An artificial heart polymer leaflet composite and method of making the same

Abstract

This invention provides a polymer valve leaflet composite material for artificial hearts and its preparation method. The method involves first impregnating a fabric substrate with a first polymer to fill at least a portion of the interior with a first polymer. Then, a second polymer film is repeatedly coated onto one side of the fabric substrate. The fabric substrate is then flipped over and placed on a platform, and a third polymer film is repeatedly coated onto the other side of the substrate. This process ultimately yields a polymer valve leaflet composite material for artificial hearts with no obvious internal interface and excellent performance. In the above process, the impregnation method for preparing the first polymer film allows the solution to penetrate into the fabric, completely filling the gaps between the fibers and effectively avoiding defects such as voids within the material. During the subsequent coating process, by controlling the process parameters, the compatibility within the polymer layer is effectively enhanced, preventing the formation of an interface between the coating layer and the first polymer film, thus enhancing the overall stability of the material and preventing delamination between the substrate and the polymer coating during long-term use.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an artificial heart polymer valve leaflet composite material and its preparation method. Background Technology

[0002] Currently, the most mature artificial heart valves include mechanical valves and bioprosthetic valves. Mechanical valves are made of silicone rubber, metal, or pyrolytic carbon materials, offering high durability and fatigue resistance. However, patients must take anticoagulants for life after implantation, and there are risks such as thromboembolism, hemolysis, and infective endocarditis. Bioprosthetic valves are primarily made from pericardium extracted from the heart tissue of animals such as cattle and pigs. After chemical processing, they possess good mechanical properties and biocompatibility. Therefore, patients with bioprosthetic valves have a low incidence of thrombosis and do not require lifelong anticoagulation. However, due to the aging and calcification of biological tissue, bioprosthetic valves have poor durability, with an average lifespan of only 10 years. Furthermore, the directionality of the fibrous structure of the pericardial material cannot be controlled during growth, making it difficult to ensure the consistency of thickness and elasticity across different areas of the bioprosthetic valve. This results in subtle differences in stress during valve operation, exacerbating structural failure and functional degradation of the bioprosthetic valve.

[0003] Polymers are a novel type of valve material that possesses both good biocompatibility and durability, offering a longer lifespan than bioprosthetic valves while avoiding long-term anticoagulation therapy. Furthermore, the production and processing of polymer materials are simpler than that of pericardial valves, allowing for mass production and effectively reducing valve manufacturing costs. Existing valve materials typically consist of a base and a polymer coating material formed on the base surface. The base material serves as the primary load-bearing layer during valve use, while the coating material not only improves the overall performance of the valve material but also reduces the risk of rejection by the body during use.

[0004] Currently, valve materials are mainly prepared by impregnation and coating methods, where a coating material is applied to the substrate surface. However, due to the low compatibility between commonly used substrate materials (such as fabrics) and polymers, the bonding between the coating and the substrate is not tight, leading to defects such as voids within the composite material. During later use, the coating is prone to detaching from the substrate, resulting in reduced valve material strength, blood leakage from the valve, and even adverse effects on the human body. Furthermore, the coating thickness on both sides of the substrate material needs to be relatively uniform. Poor uniformity can cause thinner areas to become stress concentration points, which can also lead to coating detachment from the substrate during subsequent use, increasing the risk of valve failure.

[0005] In view of this, it is necessary to design an improved polymer valve composite material for artificial hearts and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide an artificial heart polymer valve leaflet composite material and its preparation method.

[0007] To achieve the above-mentioned objectives, the present invention provides a method for preparing a polymer valve leaflet composite material for an artificial heart, comprising the following steps:

[0008] S1. Immerse the plasma-treated fabric substrate in a first polymer solution so that the first polymer fills at least a portion of the fabric substrate; place the filled fabric substrate on the platform surface to make the surface of the filled fabric substrate flat.

[0009] S2. Then, the second polymer solution is coated on one side of the fabric substrate in n stages, and after drying and curing, a second polymer film is formed on one side of the fabric substrate. The second polymer film includes at least one polymer layer; wherein n≥2, and the concentration of the second polymer solution is greater than the concentration of the first polymer solution.

[0010] S3. After the fabric substrate has been treated in step S2, turn it over and place it on a platform with a wetting liquid and make the surface of the fabric substrate flat.

[0011] S4. Then, the third polymer solution is coated on the other side of the fabric substrate in k steps, and dried and cured to form a third polymer film on the other side of the fabric substrate. The third polymer film includes at least one polymer layer, thus obtaining the artificial heart polymer leaflet composite material. Wherein k≥2, the concentration of the third polymer solution is greater than the concentration of the first polymer solution, and the surface roughness Ra of the artificial heart polymer leaflet composite material is 50-1000nm.

[0012] Preferably, in step S1, the mass-volume concentration of the first polymer solution is 1-15 w / v%, and the solute is at least one selected from polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate; the solvent is at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide; and the viscosity of the first polymer solution is 100-1000 mPa·s.

[0013] Preferably, in step S1, the immersion time of the fabric substrate in the first polymer solution is 0.1-10 min.

[0014] Preferably, in step S2 or S4, each time the second polymer solution and / or the third polymer solution are coated, the mass-volume concentration is independently selected from 10-25 w / v%, and each time the solute of the second polymer solution and / or the third polymer solution is independently selected from at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate; the solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide; and each time the viscosity of the second polymer solution and / or the third polymer solution is independently selected from 500-3000 mPa·s.

[0015] Preferably, in step S2, the coating thickness of the second polymer solution is 50-1000 μm each time it is coated; in step S4, the coating thickness of the third polymer solution is 50-1000 μm each time it is coated.

[0016] Preferably, in step S3, the wetting liquid is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide.

[0017] Preferably, the drying and curing temperature is 40-80℃ and the time is 10-120 min.

[0018] On the other hand, the present invention also provides an artificial heart polymer leaflet composite material prepared by the above preparation method, comprising:

[0019] A fabric substrate, at least a portion of which is filled with a first polymer;

[0020] A second polymer film is formed on one side surface of the fabric substrate and is tightly bonded to the fabric substrate. The second polymer film includes at least one polymer layer and has a thickness of 5-100 μm.

[0021] A third polymer film is formed on the other side surface of the fabric substrate and is tightly bonded to the fabric substrate. The third polymer film includes at least one polymer layer and has a thickness of 5-100 μm. The surface roughness of the artificial heart polymer leaflet composite material is Ra = 50-1000 nm.

[0022] Preferably, the first polymer is at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate.

[0023] Preferably, the material of the second polymer film and / or the third polymer film is independently selected from at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate.

[0024] The beneficial effects of this invention are:

[0025] The method for preparing the artificial heart polymer valve composite material provided by the present invention involves first plasma treating a fabric substrate, then filling at least a portion of the fabric substrate with a first polymer by impregnation, then repeatedly preparing a second polymer film on one side of the fabric substrate by coating, then flipping the substrate over and placing it flat on a platform with a wetting liquid, and repeatedly preparing a third polymer film on the other side of the fabric substrate by coating, ultimately obtaining an artificial heart polymer valve composite material with good uniformity of polymer film thickness on both sides, no obvious internal interface, and excellent performance. In the above process, the fabric substrate is treated with plasma and then filled with the first polymer through impregnation. The process of the solution penetrating into the fabric fully fills the gaps between the fibers, effectively eliminating defects such as voids inside the composite material, enhancing the compatibility between the fabric substrate and the polymer coating, and improving the bonding force between the two. The coating and the substrate are tightly bonded, resulting in high strength of the composite material. Secondly, the adsorption effect of the wetting liquid ensures that the fabric substrate is placed completely flat on the platform, which is beneficial to improving the flatness of the subsequent third polymer film. In the subsequent coating process, by controlling the process parameters (coating thickness) and the properties (concentration, viscosity, solute type, etc.) of the second and third polymer solutions, multiple coatings are performed. This not only allows for convenient control of the thickness of the second and third polymer films, ensuring uniform coating, but also effectively enhances the compatibility within the polymer layers, avoids the appearance of interfaces between coating layers, enhances the overall stability of the material, and prevents delamination between the substrate and the polymer coating during long-term use of the composite material. Attached Figure Description

[0026] Figure 1 Here is a surface SEM image of the composite material obtained in Example 1 of this invention;

[0027] Figure 2 This is a cross-sectional SEM image of the composite material obtained in Example 1 of the present invention;

[0028] Figure 3 This is a cross-sectional SEM image of the composite material obtained in Example 2 of the present invention;

[0029] Figure 4 This is a cross-sectional SEM image of the composite material obtained in Example 3 of the present invention;

[0030] Figure 5This is a cross-sectional SEM image of the composite material obtained in Example 4 of the present invention;

[0031] Figure 6 This is a cross-sectional SEM image of the composite material obtained in Comparative Example 1 of this invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0034] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0035] This invention provides a polymer valve leaflet composite material for artificial hearts, comprising:

[0036] Fabric base;

[0037] A first polymer, which fills at least a portion of the interior of the fabric substrate;

[0038] A second polymer film is formed on one side of a fabric substrate and is tightly bonded to the fabric substrate. The second polymer film includes at least one polymer layer and has a thickness of 5-100 μm.

[0039] A third polymer film is formed on the other side of the fabric substrate and is tightly bonded to the fabric substrate. The third polymer film includes at least one polymer layer and has a thickness of 5-100 μm.

[0040] The surface roughness of the polymer valve composite material for artificial hearts is Ra = 50-1000 nm.

[0041] Furthermore, the present invention also provides a method for preparing the above-mentioned artificial heart polymer valve leaflet composite material, specifically including the following steps:

[0042] The plasma-treated fabric substrate is immersed in a first polymer solution so that the first polymer fills at least a portion of the fabric substrate; the filled fabric substrate is placed on the platform surface so that the surface of the filled fabric substrate is flat.

[0043] The second polymer solution is coated onto one side of the fabric substrate in n stages, and then dried and cured to form a second polymer film on one side of the fabric substrate. The second polymer film includes at least one polymer layer. Where n≥2, the concentration of the second polymer solution is greater than the concentration of the first polymer solution. By coating in multiple stages, the defect of easy collapse after a single coating when the solution concentration is high can be overcome, and the coating can be made more uniform and the thickness is easier to control. In addition, if the same second polymer solution is selected for each coating, the second polymer film contains only one polymer layer. If different second polymer solutions are selected, the second polymer film contains multiple polymer layers.

[0044] After the above treatment, the fabric substrate is turned over and placed on a platform with a wetting liquid, and the surface of the fabric substrate is made flat.

[0045] Then, the third polymer solution is coated k times on the other side of the fabric substrate, and dried and cured to form a third polymer film on the other side of the fabric substrate. The third polymer film includes at least one polymer layer, thus obtaining the artificial heart polymer valve composite material. Where k≥2, the concentration of the third polymer solution is greater than the concentration of the first polymer solution. In addition, during each coating process, if the same third polymer solution is selected, the third polymer film contains only one polymer layer; if different third polymer solutions are selected, the third polymer film contains multiple polymer layers.

[0046] In the above process, by controlling the concentration of the third polymer solution and the second polymer solution to be greater than that of the first polymer solution, the second polymer film and the third polymer film can be better formed on the fabric surface. If the concentration is too low, defects are likely to occur after forming, and the surface is likely to be uneven.

[0047] In one embodiment of the present invention, the material of the fabric substrate is one or more of ultra-high molecular weight polyethylene, polypropylene, polytetrafluoroethylene, polyacrylonitrile, polyethylene terephthalate, polyvinyl acetal, polyamide, and polyurethane; the weaving structure of the fabric substrate includes plain weave, twill weave, or perforated structure, and the weaving method includes machine weaving, knitting, or electrospinning. The fabric substrate serves as the internal support structure of the composite material and is used to bear the main stress of the valve.

[0048] In one embodiment of the present invention, the first polymer solution has a mass-volume concentration of 1-15 w / v% and a viscosity of 100-1000 mPa·s. The solute is at least one selected from polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate; the solvent is at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide. The fabric substrate is immersed in the first polymer solution for 0.1-10 min. After coating with the first polymer solution, it needs to be dried at a temperature of 40-80°C for 10-120 min. In the above process, by plasma-treating the fabric substrate and then controlling the immersion time in the solution within a certain range, it is ensured that the solution fully penetrates into the fabric and fills the pores between the fibers, avoiding defects such as voids within the composite material and effectively enhancing the bonding strength between the fabric and the polymer.

[0049] In one embodiment of the present invention, the mass-volume concentration of the second polymer solution and / or the third polymer solution is independently selected from 10-25 w / v%; the viscosity of the second polymer solution and / or the third polymer solution is independently selected from 500-3000 mPa·s; the solute of the second polymer solution and / or the third polymer solution is independently selected from at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate; the solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide; and the coating thickness of the second polymer solution and / or the third polymer solution is independently selected from 50-1000 μm. In the above technical solution, plasma treatment of the fabric substrate followed by controlling the immersion time of the substrate in the solution within a certain range ensures that the solution fully penetrates into the fabric, effectively enhancing the bonding strength and compatibility between the fabric substrate and the second and third polymer films. This ensures that the resulting composite material has no obvious voids, defects, or interfaces, improving the overall consistency of the material and preventing delamination during long-term use. By adjusting the coating thickness of the second and third polymer solutions, the thickness of the polymer film can be precisely controlled.

[0050] In one embodiment of the present invention, the wetting liquid is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide. It is used to impregnate the fabric substrate. The impregnation process can completely remove the air between the fibers inside the fabric and completely fill the pores between the fibers with the solution. Secondly, the wetting liquid can also dissolve part of the outer coating again, reduce its roughness, and achieve a surface shaping effect. Furthermore, the surface adsorption of the liquid can make the fabric completely flat on the substrate surface, ensuring that the thickness of the subsequent coating is uniform.

[0051] In one embodiment of the present invention, the fabric substrate is obtained by plasma treatment of a fabric to activate the fabric surface and improve the bonding force between the fabric and the polymer layer. The fiber material is composed of one or more combinations of ultra-high molecular weight polyethylene, polypropylene, polytetrafluoroethylene, polyacrylonitrile, polyethylene terephthalate, polyvinyl acetal, polyamide, and polyurethane. The weaving structure includes plain weave, twill weave, or openwork structure. The weaving method includes machine weaving, knitting, or electrospinning. The plasma treatment is carried out in an inert gas atmosphere, wherein the inert gas is one of nitrogen, argon, or helium, and the treatment time is preferably 400 s.

[0052] In the above technical solution, plasma treatment of the fabric substrate activates the fabric surface, which enhances the bonding strength between the fabric and the polymer film, prevents the substrate and coating from separating during long-term cyclic use of the composite material, avoids delamination failure of the composite material during cyclic use, and reduces the risk of fatigue failure.

[0053] In one embodiment of the present invention, the drying and curing temperature is 40-80℃ and the time is 10-120min. During the drying and curing process, the coating solution can be cured to ensure that there is no residual solvent in the composite material.

[0054] It should be noted that the substrate in this technical solution is only for the purpose of facilitating the coating operation. It can be any completely horizontal, clean, and defect-free plane, such as a metal plate, glass plate, or alloy plate, as long as the coating operation can be carried out smoothly. In actual operation, it can be selected as needed, and is not limited to this.

[0055] The following specific embodiments further illustrate the artificial heart polymer valve leaflet composite material and its preparation method proposed in this invention:

[0056] Example 1

[0057] This embodiment prepares an artificial heart polymer valve leaflet composite material. The specific preparation method includes the following steps:

[0058] The fabric is placed in a low-temperature vacuum plasma device and treated in nitrogen gas for 400 seconds to obtain a fabric base; the fabric is a PET / PE blend with a yarn fineness of 10 Dtex, a warp and weft density of 380 / 180 threads / inch, and a plain weave structure.

[0059] The fabric substrate is immersed in a 5 w / v% polyurethane / N,N dimethylacetamide solution for 1 min, then removed and flattened on the workbench surface, and dried and cured at 60°C for 50 min, filling at least a portion of the fabric substrate with the first polymer.

[0060] A second polymer film was prepared on the surface of a fabric substrate using a coating method. The specific steps are as follows: the distance between the coating device and the fabric substrate was set to 400 μm, and a 5 w / v% polyurethane / N,N dimethylacetamide solution was coated onto the fabric substrate. The temperature of the heating curing device was set to 60℃ and the curing time was set to 50 min. The second polymer film was prepared on the surface of the fabric substrate by coating n1 = 2 times.

[0061] Add 1 mL of N,N-dimethylacetamide to the workbench surface. After peeling the fabric with the second polymer film on the surface off the platform, place it flat on the platform where N,N-dimethylacetamide was dropped. Use N,N-dimethylacetamide to expel air bubbles between the fabric and the platform to ensure that the fabric substrate is completely flat.

[0062] The distance between the coating device and the first polymer film on the other side of the fabric is set to 200 μm. A 5 w / v% polyurethane / N,N-dimethylacetamide solution is coated onto the fabric substrate. After coating, the temperature of the heating curing device is set to 60°C and the heating time is 50 min for curing and drying. A third polymer film can be prepared on the surface of the fabric substrate by coating k1=2 times. After completion, the composite material is peeled off from the platform. It should be noted that the coating device and heating curing device involved in this embodiment are common structures in the art, so their structures are not described in detail here, as long as they achieve the corresponding purpose.

[0063] The surface SEM image of the composite material obtained in this embodiment is shown below. Figure 1 As shown in the figure, the composite material surface is uniform and the coating is dense; the cross-sectional view is as follows. Figure 2 As shown in the figure, the fabric substrate and the polymer coating are well bonded together. The coating completely penetrates into the fiber gaps of the fabric, and there is no obvious interface between the two. Furthermore, there is no obvious interface inside the polymer coating, indicating that the layers within the polymer coating are well bonded together.

[0064] Example 2

[0065] The only difference between Example 2 and Example 1 is that the second polymer film is coated 3 times (n2 = 3 times) and the third polymer film is coated 3 times (k2 = 3 times). All other preparation conditions are the same as in Example 1 and will not be repeated here. The cross-sectional SEM image of the composite material obtained in this example is shown below. Figure 3 As shown in the figure, the fabric substrate and the polymer coating are well bonded together, with no obvious interface between them. Furthermore, there is no obvious interface within the polymer coating, indicating that the layers within the polymer coating are well bonded together.

[0066] Example 3

[0067] The only difference between Example 3 and Example 1 is that the second polymer film coating number n3 = 4 times and the third polymer film coating number k3 = 4 times. Other preparation conditions are the same as in Example 1 and will not be repeated here. The cross-sectional SEM image of the composite material obtained in this example is shown below. Figure 4 As shown in the figure, the fabric substrate and the polymer coating are well bonded together, with no obvious interface between them. Furthermore, there is no obvious interface within the polymer coating, indicating that the layers within the polymer coating are well bonded together.

[0068] Example 4

[0069] Example 4 differs from Example 1 only in that: the yarn fineness of the fabric substrate is 20 Dtex, and the warp and weft density is 220 / 150 threads / inch; the number of coatings for the second polymer film is n4 = 4; the number of coatings for the third polymer film is k4 = 4. Other preparation conditions are the same as in Example 1 and will not be repeated here. The cross-sectional SEM image of the composite material obtained in this example is shown below. Figure 5 As shown in the figure, even after the yarn fineness and warp and weft density of the fabric substrate are changed, the prepared composite material fabric substrate and the polymer coating are still well bonded together, and there is no obvious interface between the two, indicating that the present invention can be adapted to a variety of fabric substrate materials.

[0070] Comparative Example 1

[0071] The only difference between Comparative Example 1 and Example 1 is that the concentration of the first polymer solution was changed from 5 w / v% to 0 w / v%, i.e., N,N-dimethylacetamide solvent. All other preparation conditions were the same as in Example 1 and will not be repeated here. The cross-sectional SEM image of the composite material obtained in this comparative example is shown below. Figure 6 As shown in the figure, the bonding between the fabric substrate and the polymer coating is poor, with obvious gaps and defects between them, which indirectly illustrates that the first polymer solution in Example 1 has the function of filling the fabric substrate.

[0072] The thicknesses of the composite materials and coating structures obtained in Examples 1 to 4 are shown in Table 1. It should be noted that the thickness of the composite material in the table is the sum of the thicknesses of the fabric and the polymer film (first polymer film + second polymer film + third polymer film), the upper coating is the thickness of the polymer film on one side of the fabric, and the lower coating is the thickness of the polymer film on the other side of the fabric.

[0073] Table 1. Thickness of composite materials and coating structures obtained in Examples 1 to 4

[0074] project Composite material thickness (μm) Top coating thickness (μm) Lower coating structure thickness (μm) Example 1 88 22 24 Example 2 105 31 29 Example 3 117 41 38 Example 4 161 46 45

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a polymer valve leaflet composite material for an artificial heart, characterized in that, Includes the following steps: S1. Immerse the plasma-treated fabric substrate in a first polymer solution so that the first polymer fills at least a portion of the fabric substrate; place the filled fabric substrate on the platform surface to make the surface of the filled fabric substrate flat. S2. Then, the second polymer solution is coated on one side of the fabric substrate in n stages, and after drying and curing, a second polymer film is formed on one side of the fabric substrate. The second polymer film includes at least one polymer layer; wherein n≥2, and the concentration of the second polymer solution is greater than the concentration of the first polymer solution. S3. After the fabric substrate has been treated in step S2, turn it over and place it on a platform with a wetting liquid and make the surface of the fabric substrate flat. S4. Then, the third polymer solution is coated on the other side of the fabric substrate in k steps, and dried and cured to form a third polymer film on the other side of the fabric substrate. The third polymer film includes at least one polymer layer, thus obtaining the artificial heart polymer leaflet composite material. Wherein k≥2, the concentration of the third polymer solution is greater than the concentration of the first polymer solution, and the surface roughness Ra of the artificial heart polymer leaflet composite material is 50-1000nm.

2. The preparation method according to claim 1, characterized in that, In step S1, the mass-volume concentration of the first polymer solution is 1-15 w / v%, and the solute is at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate; the solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide; and the viscosity of the first polymer solution is 100-1000 mPa·s.

3. The preparation method according to claim 1 or 2, characterized in that, In step S1, the fabric substrate is immersed in the first polymer solution for 0.1-10 minutes.

4. The preparation method according to claim 1, characterized in that, In step S2 or S4, each time the coating is applied, the mass-volume concentration of the second polymer solution and / or the third polymer solution is independently selected from 10-25 w / v%, and each time the coating is applied, the solute of the second polymer solution and / or the third polymer solution is independently selected from at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate; the solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide; and each time the coating is applied, the viscosity of the second polymer solution and / or the third polymer solution is independently selected from 500-3000 mPa·s.

5. The preparation method according to claim 1 or 4, characterized in that, In step S2, the coating thickness of the second polymer solution is 50-1000 μm each time it is coated; in step S4, the coating thickness of the third polymer solution is 50-1000 μm each time it is coated.

6. The preparation method according to claim 1, characterized in that, In step S3, the wetting liquid is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, acetone, dioxane, and dimethyl sulfoxide.

7. The preparation method according to claim 1, characterized in that, The drying and curing temperature is 40-80℃, and the time is 10-120 minutes.

8. A polymer leaflet composite material for an artificial heart, characterized in that, include: A fabric substrate, at least a portion of which is filled with a first polymer; A second polymer film is formed on one side surface of the fabric substrate and is tightly bonded to the fabric substrate. The second polymer film includes at least one polymer layer and has a thickness of 5-100 μm. A third polymer film is formed on the other side surface of the fabric substrate and is tightly bonded to the fabric substrate. The third polymer film includes at least one polymer layer and has a thickness of 5-100 μm. The surface roughness of the polymer valve composite material for artificial hearts is Ra = 50-1000 nm.

9. The composite material according to claim 8, characterized in that, The first polymer is at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate.

10. The composite material according to claim 9, characterized in that, The material of the second polymer film and / or the third polymer film is independently selected from at least one of polyurethane, polyamide, silicone, polysiloxane-polyurethane copolymer, styrene / isobutylene copolymer, polyisobutylene, and polyethylene-copolymer-polyvinyl acetate.

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