constant speed of 2.0 mm / s. Due to the high molecular weight of PVP K90, the solution has a high viscosity. According to the Landau-Levich equation, a thick wet film can be obtained with a single dip coating.

[0065] (5) Place the pulled-out tubing in a hot air oven and slowly dry it at 35°C for 45 minutes to allow the PVP long chains to fully rearrange and physically entangle on the surface of the tubing; then raise the temperature to 65°C and continue drying for 1.5 hours to allow the moisture to evaporate completely. Finally, a dense composite coating with a thickness of about 10.2 μm is formed on the surface of the tubing. Ethylene oxide (EO) low-temperature sterilization is recommended.

[0066] Example 2 This example provides a composite coating and a medical catheter formed from the composite coating, as detailed below: The composite solution consists of the following components: 8% PVP (K90), 1% nano ZnO (average particle size 20nm), 0.2% didodecyl dimethyl ammonium chloride (DDAAC), 0.02% sodium dodecyl sulfate (SDS), and 90.78% deionized water.

[0067] The preparation method is basically the same as in Example 1, with the main difference being: in step (2), the ZnO dispersion is sonicated in an ice-water bath at 3°C ​​for 60 minutes; in step (3), the dropping rate is 1.5 mL / min and the mixture is stirred for 4 hours; in step (4), the immersion time is 10 seconds and the lifting speed is 1.0 mm / s; in step (5), the mixture is dried at 30°C for 60 minutes and then at 60°C for 2 hours. The final coating thickness is approximately 12.1 μm.

[0068] Example 3 This example provides a composite coating and a medical catheter formed from the composite coating, as detailed below: The composite solution consists of the following components: 4% PVP+PEG mixture (mass ratio 4:1) (of which PVP K90 is 3.2% and PEG4000 is 0.8%), 3% nano ZnO (average particle size 50nm), 1% DDAC, 0.08% SDBS, and 91.92% deionized water.

[0069] The preparation process is basically the same as in Example 1, with the main differences being: in step (1), PVP and PEG are dissolved together; in step (2), the mixture is sonicated in an ice-water bath at 8°C for 30 minutes; in step (3), the dropping rate is 3 mL / min and the mixture is stirred for 2 hours; in step (4), the mixture is immersed for 30 seconds and pulled up at a speed of 3.0 mm / s; and in step (5), the mixture is dried at 40°C for 30 minutes and then dried at 70°C for 1 hour. The final coating thickness is approximately 8.3 μm.

[0070] Comparative Example 1 This example provides a composite coating and a medical catheter formed from the composite coating. Other dosages and preparation methods are the same as in Example 1, except that the formulation is 5% PVP (K90) and 95% deionized water.

[0071] Comparative Example 2 This example provides a composite coating and a medical catheter formed from the composite coating. Other dosages and preparation methods are the same as in Example 1, except that nano zinc oxide is not added.

[0072] Comparative Example 3 This example provides a composite coating and a medical catheter formed from the composite coating. Other dosages and preparation methods are the same as in Example 1, except that no double-chain quaternary ammonium salt is added.

[0073] Comparative Example 4 This example provides an uncoated polyurethane catheter (Hunan Weier Medical Technology Co., Ltd.).

[0074] Performance testing The polyurethane conduits prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention were subjected to the following tests; the results are shown in Table 1.

[0075] (1) Friction coefficient test According to ASTM D1894 standard, the friction test was conducted using a friction tester under completely wetted physiological saline (0.9% NaCl). Test conditions: normal load 2N, sliding speed 50 mm / min, 100 cycles of reciprocating friction, and the average coefficient of kinetic friction was taken.

[0076] (2) Antibacterial rate test According to GB / T 31402-2023 standard, the antibacterial rates against *Escherichia coli* (ATCC 25922) and *Staphylococcus aureus* (ATCC 6538) were tested on day 1 and day 14 after coating preparation (during which the catheter was continuously immersed in PBS buffer at 37°C to simulate the in vivo environment). The initial bacterial concentration was 1×10⁻⁶. 5 ~ 5×10 5CFU / mL, co-culture time was 24 hours.

[0077] (3) Cytotoxicity test The MTT assay was used in accordance with ISO 10993-5. The coated catheters were extracted in DMEM medium at 37°C for 24 hours. The extract was then co-cultured with L929 mouse fibroblasts for 24 hours, and the relative cell viability was determined.

[0078] (4) Coating adhesion test Referring to ASTM D3359 (cross-cut tape peeling method), use a blade to cut a 1mm grid on the coating surface, apply 3M 610 standard tape, and then quickly peel it off. Observe and evaluate the coating peeling grade (5B is the best, no peeling, and 0B is the worst, >65% peeling).

[0079] Table 1

[0080] As can be seen from the data in Table 1, the friction coefficient of Comparative Example 1 (pure PVP) is 0.038. When 2% nano-ZnO is added (Comparative Example 3), the friction coefficient increases sharply to 0.068. This is consistent with the understanding of classical polymer physics: inorganic particles are prone to phase separation and agglomeration in polymer solutions, resulting in microscopic protrusions on the coating surface, which disrupts the continuity and smoothness of the hydration layer.

[0081] However, in Example 1, when 0.5% DDAC was introduced simultaneously, the coefficient of friction not only failed to maintain its high level of 0.068, but unexpectedly dropped to 0.032 (even lower than the 0.038 of pure PVP). This core data directly proves the underlying logic of the present invention: the double-chain quaternary ammonium salt plays a crucial role as a cationic surfactant in this system. Through a specific "ordered mixing" process, DDAC forms a stable steric hindrance layer on the surface of ZnO particles, completely suppressing particle agglomeration, allowing the coating to restore or even surpass its original extreme smoothness.

[0082] Furthermore, Comparative Example 2 (PVP+DDAC) exhibited an extremely high antibacterial rate (>99%) on day 1, but after 14 days of PBS immersion, the antibacterial rate plummeted to around 42.5%. This confirms the fatal flaw of water-soluble small-molecule quaternary ammonium salts being easily lost in bodily fluids.

[0083] Comparative Example 3 (PVP + ZnO) showed an antibacterial rate of only about 85% on day 1 (due to the ZnO being encapsulated by PVP, the initial Zn² content was lower). + (It releases extremely slowly, making it difficult to reach the sterilization threshold), but it can still maintain above 82% on the 14th day, demonstrating the long-lasting and sustained-release characteristics of inorganic nanomaterials.

[0084] Example 1 perfectly combines the advantages of both, achieving an antibacterial rate of >99.9% on day 1 (due to DDAC-led contact sterilization) and still exceeding 98.5% on day 14 (due to the sustained-release Zn²⁺). + (Relay antibacterial action).

[0085] Furthermore, the simple PVP coating (Comparative Example 1) is extremely prone to swelling and stickiness in an aqueous environment, with an adhesion level of only 2B, posing a risk of peeling off during clinical intubation. The adhesion of Example 1 jumps to 4B, the underlying mechanism of which is that monodisperse nano-ZnO particles (approximately 30nm) form a large number of nano-scale physical "anchors" (pinning effect) at the interface between the coating and the polyurethane substrate; at the same time, the step-drying process provides sufficient relaxation time for the high molecular weight PVP segments, enabling them to achieve deep physical entanglement at the interface.

[0086] The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A composite coating, characterized in that, The composite coating is prepared from a composite solution containing the following components by mass percentage: Lubricating components: 3%~8%; Nano zinc oxide: 1%~3%; Double-chain quaternary ammonium salts: 0.2%~1%; Dispersing agent: 0.02%~0.08%; Water: Balance; The lubricating components are polyvinylpyrrolidone and / or polyethylene glycol.

2. The composite coating according to claim 1, characterized in that, The double-chain quaternary ammonium salt is decyl dimethyl ammonium chloride or dodecyl dimethyl ammonium chloride.

3. The composite coating according to claim 1, characterized in that, The average particle size of the nano zinc oxide is 20nm~50nm.

4. The composite coating according to claim 1, characterized in that, The dispersing agent is at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, or polysorbate nonionic surfactants.

5. The composite coating according to claim 1, characterized in that, The number average molecular weight of the polyethylene glycol is 2000-6000 Daltons.

6. The composite coating according to claim 1, characterized in that, The preparation method of the composite solution includes the following steps: S1. Mix the lubricating component with water and stir to obtain mixture I; mix nano zinc oxide, water and dispersant, and sonicate at 0~10℃ to obtain mixture II; S2. Mix the double-chain quaternary ammonium salt and mixture I with stirring II, and then add mixture II dropwise to obtain the composite solution.

7. The composite coating according to claim 6, characterized in that, The frequency of the ultrasound is 35~45kHz.

8. A method for preparing the composite coating as described in any one of claims 1 to 7, characterized in that, Includes the following steps: The matrix is ​​immersed in the composite solution, and then separated and dried to obtain the final product.

9. A medical catheter, characterized in that, Includes the composite coating described in any one of claims 1 to 7.

10. The application of the composite coating as described in any one of claims 1 to 7 in the preparation of a surface modification layer for medical devices.

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