CN110124115B

CN110124115B - Hydrophobic coating, preparation method and application thereof, and absorbable implantable device

Info

Publication number: CN110124115B
Application number: CN201910288635.9A
Authority: CN
Inventors: 丁建东; 齐永丽; 李昕; 何垚; 李佩泽
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2019-04-11
Filing date: 2019-04-11
Publication date: 2021-04-02
Anticipated expiration: 2039-04-11
Also published as: CN110124115A

Abstract

The invention relates to a hydrophobic coating, a preparation method and application thereof, and an absorbable implantable device. When the hydrophobic coating provided by the invention covers the surface of the degradable material, the hydrophobic block can enable the hydrophobic coating to play a good water-resisting role in the early stage, so that the degradable material is hardly degraded; in the later stage, the degradable blocks are degraded, so that the porosity of the hydrophobic coating is improved, body fluid can contact with the degradable matrix material through the pores of the hydrophobic coating, and the degradation of the matrix material is promoted.

Description

Hydrophobic coating, preparation method and application thereof, and absorbable implantable device

Technical Field

The invention belongs to the technical field of degradable materials, and particularly relates to a hydrophobic coating, a preparation method and application thereof, and an absorbable implantable device.

Background

In the medical field, the degradable material can be degraded and absorbed by organisms after the in vivo service is finished, and can avoid the negative effects caused by the taking out of a secondary operation and the long-term existence of the material, so that the degradable material is widely used in the fields of orthopedics internal fixation, drug sustained and controlled release carriers, tissue engineering scaffolds, cardiovascular scaffolds and the like.

The degradation rate and mechanical properties of degradable materials are two important properties that are of interest for clinical applications. Ideal implantable devices (e.g., degradable vascular stents, resorbable bone plates, bone screws, etc.) typically require good mechanical support for a period of time early in implantation, and then are degraded and resorbed. Therefore, achieving a good match between the degradation rate and mechanical properties of the degradable material and the time required for repair of the implant site is a key issue to be solved in developing new implantable devices.

At present, the degradable materials applied to the absorbable implantable device substrate mainly include degradable polymers (such as polylactic acid, poly (lactic-co-glycolic acid), polycaprolactone, and the like) and corrodible metals (such as magnesium and magnesium alloy, iron and iron alloy, zinc and zinc alloy, and the like). The mechanical property of the degradable polymer is generally poor, when the degradable polymer is used for a degradable stent, enough mechanical supporting effect needs to be realized, the thickness of an instrument needs to be increased as cost, the application range of the instrument is limited to a certain extent, and meanwhile, the risks such as slow endothelial climbing and the like can be caused. For example, in order to realize the mechanical supporting effect of the coronary stent on blood vessels in the early stage, the thickness of the stent rod of the polylactic acid coronary stent of yapei corporation reaches 156 μm, which limits the application of the polylactic acid coronary stent in the field of small blood vessels. The corrodible metal has better mechanical property compared with degradable polymer, but the corrosion speed of metals or alloys such as magnesium, zinc and the like is high, so that the requirement of mechanical support is difficult to meet at the early stage of implantation.

Patent CN 105327397 a discloses a preparation method of a mesoporous calcium silicate coating degradable implant material on the surface of a medical magnesium alloy, which compounds a mesoporous calcium silicate coating material on the surface of a magnesium alloy, so as to prevent the magnesium alloy from contacting with corrosive media, improve the problem of too fast corrosion of the magnesium alloy, and control the degradation rate of the magnesium alloy in organisms.

The patent CN 107789665A discloses a preparation method of a magnesium alloy surface super-hydrophobic hydroxyapatite film layer, which is characterized in that a hydrothermal method is adopted to prepare a rod-shaped hydroxyapatite crystal layer with the length of micron scale and the diameter of nanometer scale on the magnesium alloy surface, then a stearic acid film is prepared on the surface of the hydroxyapatite film layer with the nanometer structure, a hydrophobic film layer with the contact angle of 153 degrees under static liquid drops is formed, the film layer can reduce the corrosion current density of the magnesium alloy by 2 orders of magnitude, the coating impedance modulus value is increased from 2029 omega-cm 2 to 117674 omega-cm 2, and the corrosion of the magnesium alloy is delayed.

The patent CN105420789A discloses a hydrophobic composite bioactive coating on the surface of pure magnesium or magnesium alloy and a preparation method thereof, wherein a micro-arc oxidation coating, an electro-deposition hydroxyapatite coating and a magnesium alloy substrate material are combined to prepare the composite bioactive coating, and the composite bioactive coating has the advantages of high compactness, good biocompatibility and good bone induction capability.

However, most of the existing published patents adopt coatings prepared based on inorganic materials to reduce the degradation rate of degradable matrix materials, and the inorganic material coatings are often brittle, so that the coatings are only suitable for orthopedic implants and are difficult to use in degradable cardiovascular stents, cerebrovascular stents and the like with high requirements on the toughness of the coatings; in addition, the inorganic material coating in the published patent has special requirements on the preparation process and the base material, and is limited to the treatment of magnesium and magnesium alloy materials. The cross-linked hydrophobic coating has better obdurability and can be used for a plurality of instruments such as cardiovascular and cerebrovascular stents, orthopedic implants and the like; the hydrophobic cross-linked coating has universality, and can be coated on the surfaces of various degradable base materials by a common coating preparation method to regulate and control the degradation rate of the degradable base materials.

Disclosure of Invention

The invention aims to solve the problems and provide a hydrophobic coating, a preparation method and application thereof and an absorbable implantable device.

The purpose of the invention is realized by the following technical scheme:

the hydrophobic coating is formed by crosslinking a hydrophobic monomer or a crosslinked coating formed by blending the hydrophobic monomer and a non-degradable component, wherein the hydrophobic monomer is a block copolymer comprising a hydrophobic block, a degradable block and a crosslinking functional group.

Preferably, the hydrophobic block is formed by a hydrophobic polymer, the degradable block is formed by a degradable polymer, the hydrophobic polymer and the degradable polymer are subjected to polymerization reaction to form the hydrophobic block and the degradable block which are connected through chemical bonds, and the crosslinking functional group is connected with the hydrophobic block and/or the degradable block through the chemical bonds to promote crosslinking between hydrophobic monomers to form the hydrophobic coating.

Preferably, the hydrophobic block is formed from at least one of polydimethylsiloxane, perfluoropolyether, polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, or polyvinylidene fluoride-hexafluoropropylene copolymer.

Preferably, the degradable blocks are formed from degradable polymers selected from at least one of polyglycolide, polyglycolic acid, poly-L-lactide, poly-D, L-lactide, polyhydroxybutyrate, poly-epsilon-caprolactone, poly-epsilon-alkyl substituted caprolactone, poly-delta-valerolactone, poly-beta-hydroxybutyrate, polycarbonate or polyether ester;

or the degradable polymer is a copolymer formed by at least two of monomers forming polyglycolide, polyglycolic acid, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly epsilon-caprolactone, poly epsilon-alkyl substituted caprolactone, poly delta-valerolactone, poly beta-hydroxybutyrate, polycarbonate or polyether ester.

Preferably, the molecular weight of the degradable block is 500-20000, and the polymerization degree of the degradable block is 20-40.

Preferably, the crosslinking functional group is selected from at least one of allyl, acryl, methacryl, epoxy, oxazoline, cyano, silicon hydroxyl or silicon alkoxy.

Preferably, the non-degradable component is selected from at least one of silicone rubber, polysiloxane, polysilazane, or a fluoropolymer. Preferably, the thickness of the hydrophobic coating is 0.01-100 μm, and more preferably 1-20 μm.

A method of preparing a hydrophobic coating comprising:

providing a hydrophobic monomer, and applying triggering conditions to the hydrophobic monomer to enable the hydrophobic monomer to be crosslinked to form the hydrophobic coating;

alternatively, a mixture of a hydrophobic monomer and a non-degradable component is provided, and conditions are applied to the mixture of the hydrophobic monomer and the non-degradable component to cause crosslinking of the non-degradable component or to cause crosslinking between the hydrophobic monomer and the non-degradable component to form the hydrophobic coating.

The initiation condition is ultraviolet irradiation, heat treatment or moisture action.

The ultraviolet light irradiation includes: mixing the hydrophobic monomer with a photoinitiator, and irradiating for 30 min-2 h by using 365nm ultraviolet light; the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-acetone, and the mass of the photoinitiator is 1 per mill of that of the hydrophobic monomer.

The heat treatment comprises the following steps: treating the hydrophobic monomer or the mixture of the hydrophobic monomer and the non-degradable component at 20-150 ℃ for 30 min-72 h;

the moisture effects include: and placing the hydrophobic monomer or the mixture of the hydrophobic monomer and the non-degradable component in a moisture environment for reacting for 1-5 days.

The hydrophobic coating is applied to delay the degradation behavior of the degradable material.

An absorbable implantable device comprises an absorbable substrate, wherein the surface of the absorbable substrate is covered with a hydrophobic coating.

Preferably, the absorbable matrix material is a degradable polymer, a corrodible metal, or a corrodible metal and degradable polymer composite.

Preferably, the absorbable implantable device further comprises an adhesive layer located between the absorbable matrix and the hydrophobic coating.

Preferably, the material of the adhesive layer is at least one selected from dopamine and silane coupling agents.

The absorbable implantable device is a cardiovascular stent, a cerebrovascular stent, a peripheral vascular stent, a biliary stent, an esophageal stent, an airway stent, a urethral stent, an occluder, an orthopedic implant or an absorbable suture.

The hydrophobic coating provided by the invention is formed by crosslinking hydrophobic monomers or hydrophobic monomers and non-degradable components, the hydrophobic monomers comprise degradable blocks, hydrophobic blocks and crosslinking functional groups, and when the hydrophobic coating is covered on the surface of a degradable material (such as a degradable matrix material), the hydrophobic blocks can enable the hydrophobic coating to play a good water-resisting role in the early stage, so that the degradable material is hardly degraded. At the later stage, the degradable block is degraded, and the degradation product slowly permeates the hydrophobic coating, so that the porosity of the hydrophobic coating is improved, body fluid can be in contact with the degradable matrix material through the pores of the hydrophobic coating, and the degradable matrix material starts to degrade at the moment. Therefore, the hydrophobic coating can delay the degradation of the degradable material.

Drawings

FIG. 1 is a schematic cross-sectional view of one embodiment of an absorbable implantable device;

FIG. 2 is a schematic cross-sectional view of another embodiment absorbable implantable device;

FIG. 3 is the molecular formula of the hydrophobic monomer of example 1;

FIG. 4 is a physical state diagram of the hydrophobic monomer of example 1;

FIG. 5A is a graph of the surface contact angle test results for PLA coatings of example 1;

FIG. 5B is a graph of the surface contact angle test results for the hydrophobic coating of example 1;

FIG. 6 is a graph of the corrosion profiles of the iron sheet of example 1 with different thickness of hydrophobic coating and the iron sheet with PLA-only coating;

FIG. 7 is the molecular formula of the hydrophobic monomer of example 2;

FIG. 8 is a physical state diagram of the hydrophobic monomer of example 2;

FIG. 9 is an Atomic Force Microscope (AFM) scan of the hydrophobic coating of example 2;

FIG. 10 is a graph of the corrosion profiles of the iron sheet of example 2 with different thickness of hydrophobic coating and the iron sheet with PLA-only coating;

FIG. 11 is an Atomic Force Microscope (AFM) scan of the hydrophobic coating of example 8;

FIG. 12 is a graph comparing the amount of hydrogen released in corrosion tests for the magnesium alloy sheet with the hydrophobic coating of example 8, and the bare magnesium alloy sheet;

FIGS. 13A-13B are surface element distribution diagrams of the organopolysilazane of example 11 at different curing times.

In the figure: 100-an absorbable matrix; 200-a hydrophobic coating; 300-an adhesive layer; 110-an outer surface; 120-an inner surface; 130-side.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. The following description sets forth numerous specific details to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The hydrophobic coating of an embodiment is a crosslinked coating formed by crosslinking a hydrophobic monomer. The hydrophobic monomer is a block copolymer comprising a hydrophobic block, a degradable block and a crosslinking functional group. Wherein, the hydrophobic block, the degradable block and the crosslinking functional group are connected through chemical bonds. The hydrophobic monomers are present in the form of crosslinks. The hydrophobic monomers are crosslinked to form a hydrophobic coating.

The hydrophobic block is formed by hydrophobic polymer, the degradable block is formed by degradable polymer, and the hydrophobic polymer and the degradable polymer are subjected to polymerization reaction, so that the hydrophobic block and the degradable block which are connected through chemical bonds are formed. The crosslinking functional group is connected with the hydrophobic block and/or the degradable block through a chemical bond and is used for promoting the crosslinking of the hydrophobic monomer.

A is used to represent the hydrophobic block, B is used to represent the degradable block, and C is used to represent the crosslinking functional group. In another embodiment, the crosslinking functional group C is not necessarily located at the terminal, and may be located at any position of the molecular chain of the hydrophobic monomer other than the terminal.

In one embodiment, the hydrophobic block is formed from at least one of polydimethylsiloxane, perfluoropolyether, polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, and polyvinylidene fluoride-hexafluoropropylene copolymer.

In one embodiment, the degradable blocks are formed from degradable polymers. In one embodiment, the degradable polymer is capable of degrading to produce an acidic product. In one embodiment, the degradable polymer is selected from at least one of polyglycolide, polyglycolic acid, poly-L-lactide, poly-D, L-lactide, polyhydroxybutyrate, poly-e-caprolactone, poly-e-alkyl substituted caprolactone, poly-delta-valerolactone, poly-beta-hydroxybutyrate, polycarbonate and polyether ester.

In further embodiments, the degradable polymer is a copolymer formed from at least two of the monomers in polyglycolide, polyglycolic acid, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly e-caprolactone, poly e-alkyl substituted caprolactone, poly delta-valerolactone, poly beta-hydroxybutyrate, polycarbonate and polyether ester.

In one embodiment, the crosslinking functional group is at least one selected from allyl, acryl, methacryl, epoxy, oxazoline, cyano, silicon hydroxyl, and siloxy.

In one embodiment, the hydrophobic coating comprises a hydrophobic monomer, and the same hydrophobic monomer is cross-linked to form the hydrophobic coating. In another embodiment, the hydrophobic coating comprises at least two different hydrophobic monomers that crosslink with each other to form the hydrophobic coating. Also, the mass ratio of the at least two different hydrophobic monomers may be any ratio.

When the hydrophobic coating is coated on the surface of the degradable material, for example, when the hydrophobic coating is arranged on the surface of the matrix formed by the degradable material, the hydrophobic block can enable the hydrophobic coating to play a good water-resisting role in an early stage, so that the matrix formed by the degradable material is hardly corroded or degraded in a water environment (for example, a blood environment). At the later stage, the degradable block is degraded, and the degradation product slowly permeates the hydrophobic coating, so that the porosity of the hydrophobic coating is improved, body fluid can be in contact with the degradable material through the pores of the hydrophobic coating, and at the moment, the degradable material starts to degrade. Thus, the hydrophobic coating can retard the degradation of the degradable material.

And when the degradable block is formed by the degradable polymer which can be degraded to generate an acid product, the degradable block is degraded to generate the acid product, so that a local slightly acidic environment can be generated around the degradable material, the degradation of the degradable material is further promoted, and the degradation of the degradable material in the later period is accelerated.

In one embodiment, the degradable block has a molecular weight of 500 to 20000. In another embodiment, the degradable block has a molecular weight of 1440-4080. In one embodiment, the degree of polymerization of the degradable block in the hydrophobic monomer is 20-40. Therefore, the degradation product of the degradable block in the hydrophobic monomer can be controlled, and the degradation behavior of the degradable material can be further regulated and controlled.

In another embodiment, the hydrophobic coating further comprises a non-degradable component. The non-degradable component is crosslinked to form a crosslinked network, and the hydrophobic monomer is dispersed in the crosslinked network. The non-degradable components are crosslinked to form a crosslinked network, so that the hydrophobic coating has better hydrophobic property, the corrosion or degradation of the degradable material can be delayed in the early stage, and in the later stage, along with the degradation of the degradable blocks in the hydrophobic monomer, the porosity of the hydrophobic coating is improved, so that body fluid can contact with the degradable matrix material through the pores of the hydrophobic coating, and at the moment, the degradable matrix material starts to degrade. In this embodiment, no crosslinking occurs between the hydrophobic monomers. In other embodiments, the hydrophobic monomers are crosslinked to each other and the non-degradable components are crosslinked to each other.

Specifically, the non-degradable component is selected from at least one of silicone rubber, polysiloxane, polysilazane, and a fluorine-containing polymer. In one embodiment, the silicone rubber is Dow Corning 184 silicone rubber and the polysilazane is an organo polysilazane.

In one embodiment, the hydrophobic coating is a coating formed by crosslinking a hydrophobic monomer with a non-degradable component. The crosslinking of the hydrophobic monomer and the non-degradable component means that the molecular chain of the hydrophobic monomer and the molecular chain of the non-degradable component are crosslinked, the hydrophobic monomer is not crosslinked, and the non-degradable component is not crosslinked.

In one embodiment, the mass ratio of the hydrophobic monomer to the non-degradable component is 1: 100-1: 0.01, whether the hydrophobic monomer exists in a non-crosslinked form or a crosslinked form, that is, whether the hydrophobic monomer is dispersed in the non-degradable component to form a crosslinked network to form a hydrophobic coating or the hydrophobic monomer is crosslinked with the non-degradable component to form a coating.

In one embodiment, the thickness of the hydrophobic coating is 0.01 to 100 μm. Through the thickness of reasonable setting hydrophobic coating to the degradation action of further regulation and control degradable material makes degradable material's degradation action can accord with the expectation. For example, when the hydrophobic coating is disposed on the substrate of the absorbable vascular stent, the hydrophobic coating can play a role of water isolation in the early stage of implantation, so as to delay the time point of starting corrosion or starting degradation of the substrate, avoid premature corrosion of the substrate, and ensure that the substrate can maintain sufficient radial support performance in the repair period of the vascular lesion. In the later stage of implantation, after the restoration of the lesion part is finished, the degradable block is degraded to generate an acidic degradation product, and the acidic degradation product can promote the corrosion or degradation of the matrix, so that the metal is degraded as soon as possible and absorbed by the matrix, thereby being beneficial to avoiding the long-term clinical risk.

In one embodiment, the thickness of the hydrophobic coating is 1-20 μm.

When the degradable block is formed by a degradable polymer which can be degraded to generate an acid product, the hydrophobic coating can regulate and control the behavior of the degradable material, namely delay the early degradation of the degradable material and accelerate the later degradation of the degradable material. Therefore, the hydrophobic coating can be applied to the field of controlling the degradation behavior of the degradable material. For example, the hydrophobic coating may be applied in the field of absorbable implantable devices.

A method of preparing a hydrophobic coating according to an embodiment includes the steps of:

step 110: providing a hydrophobic monomer, wherein the hydrophobic monomer is a block copolymer containing a hydrophobic block, a degradable block and a crosslinking functional group.

The hydrophobic monomers are the same as described above and will not be described further herein.

In one embodiment, the hydrophobic monomer is prepared using the following method:

a polymer (B-A-B-OH) containing a hydrophobic block and a degradable block at the terminal thereof is synthesized by using a polymer (A-OH) containing a terminal hydroxyl group and forming the hydrophobic block (both ends of which contain a hydroxyl group and the same meaning is expressed in the following expression and will not be described in detail) as an initiator, and then acryloyl chloride is reacted with the terminal hydroxyl group of the polymer (B-A-B-OH) containing a hydrophobic block and a degradable block at the terminal thereof to obtain a hydrophobic monomer containing an acryloyl group at the terminal thereof. The hydrophobic monomer synthesized by the method is C-B-A-B-C, and C is acryloyl.

For example, the hydrophobic block-forming polymer containing terminal hydroxyl groups is PDMS₇₆-OH, reacting PDMS₇₆Synthesis of PTMC with-OH as initiator₂₀-PDMS₇₆-PTMC₂₀-OH, followed by reaction of acryloyl chloride with PTMC₂₀-PDMS₇₆-PTMC₂₀Reaction with-OH to form PTMC₂₀-PDMS₇₆-PTMC₂₀-DA, i.e. a hydrophobic monomer. Wherein DA represents that both ends of a molecular chain of the hydrophobic monomer are acryloyl groups, and PDMS₇₆Denotes PDMS₇₆The form present in the hydrophobic monomer after the reaction (i.e., the hydrophobic block) is still represented by PDMS for convenience, which represents the PDMS block formed after the reaction of PDMS. The following expressions are the same and are not described in detail.

In a specific example, the synthesis of the polymer comprising a hydrophobic block and a degradable block having a hydroxyl group at the end (HO-B-A-B-OH) is carried out according to the synthetic methods in the documents G.M.Zentner, R.Rathi, C.Shih, J.C.McRea, M.H.Seo, H.Oh, B.G.Rhee, J.Mestecky, Z.Moldoverenun, M.Morgan, S.Weitman, Biodegradable polymers for delivery of proteins and water-insoluble drugs, J.control.Release 72(2001) 203-. Specific methods for reacting acryloyl chloride with terminal hydroxyl groups of polymers comprising a hydrophobic block and a degradable block, which contain hydroxyl groups at the terminal, are carried out according to the methods of documents Z.S.Ge, Y.M.Zhou, J.Xu, H.W.Liu, D.Y.Chen, S.Y.Liu, High-Efficiency preference of macromolecular Diblock copolymer via Selective Reaction in mesoporous Media, J.am.chem.Soc.131(2009) 1628-.

In another embodiment, A polymer containing A degradable block and A hydrophobic block at A terminal thereof (i.e., HO-A-B-A-OH) is synthesized using A polymer forming A degradable block containing A terminal hydroxyl group (i.e., B-OH) as an initiator, and then acryloyl chloride is reacted with the terminal hydroxyl group of the polymer containing A degradable block and A hydrophobic block at A terminal thereof to obtain A hydrophobic monomer. The hydrophobic monomer synthesized by the method is C-A-B-A-C, wherein C is acryloyl.

In other embodiments, when C is another crosslinking functional group, the terminal hydroxyl group of the polymer containing A degradable block and A hydrophobic block at the terminal thereof is reacted with A corresponding compound (HO-A-B-A-OH) or reacted with A polymer containing A hydrophobic block and A degradable block at the terminal thereof (HO-B-A-B-OH), for example, epichlorohydrin is reacted with the terminal hydroxyl group of the polymer containing A degradable block and A hydrophobic block at the terminal thereof to form A hydrophobic monomer having an epoxy group as A crosslinking functional group. Reacting triethoxysilylpropyl isocyanate with terminal hydroxyl of a polymer containing a degradable block and a hydrophobic block at the terminal to generate a hydrophobic monomer with a siloxane group as a crosslinking functional group.

In another example, when the crosslinking functional group C may be located at any position of the molecular chain of the hydrophobic monomer except the terminal, the hydrophobic monomer is synthesized by the method of references t.wang, m.yan, x.sun, d.quan, Polymer 57(2015) 21-28.

In one embodiment, the hydrophobic monomer is dissolved in a solvent to prepare a solution containing the hydrophobic monomer. The solution is applied to the surface of a substrate formed of a degradable material to form an uncrosslinked coating on the surface of the substrate. The solvent is a solvent capable of dissolving the hydrophobic monomer, such as ethyl acetate, acetone, acetonitrile, etc. The method of coating is any method known to those skilled in the art, such as ultrasonic spraying, spin coating, dip coating, or drop coating.

It should be noted that, in one embodiment, a hydrophobic monomer is dissolved in a solvent to prepare a solution containing only a hydrophobic monomer. In another embodiment, at least two different hydrophobic monomers may be dissolved in a solvent to prepare a solution containing at least two different hydrophobic monomers, and the at least two different hydrophobic monomers may be in any ratio.

Step 120: an initiation condition is applied to the hydrophobic monomer to crosslink the hydrophobic monomer to form the hydrophobic coating.

An inducing condition is applied to the uncrosslinked coating on the surface of the substrate, i.e., an inducing condition is applied to the hydrophobic monomer, so that the hydrophobic monomer is crosslinked to generate an elastic and rubbery hydrophobic coating.

In one embodiment, the triggering condition is ultraviolet light irradiation, heat treatment or moisture action.

In one embodiment, the method of inducing crosslinking by ultraviolet light irradiation comprises: hydrophobic monomer and photoinitiator are mixed and then irradiated by 365nm ultraviolet light for 30 min-2 h. Specifically, after a hydrophobic monomer is dissolved in a solvent to prepare a solution containing the hydrophobic monomer, before crosslinking, a photoinitiator is added into the solution containing the hydrophobic monomer, the solution containing the hydrophobic monomer is uniformly mixed and then coated on the surface of a matrix formed by degradable materials, and then the surface of the matrix is irradiated by 365nm ultraviolet light for 30 min-2 h to crosslink the hydrophobic monomers with each other, so that the hydrophobic coating is generated.

In one embodiment, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone. It is understood that in other embodiments, other photoinitiators capable of initiating crosslinking of the hydrophobic monomer under the influence of ultraviolet light may be used. The strength is 5000 to 15000 mu W/cm²Is irradiated for 30min to 2h under ultraviolet light, and the amount of the photoinitiator is enough to ensure that the hydrophobic monomer is fully crosslinked to generate an elastic and rubbery hydrophobic coating so that the hydrophobic coating has enough strength. In one embodiment, the mass of the photoinitiator is 1% o of the mass of the hydrophobic monomer.

In one embodiment, the method of heat treating to induce crosslinking comprises: treating the hydrophobic monomer at 20-150 ℃ for 30 min-72 h. Namely, the solution containing the hydrophobic monomer is coated on the surface of the matrix, an uncrosslinked coating is formed on the surface of the matrix, and then the substrate is treated at the temperature of 20-150 ℃ for 30 min-72 h, so that the hydrophobic monomer on the surface of the matrix is crosslinked to generate the hydrophobic coating covering the surface of the matrix.

In one embodiment, the step of moisture induced crosslinking comprises: and (3) placing the hydrophobic monomer in a moisture environment for reaction for 1-5 days. Wherein the moisture environment is an air environment or an atmosphere with a certain humidity.

In one embodiment, when the hydrophobic coating contains a non-degradable component, the non-degradable component is crosslinked by heat treatment. The method for inducing the crosslinking of the non-degradable component by the heat treatment comprises the following steps: dissolving a hydrophobic monomer in a solvent to prepare a solution containing the hydrophobic monomer, adding a non-degradable component into the solution containing the hydrophobic monomer, uniformly mixing, coating on the surface of a matrix formed by a degradable material, and treating at 20-150 ℃ for 30 min-72 h to enable the non-degradable component to be mutually crosslinked to form a crosslinked network, wherein the hydrophobic monomer is dispersed in the crosslinked network, so that the hydrophobic coating is generated.

In one embodiment, when the hydrophobic coating contains a non-degradable component, the non-degradable component is crosslinked using the action of moisture. The step of moisture induced crosslinking comprises: dissolving a hydrophobic monomer in a solvent to prepare a solution containing the hydrophobic monomer, adding a non-degradable component into the solution containing the hydrophobic monomer, uniformly mixing, coating on the surface of a matrix formed by a degradable material, then placing the matrix in a moisture environment for reacting for 2-5 days to enable the non-degradable component to be crosslinked to form a crosslinked network, and dispersing the hydrophobic monomer in the crosslinked network. Wherein the moisture environment is an air environment or an atmosphere with a certain humidity.

It should be noted that, when the hydrophobic coating contains hydrophobic monomers and non-degradable components, the non-degradable components and the hydrophobic monomers can be cross-linked with each other or only the non-degradable components are cross-linked with each other, and the hydrophobic monomers are not cross-linked with each other by selecting appropriate cross-linking conditions and appropriate ratios of the hydrophobic monomers to the non-degradable components.

The preparation method of the hydrophobic coating is simple in process and low in requirements on equipment, and the hydrophobic coating can be directly formed on the matrix of which the degradation behavior needs to be regulated and controlled in one step.

Further, an absorbable implantable device is provided. Referring to fig. 1, one embodiment of an absorbable implantable device comprises an absorbable substrate 100 and a hydrophobic coating 200 disposed on the surface of absorbable substrate 100.

Wherein the resorbable substrate 100 is formed from a bioabsorbable material (i.e., a degradable material). In one embodiment, the material of absorbable substrate 100 is a degradable polymer, a corrodible metal, or a corrodible metal and degradable polymer composite.

In one embodiment, the degradable polymer is selected from at least one of a degradable polyester and a degradable polyanhydride. Wherein the degradable polyester is at least one selected from polyglycolide, polyglycolic acid, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly epsilon-caprolactone, poly epsilon-alkyl substituted caprolactone, poly delta-valerolactone, poly beta-hydroxybutyrate, polycarbonate and polyether ester. The degradable polyanhydride is selected from at least one of poly (1, 3-bis (p-carboxyphenoxy) propane-sebacic acid, poly erucic acid dimer-sebacic acid and poly fumaric acid-sebacic acid.

In another embodiment, the degradable polymer is a copolymer of at least two of the monomers forming the aforementioned degradable polyester and degradable polyanhydride.

Corrodible metal refers to a corrodible pure metal or a corrodible alloy. In one embodiment, the corrodible metal is pure iron, an iron-based alloy, pure magnesium, a magnesium-based alloy, pure zinc, or a zinc-based alloy. In one embodiment, the corrodible metal is a treated corrodible metal, e.g., the corrodible metal is nitrided pure iron.

In one embodiment, a corrodible metal and degradable polymer composite refers to a material that is compression molded after the corrodible metal and degradable polymer are blended. The press-formed material is further processed to form absorbent substrate 100.

In another embodiment, a corrodible metal and degradable polymer composite refers to a material in which a corrodible metal and a degradable polymer are combined in a layered structure. For example, the substrate may be formed from a corrodible metal and the degradable polymer may be attached to the surface of the substrate in the form of a coating or film to form the resorbable substrate 100. Alternatively, the substrate may be formed from a degradable polymer and the corrodible metal may be attached to the surface of the substrate in the form of a coating or film to form the absorbable substrate 100.

In one embodiment, the corrodible metal is pure iron or an iron alloy, the degradable polymer is at least one of degradable polyester and degradable polyanhydride, and the degradable polymer is attached to the surface of the iron substrate in the form of a coating or a film to form the absorbable substrate 100. The hydrophobic coating 200 is coated on top of the degradable polymer coating. Early in the implantation period, the hydrophobic coating 200 protects the absorbable substrate 100 from degradation. When the degradable blocks in the hydrophobic coating 200 are degraded to form pores, the degradable polymer in the absorbable substrate 100 begins to degrade, and the acidic degradation product generated by degradation of the degradable blocks in the hydrophobic coating 200 and the acidic degradation product generated by the degradable polymer in the absorbable substrate 100 can accelerate corrosion of the iron substrate, so that early corrosion prevention and later corrosion acceleration of the absorbable medical device can be controlled.

Referring again to FIG. 1, absorbent substrate 100 has an outer surface 110, an inner surface 120, and sides 130. Wherein, when the absorbable implantable device is implanted in a diseased site, such as a blood vessel, the outer surface 110 is the surface in contact with the blood vessel wall and the inner surface 120 is the surface in direct contact with blood. The outer surface 110 is opposite the inner surface 120, and the side 130 connects the outer surface 110 and the inner surface 120. When the absorbable implantable device is implanted in other non-vascular lesions, the inner surface 120 is the surface that is in direct contact with the body fluids at the implantation site. The hydrophobic coating 200 covers at least the inner surface 120 of the absorbable substrate 100. the hydrophobic coating 200 can better isolate the inner surface 120 of the absorbable substrate 100 from bodily fluids early after implantation to avoid premature initiation corrosion or premature initiation degradation of the absorbable substrate 100.

As shown in FIG. 1, in one embodiment, the hydrophobic coating 200 completely covers all surfaces of the absorbable substrate 100, i.e., the outer surface 110, the inner surface 120, and the side surfaces 130 of the absorbable substrate 100 are completely covered by the hydrophobic coating 200. Thus, on the one hand, the hydrophobic coating 200 is a complete, continuous coating that helps to prevent the hydrophobic coating 200 from falling off during the process of expanding the absorbable substrate 100 after implantation; on the other hand, the hydrophobic coating 200 completely covers the entire surface of the absorbable substrate 100, which is advantageous for better protection of the absorbable substrate 100 at an early stage after implantation and for promoting uniform corrosion or uniform degradation of the absorbable substrate 100 at a later stage.

In another embodiment, the hydrophobic coating 200 only covers the inner surface 120 of the absorbable substrate 100, with no distribution of the hydrophobic coating 200 on both the outer surface 110 and the side 130 of the absorbable substrate 100. In other embodiments, hydrophobic coating 200 covers both outer surface 110 and inner surface 120 of absorbable substrate 100. Alternatively, hydrophobic coating 200 covers both inner surface 120 and sides 130 of absorbable substrate 100. The hydrophobic coating 200 thus provided also preferably retards the time point for initiating corrosion or initiating degradation of the absorbable substrate 100 during the early stage of implantation, and promotes rapid corrosion or rapid degradation of the absorbable substrate 100 at a later stage as the degradable blocks in the hydrophobic coating 200 degrade to produce acidic products.

The material of the hydrophobic coating 200 is the same as described above and will not be described in detail here. It should be noted that, when the degradable block in the hydrophobic coating 200 is degraded to generate an acidic product, the acidic product is continuously generated at the later stage of implantation along with the continuous degradation of the degradable block, and the acidic product can permeate from the hydrophobic coating 200 to the outside of the absorbable implantable device, so as to form a lower pH environment at the implantation site of the absorbable implantable device, thereby further promoting the rapid corrosion or degradation of the absorbable substrate 100. The hydrophobic coating 200 not only delays the point at which the resorbable substrate 100 initiates corrosion or initiates degradation, but also continuously regulates the degradation behavior of the resorbable substrate 100 from an early stage after implantation to a later stage after implantation. That is, the hydrophobic coating 200 retards the time point at which the absorbable substrate 100 starts to corrode or starts to degrade at an early stage after implantation, and prevents the absorbable substrate 100 from prematurely starting to corrode or start to degrade, thereby preventing the absorbable substrate 100 from prematurely losing mechanical support properties before repair of the diseased site is completed. After the repair of the lesion site is completed, the acidic products continuously generated by the degradable blocks can promote the rapid corrosion or the rapid degradation of the absorbable matrix 100, which is beneficial to avoiding the occurrence of long-term clinical risks.

By arranging the hydrophobic coating 200 with the thickness of only 0.01-100 mu m on the surface of the absorbable substrate 100, the degradation behaviors of the absorbable substrate 100 from the early stage to the later stage after implantation can be regulated, so that the degradation rate and the mechanical property of the absorbable substrate 100 (i.e. degradable material) and the time required by repairing the implanted part can be well matched, and the absorbable implantable device can meet the requirements of early support and later-stage rapid corrosion or degradation.

It is noted that when the thickness of the hydrophobic coating 200 is less than 0.01 μm, the hydrophobic coating 200 may degrade prematurely, resulting in insignificant effects on the time point for retarding the initiation of corrosion or initiation of degradation of the absorbable substrate 100; when the thickness of the hydrophobic coating 200 is greater than 100 μm, it may adversely affect the adherence of the absorbable implantable device to some extent, and may also increase the sheath resistance of the absorbable implantable device and cause delivery difficulties. Therefore, in one embodiment, the thickness of the hydrophobic coating 200 is 0.01 to 100 μm. The hydrophobic coating 200 with a thickness of only 0.01-100 μm can regulate and control the degradation behavior of the absorbable substrate 100 from the early stage after implantation to the later stage after implantation, and the setting of the thickness of the hydrophobic coating 200 within the range of 0.01-100 μm does not significantly increase the radial dimension of the absorbable implantable device after compression, so that the sheathing resistance of the absorbable implantable device is not significantly increased, and the difficulty in delivery is not caused.

In one embodiment, the thickness of the hydrophobic coating 200 is 1-20 μm, combining the factors of early water-blocking effect, late degradation or corrosion promotion, smooth transportation and adherence after implantation.

In one embodiment, referring to fig. 2, the resorbable implantable device further comprises an adhesive layer 300. The adhesive layer 300 is positioned between the absorbable substrate 100 and the hydrophobic coating 200. The adhesive layer 300 is provided to improve the bonding force between the hydrophobic coating 200 and the absorbable substrate 100, so that the hydrophobic coating 200 is reliably attached to the surface of the absorbable substrate 100, which is beneficial to preventing the hydrophobic coating 200 from falling off during the expansion process of the absorbable implantable device, thereby improving the reliability of the absorbable implantable device.

In one embodiment, the material of the adhesive layer 300 is at least one selected from dopamine and silane coupling agents. In other embodiments, the material of the adhesive layer 300 is not limited to dopamine and silane coupling agent, and any material with good adhesive property and biocompatibility can be applied to the adhesive layer 300.

It is understood that the adhesive layer 300 is distributed over the surface of the absorbable substrate 100 in the same manner as the hydrophobic coating 200 is distributed over the surface of the absorbable substrate 100.

The absorbable implantable device is any implantable device which needs to meet the requirements of early support and later rapid corrosion or degradation. For example, the absorbable implantable device is a cardiovascular stent, a cerebrovascular stent, a peripheral vascular stent, a biliary stent, an esophageal stent, an airway stent, a urethral stent, an occluder, an orthopedic implant, an absorbable suture, or the like.

The preparation method of the absorbable implantable device comprises the following steps: after the absorbable substrate 100 is prepared according to the method known by those skilled in the art, the hydrophobic coating 200 is formed on the absorbable substrate 100 by the same method as the above-mentioned hydrophobic coating, i.e., the solution containing the hydrophobic monomer is coated on the surface of the absorbable substrate 100 by the ultrasonic spraying, spin coating, dip coating or drop coating, and then the hydrophobic monomer and/or the non-degradable component on the surface of the absorbable substrate 100 are cross-linked by the cross-linking method such as ultraviolet irradiation, heat treatment or moisture action, so as to form the hydrophobic coating 200 on the surface of the absorbable substrate 100.

It is to be understood that when the resorbable implantable device further comprises an adhesive layer 300, the hydrophobic coating 200 covering the adhesive layer 300 is prepared after the adhesive layer 300 is prepared on the resorbable substrate 100. The adhesive layer 300 may be prepared by ultrasonic spraying, spin coating, dip coating, or drop coating, which are well known to those skilled in the art. In one embodiment, before preparing the adhesive layer 300, a step of surface treatment of the absorbable substrate 100 is further included to ensure that the adhesive layer 300 is reliably disposed on the surface of the absorbable substrate 100. For example, the surface of the absorbable substrate 100 is subjected to oxygen plasma treatment to form hydroxyl groups on the surface of the absorbable substrate 100, and the hydroxyl groups and the silane coupling agent are chemically bonded to each other to form the adhesive layer 300.

The hydrophobic coating and absorbable implantable device described above are further illustrated below in specific examples, the compositions of which are shown in table 1 for examples 1-19.

Examples 20 to 24 and comparative examples 1 to 4 the following test methods were used:

the method for measuring the metal weight loss of the in-vivo sample comprises the following steps: the animal is sacrificed after a period of time following implantation of the absorbable implantable device into the animal, and the absorbable implantable device is removed. A high resolution scan was performed using a micro-CT with a resolution of 5 μm and the results were processed to calculate the volume of undegraded metal and hence the weight loss to 1-volume of undegraded metal/initial metal volume.

Table 1 examples 1-19 hydrophobic coating compositions

Example 1

Cutting a pure iron sheet (purity is more than 99.9%) with the thickness of 200 mu m into 22mm multiplied by 26mm, sequentially polishing the pure iron sheet by using sand paper of 800 meshes, 1500 meshes, 2000 meshes and 3000 meshes, sequentially ultrasonically cleaning the polished iron sheet in acetone and absolute ethyl alcohol for 10min, then blowing the surface of the iron sheet by using nitrogen, and fully drying the iron sheet in an oven at the temperature of 60 ℃.

Polylactic acid (PLA) having a molecular weight of 6 ten thousand was dissolved in ethyl acetate to prepare a polylactic acid solution having a concentration of 0.01 g/mL. The polylactic acid solution is sprayed on the surface of the treated iron sheet by an ultrasonic spraying method to prepare the iron sheet with a PLA coating with the thickness of 4 mu m on the surface. The flow rate of liquid supplied by the pump in the spraying process is 0.1mL/min, and the ultrasonic power is 5.0W. The iron sheet with the PLA coating on the surface was placed in a fume hood to allow the ethyl acetate solvent to evaporate sufficiently.

The method referred to in the above document is first to prepare a bis-alkylhydroxy terminated Polydimethylsiloxane (PDMS)₇₆-OH) as initiator to synthesize PTMC with double hydroxyl at terminal₂₀-PDMS₇₆-PTMC₂₀-OH, the method of the re-reference uses reaction of acryloyl chloride with terminal hydroxyl groups to obtain acryloyl-terminated polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate, i.e., PTMC₂₀-PDMS₇₆-PTMC₂₀-DA。PTMC₂₀-PDMS₇₆-PTMC₂₀The structural formula and physical state of-DA are shown in FIGS. 3 and 4, respectively.

Adding a macromonomer PTMC₂₀-PDMS₇₆-PTMC₂₀-DA (i.e. hydrophobic monomer) was dissolved in ethyl acetate to prepare a solution containing hydrophobic monomer at a concentration of 0.02 g/mL; adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone into the solution containing the hydrophobic monomer to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. And spraying the mixed solution on the PLA coating surface of the iron sheet with the PLA coating by adopting an ultrasonic spraying method, wherein the liquid supply flow rate of a pump is 0.1mL/min in the spraying process, and the ultrasonic power is 4.75W. By controlling the spraying times, uncrosslinked PTMC with different thicknesses on the surface is prepared₂₀-PDMS₇₆-PTMC₂₀Samples of DA coating.

Using 365nm and 8000 mu W/cm of intensity²Ultraviolet light of (2) to the above uncrosslinked PTMC₂₀-PDMS₇₆-PTMC₂₀Irradiation of the DA coating for 1h to effect PTMC₂₀-PDMS₇₆-PTMC₂₀The acryloyl groups at the end of the DA react, thus crosslinking the hydrophobic monomers with each other. PTMC can be obviously observed after ultraviolet irradiation₂₀-PDMS₇₆-PTMC₂₀The DA coating is changed from the coating with weaker strength to oneThe elastic rubber coating forms a hydrophobic coating on the surface of the PLA coating of the iron sheet. The PLA coating and the hydrophobic coating were subjected to a water contact angle test, and the results are shown in fig. 5A and 5B, respectively, where the PLA coating had a contact angle of 100 ° and the hydrophobic coating had a contact angle of 114 °. Thus, the hydrophobic coating is more hydrophobic than a PLA coating. The thickness of the hydrophobic coatings was characterized by scanning electron microscopy, resulting in a thickness of 0.5 μm, 1.0 μm and 1.5 μm for each hydrophobic coating.

The iron sheet with the PLA coating only on the surface and the iron sheet with the PLA coating and the hydrophobic coating on the surface were edge sealed with 704 silicone rubber, leaving only one side of the coating exposed. And (3) after the 704 silica gel is completely solidified, placing the sample with the edge sealed in Hank's solution, carrying out corrosion experiments in a water bath shaker (50rpm,37 ℃), photographing the sample every week, and observing the corrosion condition. The results are shown in FIG. 6, in which 0 μm represents an iron sheet having only a PLA coating on the surface, 0.5 μm, 1.0 μm and 1.5 μm represent iron sheets having both a PLA coating and a hydrophobic coating on the surface, and the thicknesses of the hydrophobic coating are 0.5 μm, 1.0 μm and 1.5. mu.m, respectively. As can be seen from fig. 6, the hydrophobic coating can inhibit corrosion of the early iron and PLA coating composite, and as the thickness of the hydrophobic coating increases, the time during which iron corrosion is inhibited increases. When the thickness of the hydrophobic coating was 1.5 μm, there was only very slight corrosion of the iron sheet after 28 days of immersion.

Example 2

An iron piece of the same specification was treated in the same manner as in example 1 and a PLA coating of the same thickness was prepared on the surface of the iron piece.

Synthesis of acryloyl-terminated polylactic acid-polydimethylsiloxane-polylactic acid (PLA) in the same manner as in example 1₁₅-PDMS₇₆-PLA₁₅-DA) macromonomer (i.e.hydrophobic monomer), PLA₁₅-PDMS₇₆-PLA₁₅The structural formula and physical state of-DA are shown in FIG. 7 and FIG. 8, respectively.

Mixing PLA₁₅-PDMS₇₆-PLA₁₅Dissolving DA in ethyl acetate to prepare a hydrophobic monomer solution with the concentration of 0.02 g/mL; adding 2-hydroxy-2 photoinitiator into the solution containing hydrophobic monomer-methyl-1-phenyl-1-propanone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of the mass of the hydrophobic monomer. And spraying the mixed solution on the surface of the PLA coating of the iron sheet with the PLA coating by adopting an ultrasonic spraying method, wherein the liquid supply flow rate of a pump is 0.1ml/min and the ultrasonic power is 4.50W in the spraying process. Spraying once and twice respectively to form two uncrosslinked PLA layers with different thicknesses on the PLA coating layers of different iron sheets₁₅-PDMS₇₆-PLA₁₅-a DA coating.

Using 365nm and 8000 mu W/cm of intensity²Of the above uncrosslinked PLA₁₅-PDMS₇₆-PLA₁₅Irradiation of the DA coating for 1h to PLA₁₅-PDMS₇₆-PLA₁₅The acryloyl groups at the end of the DA react, thus crosslinking the hydrophobic monomers with each other. It can be observed that after ultraviolet irradiation, the coating is changed from the original sticky state into a smooth rubber state with certain toughness, namely a hydrophobic coating is formed on the surface of the PLA coating of the iron sheet. Scanning the crosslinked coating surface with an atomic force microscope revealed that the PLA blocks (degradable blocks) were phase separated from the non-degradable PDMS blocks (hydrophobic blocks) and the PLA phase was dispersed in the PDMS phase, as shown in FIG. 9. The two hydrophobic coatings were characterized by scanning electron microscopy to have a thickness of 0.5 μm and 1 μm, respectively.

And (3) sealing the edge of the iron sheet with the PLA coating layer on the surface and the iron sheet with the PLA coating layer and the hydrophobic coating layer on the surface by using 704 silicon gel, and exposing only one side of the coating layer. After 704 silica gel was solidified, the iron plate was placed in a 6-well plate, 5mL of Hank's solution was added to each well, and then the plate was put in a water bath shaker (50rpm,37 ℃) to perform the corrosion test, and the Hank's solution was changed every 24 hours. The iron pieces with different coatings were photographed and observed after 1 day, 2 days, 3 days and 5 days of the corrosion experiment, respectively. The results are shown in FIG. 10, in which 0 μm represents an iron sheet having only a PLA coating on the surface, 0.5 μm and 1.0 μm represent iron sheets having both a PLA coating and a hydrophobic coating on the surface, and the thickness of the hydrophobic coating is 0.5 μm and 1.0. mu.m, respectively. As can be seen from fig. 10, the hydrophobic coating significantly inhibited corrosion of the iron sheet under the PLA coating at 3 days of degradation, and the iron sheet with the hydrophobic coating also significantly corroded at 5 days, but at a lower degree than the iron sheet without the hydrophobic coating and with the PLA coating alone.

Example 3

The method referred to in the above document is first to prepare a bis-alkylhydroxy terminated Polydimethylsiloxane (PDMS)₇₆-OH) is used as an initiator to react with 2-methyl, 2-methyl acrylate-dimethylene carbonate to synthesize HO-Ac-PDMS with a functional group at the end₇₆-Ac-OH; then HO-Ac-PTMC₁₀-Ac-OH is taken as an initiator and reacts with trimethylene carbonate to obtain polytrimethylene carbonate-Ac-polydimethylsiloxane-Ac-polytrimethylene carbonate (PTMC) with the side group in the molecular chain containing acryloyloxy₂₀-Ac-PDMS₇₆-Ac-PTMC₂₀) Macromonomers (i.e., hydrophobic monomers).

Will PTMC₂₀-Ac-PDMS₇₆-Ac-PTMC₂₀Dissolving in ethyl acetate to prepare a solution with the concentration of 0.02g/mL and containing hydrophobic monomers; adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone into the solution containing the hydrophobic monomer to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. Spraying the mixed solution on the PLA coating surface of an iron sheet with a PLA coating by adopting an ultrasonic spraying method to obtain the non-crosslinked PTMC₂₀-Ac-PDMS₇₆-Ac-PTMC₂₀And (4) coating.

Using 365nm, intensity of 10000 uW/cm²Ultraviolet light of (2) to the above uncrosslinked PTMC₂₀-Ac-PDMS₇₆-Ac-PTMC₂₀Irradiating the coating for 2h to enable PTMC₂₀-Ac-PDMS₇₆-Ac-PTMC₂₀The double bonds of the pendant Ac groups react to crosslink the hydrophobic monomers with each other. It can be observed that after ultraviolet irradiation, the coating is changed from the original sticky state into a smooth rubber state with certain toughness, namely a hydrophobic coating is formed on the surface of the PLA coating of the iron sheet. The thickness of the resulting hydrophobic coating was 5 μm as characterized by scanning electron microscopy.

And (3) sealing the edge of the iron sheet with the PLA coating layer on the surface and the iron sheet with the PLA coating layer and the hydrophobic coating layer on the surface by using 704 silicon gel, and exposing only one side of the coating layer. After 704 silica gel was solidified, the iron plate was placed in a 6-well plate containing 5mL Hank's solution per well, and the plate was then placed in a water bath shaker (50rpm,37 ℃) for 28-day corrosion experiments, with the Hank's solution being changed every 24 hours. The corrosion was recorded by taking pictures of the samples every 7 days. The results show that after 7 days of immersion, severe corrosion had occurred to the surface of the iron sheet containing only the PLA coating. And when the PLA coating is provided with the hydrophobic coating, the surface of the iron sheet still hardly corrodes after being soaked for 28 days, and the metal luster is presented.

Example 4

Iron sheets of relevant specifications were processed in the same manner as in example 1 and PLA coating layers of the same thickness were prepared on the surfaces of the iron sheets.

Synthesis of acryloyl-terminated polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate (PTMC) in the same manner as in example 1₁₅-PDMS₇₆-PTMC₁₅-DA) macromonomers (i.e. hydrophobic monomers).

PTMC with the concentration of 0.02g/mL is prepared respectively₁₅-PDMS₇₆-PTMC₁₅And (2) mixing the DA and an ethyl acetate solution of a Dow Corning 184 silicon rubber precursor (in the Dow Corning 184 silicon rubber, the mass ratio of the basic component to the cross-linking agent is 10:1) with the concentration of 0.02g/mL to obtain a mixed solution, and spraying the mixed solution onto the PLA coating surface of the iron sheet by adopting an ultrasonic spraying method. And placing the silicon rubber precursor in a fume hood for 12 hours to enable the ethyl acetate to be continuously volatilized, and then placing the silicon rubber precursor in a 60-DEG C oven for 12 hours to enable the silicon rubber precursor to be crosslinked to form the hydrophobic coating. The results of the characterization under a scanning electron microscope showed that the thickness of the hydrophobic coating was 2.5 μm.

The edge sealing of the iron sheet with the PLA coating only on the surface and the iron sheet with the PLA coating and the hydrophobic coating on the surface was performed using 704 silicone rubber, leaving only one side of the coating exposed. The iron pieces were placed in 6-well plates and 5mL of Hank's solution was added to each well, and the plates were then placed in a water bath shaker (50rpm,37 ℃) for 28-day corrosion experiments, with the Hank's solution being changed every 24 hours. The corrosion was recorded by taking pictures of the samples every 7 days. The results show that after 7 days of immersion, severe corrosion had occurred to the surface of the iron sheet containing only the PLA coating. And when the PLA coating is coated with the hydrophobic coating, the surface of the iron sheet still hardly corrodes after being soaked for 21 days, the iron sheet presents metallic luster, and the surface of the iron sheet begins to darken at the 28 th day and has a sign of beginning to corrode.

Example 5

And (3) treating the iron sheet with the PLA coating on the surface under oxygen plasma, wherein the gas pressure is 50Pa, the plasma power is 100W, and the treatment time is 30 min. Sucking 50 μ L KH-570 silanized coupling agent with 100 μ L pipette, placing the pipette tip containing KH-570 and the iron sheet with PLA coating on the surface after plasma treatment into a drier, vacuumizing, standing for 12h to volatilize KH-570 and adsorb on the PLA coating surface to form KH-570 layer on the PLA coating.

Synthesis of acryloyl-terminated polylactic acid-polydimethylsiloxane-polylactic acid (PLA) in the same manner as in example 1₁₅-PDMS₇₆-PLA₁₅-DA) macromonomer (i.e. hydrophobic monomer).

Mixing PLA₁₅-PDMS₇₆-PLA₁₅dissolving-DA in ethyl acetate, preparing a solution containing a hydrophobic monomer with the concentration of 0.02g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. The mixed solution is respectively sprayed on the PLA coating surface of the iron sheet treated by silanization coupling agent and the PLA coating surface of the iron sheet not treated by silanization coupling agent by adopting an ultrasonic spraying method, the moving speed of an ultrasonic spray head along the x axis is 15mm/s, the step length of the ultrasonic spray head moving along the y axis is 2mm, the liquid supply flow rate of a pump is 0.1mL/min, the ultrasonic power is 4.5W, the spraying is repeated for five times according to the parameter, and the non-crosslinked PLA is formed on the PLA coating surface of the iron sheet₁₅-PDMS₇₆-PLA₁₅-a DA coating.

Using 365nm and 8000 mu W/cm of intensity²Ultraviolet light of (2) on uncrosslinked PLA₁₅-PDMS₇₆-PLA₁₅Irradiation of the DA coating for 1 hour to allow PLA to stand₁₅-PDMS₇₆-PLA₁₅The terminal acryloyl groups of the DA are crosslinked, thus forming a hydrophobic coating. After illumination, the coating can be changed from the original sticky state into a smooth rubbery coating with certain elasticity and toughness, and the thickness of the hydrophobic coating obtained by characterization under a scanning electron microscope is 3 mu m.

And (3) sealing the edge of the iron sheet with the PLA coating layer on the surface and the iron sheet with the PLA coating layer and the hydrophobic coating layer on the surface by using 704 silicon gel, and exposing only one side of the coating layer. After the 704 silica gel had solidified, each iron plate was placed in a glass dish containing 50mL of Hank's solution and placed in a water bath shaker (50rpm,37 ℃) for corrosion experiments, with the Hank's solution being changed every 24 hours. And (3) photographing the iron sheets with different coatings on the surfaces to observe the corrosion condition on 0 day, 1 day, 3 days, 5 days and 7 days of soaking respectively. The results show that the PLA-only coated iron sheet had corroded severely at day 3, the whole surface of the iron sheet appeared dark green, and the hydrophobic coating having a thickness of 3 μm had corroded only at individual sites on the surface of the iron sheet at day 7.

The hydrophobic coating was scratched with tweezers and compared to the adhesion of the hydrophobic coating to the substrate for the KH-570 treated samples and the samples without KH-570 treatment, the KH-570 treated samples were found to be more difficult to scratch. The KH-570 treatment shows that the binding force of the hydrophobic coating and the PLA coating is improved to a certain degree.

Example 6

Iron pieces of the same specification were treated in the same manner as in example 1, and 200. mu.L of PLA (M) having a concentration of 0.02g/mL was dropped on each of the iron pieces_w60kDa) was placed in a fume hood to completely volatilize the ethyl acetate and a PLA coating with a thickness of 4 μm was formed on the surface of the iron sheet.

Mixing PLA₁₅-PDMS₇₆-PLA₁₅-DA in Ethyl acetateIn ester, preparing a solution containing a hydrophobic monomer with the concentration of 0.2g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer; 4-5 drops of the mixture are quickly added onto the surface of the PLA coating of the iron sheet (8s) at a low rotating speed (1500r/min), and the iron sheet is rotated at a rotating speed of 3000r/min for 25s to finish the preparation of the coating, namely, uncrosslinked PLA is formed on the surface of the PLA coating of the iron sheet₁₅-PDMS₇₆-PLA₁₅-a DA coating.

Using 365nm and 8000 mu W/cm of intensity²Ultraviolet light of (2) on uncrosslinked PLA₁₅-PDMS₇₆-PLA₁₅Irradiation of the DA coating for 1 hour to allow PLA to stand₁₅-PDMS₇₆-PLA₁₅The terminal acryloyl groups of the DA are crosslinked, thus forming a hydrophobic coating. PLA can be observed after illumination₁₅-PDMS₇₆-PLA₁₅The DA coating is changed from the original sticky state to a smooth and tough rubbery state. The thickness of the hydrophobic coating was 5 μm as characterized under a scanning electron microscope.

And (3) sealing the edge of the iron sheet with the PLA coating layer on the surface and the iron sheet with the PLA coating layer and the hydrophobic coating layer on the surface by using 704 silicon gel, and exposing only one side of the coating layer. The iron pieces were placed in 6-well plates containing 10mL of Hank's solution per well, and the plates were then placed in a water bath shaker (50rpm,37 ℃) for a 14-day corrosion test, with the Hank's solution being changed every 24 hours. The corrosion was recorded by photographing the samples after 1 day, 3 days, 5 days, 7 days, and 14 days of immersion, respectively. The results show that after 1 day soaking, significant corrosion had occurred to the surface of the iron sheet containing only the PLA coating. And when a hydrophobic coating with the thickness of 5 mu m is arranged outside the PLA coating, the surface of the iron sheet is still hardly corroded after being soaked for 7 days, the metal luster is presented, and individual corroded sites are only appeared on the surface of the iron sheet on the 28 th day.

Example 7

Synthesis of terminal epoxy group-containing Compound according to substantially the same method as in example 1Polylactic acid-polydimethylsiloxane-polylactic acid (PLA)₁₅-PDMS₇₆-PLA₁₅DE) macromonomer (i.e.hydrophobic monomer), different from example 1, using epichlorohydrin with PLA containing hydroxyl groups at the end₁₅-PDMS₇₆-PLA₁₅And (3) carrying out an-OH reaction to generate a polylactic acid-polydimethylsiloxane-polylactic acid macromonomer containing an epoxy group at the tail end, namely a hydrophobic monomer. Wherein DE indicates that both ends of the molecular chain of the hydrophobic monomer are epoxy groups.

Mixing PLA₁₅-PDMS₇₆-PLA₁₅-DE is dissolved in ethyl acetate to make a solution containing hydrophobic monomers at a concentration of 0.02 g/mL; dissolving dialkyl hydroxyl terminated polydimethylsiloxane (PDMS-OH) in ethyl acetate to prepare a solution with the concentration of 0.02 g/mL; mixing the two solutions according to the volume ratio of 1:1 to obtain a mixed solution, coating the mixed solution on the surface of the PLA coating of the iron sheet by an ultrasonic spraying method, wherein the ultrasonic power is 4.5W in the spraying process, the liquid supply flow rate of a pump is 0.1mL/min, repeating the spraying for 5 times, and forming uncrosslinked PLA on the surface of the PLA coating of the iron sheet after the spraying is finished₁₅-PDMS₇₆-PLA₁₅Coatings of DE.

PLA having uncrosslinked surface₁₅-PDMS₇₆-PLA₁₅The iron sheet of the DE coating was heated in an oven at 60 ℃ for 12h to react the terminal epoxy groups of the macromer with the terminal hydroxyl groups of the PDMS-OH to give a crosslinked hydrophobic coating, which was observed to become stronger after heat treatment. The thickness of the hydrophobic coating was 2.5 μm as determined by scanning electron microscopy.

The sample was edge sealed and subjected to corrosion test in a water bath shaker in the same manner as in example 6, and the results of photographing and observing the corrosion morphology of the iron sheet showed that the entire surface of the iron sheet containing only the PLA coating had corroded when immersed for 3 days, whereas when the PLA coating was coated with a hydrophobic coating having a thickness of 2.5 μm, only a few corrosion dots appeared when immersed for 7 days, and most of the surface of the iron sheet remained un-corroded when immersed for 14 days.

Example 8

AZ31 magnesium alloy sheet with thickness of 500 μm and size of 22mm × 26mm is sequentially polished with 800 mesh and 2000 mesh sandpaper, sequentially ultrasonically cleaned with acetone and anhydrous ethanol for 10min, and blow-dried with nitrogen.

Synthesis of acryloyl-terminated polylactic acid-polydimethylsiloxane-polylactic acid (PLA) in the same manner as in example 1₁₇-PDMS₇₆-PLA₁₇-DA) macromonomers (i.e. hydrophobic monomers).

Mixing PLA₁₇-PDMS₇₆-PLA₁₇dissolving-DA in ethyl acetate, preparing a solution containing a hydrophobic monomer with the concentration of 0.1g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. Dripping 0.5mL of the mixed solution on each magnesium alloy sheet, placing the magnesium alloy sheet in a fume hood, volatilizing ethyl acetate to form uncrosslinked PLA on the surface of the magnesium alloy sheet₁₇-PDMS₇₆-PLA₁₇-a coating of DA.

Using 365nm and 8000 mu W/cm of intensity²Ultraviolet light of (2) on uncrosslinked PLA₁₇-PDMS₇₆-PLA₁₇The DA coating is irradiated for 1 hour to react the terminal acryl groups and obtain a crosslinked hydrophobic coating. After the ultraviolet irradiation, a layer of rubber coating with certain toughness can be formed on the surface of the magnesium alloy sheet. From the scanning of the coating surface by atomic force microscope, it can be seen that the degradable PLA blocks and the non-degradable PDMS blocks in the hydrophobic coating are clearly phase separated and the PLA phase is dispersed in the PDMS phase, as shown in fig. 11. The thickness of the hydrophobic coating was 10 μm, characterized under a scanning electron microscope.

And (3) sealing edges of the bare magnesium alloy sheet and the magnesium alloy sheet with the hydrophobic coating by using 704 silica gel, wherein the hydrophobic coating is bare in the magnesium alloy sheet sample with the hydrophobic coating. After the 704 silica gel was solidified, each sample was placed in a beaker with 200mL of PBS, and the beaker was placed in a water bath shaker (50rpm,37 ℃) and the amount of hydrogen generated by corrosion of the magnesium alloy was collected by the inverted funnel method. As a result, as shown in fig. 12, the magnesium alloy having the hydrophobic coating on the surface thereof produced significantly less hydrogen gas than the magnesium alloy without the coating group (bare magnesium alloy sheet) in 14 days of corrosion, demonstrating that the hydrophobic coating can be used to slow down the corrosion of the magnesium alloy.

Example 9

A sheet of AZ31 magnesium alloy of the same specification was processed in the same manner as in example 8.

Synthesis of methacryloyl-terminated polycaprolactone-PFPE-Polycaprolactone (PCL) Using bishydroxy-terminated perfluoropolyether (PFPE-OH) as initiator in substantially the same manner as in example 1₂₀-PFPE-PCL₂₀DMA) macromer (i.e. hydrophobic monomer).

Adding PCL₂₀-PFPE-PCL₂₀-DMA is dissolved in ethyl acetate to prepare a solution containing a hydrophobic monomer with the concentration of 0.1g/mL, and 2-hydroxy-2-methyl-1-phenyl-1-acetone serving as a photoinitiator is added to obtain a mixture, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. 0.5mL of the above-mentioned mixed solution was dropped on each magnesium alloy sheet, and the magnesium alloy sheet was placed in a fume hood to evaporate ethyl acetate, thereby forming non-crosslinked PCL on the surface of the magnesium alloy sheet₂₀-PFPE-PCL₂₀-coating of DMA.

Using 365nm, the intensity is 15000 mu W/cm²Ultraviolet light on uncrosslinked PCL₂₀-PFPE-PCL₂₀DMA coating irradiation for 1 hour to react the terminal methacryloyl groups in the coating to give a crosslinked hydrophobic coating. After ultraviolet irradiation, the coating can be seen to be changed into a smooth coating with certain toughness from the original state of being scratched with a little tweezers. The thickness of the hydrophobic coating was 10 μm, characterized under a scanning electron microscope.

And (3) sealing edges of the bare magnesium alloy sheet and the magnesium alloy sheet with the hydrophobic coating by using 704 silica gel, wherein the hydrophobic coating is bare in the magnesium alloy sheet sample with the hydrophobic coating. After the 704 silica gel was solidified, each sample was placed in a beaker with 200mL of PBS, and the beaker was placed in a water bath shaker (50rpm,37 ℃) and the amount of hydrogen generated by corrosion of the magnesium alloy was collected by the inverted funnel method. The results show that the volume of the magnesium alloy without the coating group for continuously releasing hydrogen in 14 days is about 10mL, and the magnesium alloy with the hydrophobic coating on the surface hardly collects hydrogen in 14 days of corrosion, thereby proving that the hydrophobic coating can be used for slowing down the corrosion of the magnesium alloy.

Example 10

Synthesis of acryloyl-terminated polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate (PTMC) in the same manner as in example 1₁₉-PDMS₇₆-PTMC₁₉-DA) macromonomers (i.e. hydrophobic monomers).

Will PTMC₁₉-PDMS₇₆-PTMC₁₉dissolving-DA in ethyl acetate, preparing a solution containing a hydrophobic monomer with the concentration of 0.1g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixture, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. 0.5mL of the above-mentioned mixed solution was dropped on each magnesium alloy sheet, and the magnesium alloy sheet was placed in a fume hood to evaporate ethyl acetate, thereby forming non-crosslinked PTMC on the surface of the magnesium alloy sheet₁₉-PDMS₇₆-PTMC₁₉-a coating of DA.

Using 365nm and 5000 mu W/cm of intensity²Ultraviolet light of (2) on uncrosslinked PTMC₁₉-PDMS₇₆-PTMC₁₉The DA coating is irradiated for 1 hour to react the terminal acryl groups in the coating to obtain a crosslinked hydrophobic coating. After ultraviolet irradiation, the coating can be seen to be changed into a smooth coating with certain toughness from the original state of being scratched with a little tweezers. The thickness of the hydrophobic coating was 10 μm, characterized under a scanning electron microscope.

And (3) sealing edges of the bare magnesium alloy sheet and the magnesium alloy sheet with the hydrophobic coating by using 704 silica gel, wherein the hydrophobic coating is bare in the magnesium alloy sheet sample with the hydrophobic coating. After the 704 silica gel was solidified, each sample was placed in a beaker with 200mL of PBS, and the beaker was placed in a water bath shaker (50rpm,37 ℃) and the amount of hydrogen generated by corrosion of the magnesium alloy was collected by the inverted funnel method. As a result, as shown in fig. 12, the magnesium alloy having the hydrophobic coating on the surface thereof exhibited a cumulative hydrogen gas release volume of about 1mL in 14 days of corrosion, and almost no hydrogen gas release was observed for the first 6 days of the corrosion test, while the volume of hydrogen gas released continuously in 14 days without the coating group was about 10mL, demonstrating that the hydrophobic coating was useful for reducing corrosion of the magnesium alloy.

Example 11

Synthesis of acryloyl-terminated polylactic acid-polydimethylsiloxane-polylactic acid (PLA) in the same manner as in example 1₁₅-PDMS₇₆-PLA₁₅-DA) macromonomers (i.e. hydrophobic monomers).

Mixing PLA₁₅-PDMS₇₆-PLA₁₅Blending the-DA and the organic polysilazane in a mass ratio of 1:10 to prepare an ethyl acetate mixed solution with a total mass concentration of 0.2 g/mL; adsorbing the processed magnesium alloy sheet on a sample platform of a spin coater by using negative pressure, dripping 6-8 drops of the mixed solution on the surface of the magnesium alloy sheet at a low rotation speed (1500r/min, 10s), rotating at 2000r/min for 25s to form non-crosslinked PLA on the surface of the magnesium alloy sheet₁₅-PDMS₇₆-PLA₁₅DA coating and then placing the sample in air to allow the Si-N bonds and N-H bonds in the polysilazane to react for 5 days under the action of moisture. From the results of the surface elemental analysis, it can be seen that no N element was detected in the coating on day 5 as compared to day 1 of curing, as shown in fig. 13A and 13B, respectively, indicating that the polysilazane had been completely crosslinked to form a hydrophobic coating. The thickness of the hydrophobic coating was 8 μm, characterized under a scanning electron microscope.

And (3) sealing edges of the bare magnesium alloy sheet and the magnesium alloy sheet with the hydrophobic coating by using 704 silica gel, wherein the hydrophobic coating is bare in the magnesium alloy sheet sample with the hydrophobic coating. After the 704 silica gel is solidified, the bare magnesium alloy sheet with the edge sealed and the magnesium alloy sheet with the hydrophobic coating are respectively placed in a six-hole plate filled with 5mL of Hank's liquid, and are placed in a water bath shaking table (50rpm,37 ℃) for corrosion experiments, and the Hank's liquid is replaced every 24 hours. On day 28, the etching solution was taken and the concentration of magnesium ions in the solution was measured by inductively coupled plasma emission spectroscopy (ICP-OES). The result shows that after the magnesium alloy sheet is soaked for 28 days, the concentration of magnesium ions generated by corrosion of the bare magnesium alloy sheet is 138.1mg/L, the concentration of magnesium ions generated by corrosion of the magnesium alloy sheet under the hydrophobic coating is 30.4mg/L, and the hydrophobic coating still has an obvious inhibiting effect on the corrosion of the magnesium alloy sheet after the magnesium alloy sheet is soaked for 28 days.

Example 12

Cutting a pure magnesium sheet with the thickness of 200 mu m into 22mm multiplied by 26mm, sequentially polishing the pure magnesium sheet by using sand paper of 800 meshes, 1500 meshes, 2000 meshes and 3000 meshes, sequentially ultrasonically cleaning the polished pure magnesium sheet in acetone and absolute ethyl alcohol for 10min, and drying the cleaned pure magnesium sheet by using nitrogen.

Synthesis of acryloyl-terminated polylactic acid-polydimethylsiloxane-polylactic acid (PLA) in the same manner as in example 1₁₀-PDMS₇₆-PLA₁₀-DA) macromonomer (i.e. hydrophobic monomer) and acryloyl terminated polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate (PTMC)₂₀-PDMS₇₆-PTMC₂₀-DA) macromonomers (i.e. hydrophobic monomers).

Mixing PLA₁₀-PDMS₇₆-PLA₁₀-DA and PTMC₂₀-PDMS₇₆-PTMC₂₀dissolving-DA in ethyl acetate according to the mass ratio of 1:1, preparing a solution containing two hydrophobic monomers with the total mass concentration of 0.2g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomers. Adsorbing the processed pure magnesium sheet on a sample table of a spin coater by utilizing negative pressure, dripping 6-8 drops of the mixed solution on the surface of the pure magnesium sheet at a low rotating speed (1500r/min, 8s), rotating for 30s while keeping the rotating speed at 2000r/min, volatilizing ethyl acetate in a fume hood, and forming non-crosslinked PLA on the surface of the pure magnesium sheet₁₀-PDMS₇₆-PLA₁₀-DA and PTMC₂₀-PDMS₇₆-PTMC₂₀-a mixed coating of DA.

Subjecting uncrosslinked PLA₁₀-PDMS₇₆-PLA₁₀-DA and PTMC₂₀-PDMS₇₆-PTMC₂₀-DA mixed coating placed at 365nm and an intensity of 8000. mu.W/cm²Is irradiated for 1 hour under ultraviolet light to react the terminal acryl group to form a hydrophobic coating. After the ultraviolet irradiation, the coating can be seen to be changed from the original sticky state into a rubber state with certain toughness, which indicates that the macromolecular monomer is crosslinked. Characterization under a scanning electron microscope gave a thickness of 5 μm for the hydrophobic coating.

And (3) sealing edges of the bare magnesium alloy sheet and the magnesium alloy sheet with the hydrophobic coating by using 704 silica gel, wherein the hydrophobic coating is exposed outside in the magnesium alloy sheet sample with the hydrophobic coating. After 704 silica gel was solidified, the edge-sealed sample was placed in a beaker containing 200mL of Hank's solution, and the amount of hydrogen released by magnesium corrosion was measured by the inverted funnel method, and the corrosion test was performed in a water bath shaker (50rpm,37 ℃). The result shows that the volume of the accumulated released hydrogen of the bare pure magnesium sheet after 7 days of corrosion is about 12mL, and the volume of the accumulated released hydrogen of the pure magnesium sheet with the hydrophobic coating after corrosion is about 0.5mL, which indicates that the hydrophobic coating can well inhibit the early corrosion of the pure magnesium.

Example 13

Pure magnesium chips of the same specification were processed in the same manner as in example 12.

Polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate (PTMC) having trimethoxy silicon group at the terminal was synthesized in substantially the same manner as in example 1₂₀-PDMS₇₆-PTMC₂₀DTS) macromonomer (i.e. hydrophobic monomer), different from example 1, using trisilyltrisiloxy isocyanate with PTMC containing a hydroxyl group at the end₂₀-PDMS₇₆-PTMC₂₀-OH to form a polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate macromonomer containing trimethoxy silicon groups at the ends, i.e., a hydrophobic monomer. Wherein DTS represents that two ends of a molecular chain of the hydrophobic monomer are trimethoxy silicon groups.

Will PTMC₂₀-PDMS₇₆-PTMC₂₀-DTS is dissolved in ethyl acetate to prepare solutions containing hydrophobic monomers with mass concentrations of 0.1g/mL and 0.5g/mL respectively; dripping 0.2mL of the above two solutions containing hydrophobic monomer with different concentrations on different pure magnesium sheets, placing in a fume hood, volatilizing ethyl acetate, and forming non-crosslinked PTMC on the surface of the pure magnesium sheets₂₀-PDMS₇₆-PTMC₂₀-a coating of DTS.

At room temperature, the PTMC with uncrosslinked surface₂₀-PDMS₇₆-PTMC₂₀-DTS coated pure magnesium pieces were left in air for 3 days and the terminal trimethoxy silicon group was hydrolyzed with moisture to produce siliconHydroxyl, and the dehydration reaction between silicon hydroxyl is utilized to realize the crosslinking of hydrophobic monomers, so as to generate a crosslinked hydrophobic coating. The crosslinked coating is changed from the original sticky state into a rubber state with certain toughness. The thickness of the hydrophobic coating prepared from the solutions at the two concentrations was 20 μm and 100 μm, respectively, as characterized by a scanning electron microscope.

And (3) sealing the processed bare pure magnesium sheet and the pure magnesium sheet with the hydrophobic coating by using 704 silica gel, so that the surface with the hydrophobic coating is exposed outside. After 704 silica gel was solidified, the edge-sealed sample was placed in a beaker containing 200mL of Hank's solution, and the amount of hydrogen released by magnesium corrosion was measured by the inverted funnel method, and the corrosion test was performed in a water bath shaker (50rpm,37 ℃). The results show that the volume of the accumulated released hydrogen of the bare pure magnesium sheet after 14 days of corrosion is about 23mL, the volume of the accumulated released hydrogen of the pure magnesium sheet with the hydrophobic coating with the thickness of 20 μm on the surface is about 0.8mL, and the hydrogen is not collected in the pure magnesium sheet group with the hydrophobic coating with the thickness of 100 μm on the surface. The hydrophobic coating can well inhibit early corrosion of pure magnesium.

Example 14

A polyglycolide-lactide copolymer (PLGA, LA: GA 50:50) having a molecular weight of 6 ten thousand was hot-pressed at 120 ℃ to prepare a PLGA sheet having a thickness of 300 μm and a size of 22 mm. times.26 mm.

Synthesis of acryloyl-terminated polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate (PTMC) in the same manner as in example 1₂₀-PDMS₇₆-PTMC₂₀-DA) macromonomers (i.e. hydrophobic monomers).

Will PTMC₂₀-PDMS₇₆-PTMC₂₀dissolving-DA in ethyl acetate to prepare 0.5g/mL solution containing hydrophobic monomer, and adding 2-hydroxy-2-methyl-1-phenyl-1-acetone as photoinitiator to obtain mixed solution, wherein the mass of the photoinitiator is 1 per mill of that of the hydrophobic monomer. 4-6 drops of the mixed solution are dripped at a low rotating speed (1500r/min, 10s), then spin coating is carried out at a rotating speed of 2000r/min for 25s, and non-crosslinked PTMC is generated on the surface of a PLGA sheet₂₀-PDMS₇₆-PTMC₂₀-a DA coating.

At 365nm and 8000 muW/cm²Ultraviolet light of (2) on uncrosslinked PTMC₂₀-PDMS₇₆-PTMC₂₀The DA coating is irradiated for 1 hour to react the terminal acryloyl groups in the macromer to obtain a crosslinked hydrophobic coating. The hydrophobic coating formed after ultraviolet irradiation has certain toughness and elasticity. The thickness of the resulting hydrophobic coating was characterized by 10 μm under a scanning electron microscope.

The bottom and periphery of the PLGA sheet were sealed with 704 silicone tape to ensure that only the test side or the side with the hydrophobic coating was exposed. After the 704 silica gel was completely solidified, the PLGA sheets were immersed in Hank's solution and the degradation experiments were performed in a 37 ℃ water bath shaker with the PLGA sheet without the hydrophobic coating as a control. After 28 days of degradation, the PLGA tablets were subjected to a permeation gel chromatography (GPC) test, the GPC results showing that PLGA with the hydrophobic coating had a higher molecular weight than the PLGA without the coating group (naked PLGA tablets). According to the method, the hydrophobic coating is coated on the surface of the PLGA sheet, so that the purpose of slowing down PLGA degradation is achieved.

Example 15

Pure zinc sheets with thickness of 200 μm and size of 22mm × 26mm were sequentially polished with 800 mesh and 2000 mesh sandpaper, and sequentially ultrasonically cleaned with acetone and absolute ethanol for 10min, and the surface was blow-dried with nitrogen.

Synthesis of acryloyl-terminated polycaprolactone-polydimethylsiloxane-Polycaprolactone (PCL) in substantially the same manner as in example 1₁₅-PDMS₇₆-PCL₁₅-DA) macromonomers (i.e. hydrophobic monomers).

Adding PCL₁₅-PDMS₇₆-PCL₁₅dissolving-DA in ethyl acetate, preparing a solution containing a hydrophobic monomer with the concentration of 0.02g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. Spraying the mixed solution on the surface of a treated pure zinc sheet by adopting an ultrasonic spraying method, wherein the flow rate of liquid supplied by a pump in the spraying process is 0.1mL/min, and the ultrasonic power is 5.0W; placing the sample in a fume hood to fully volatilize ethyl acetate, and forming non-crosslinked PCL on the surface of the pure zinc sheet₁₅-PDMS₇₆-PCL₁₅-a DA coating.

Using 365nm and the intensity is 12000 mu W/cm²Ultraviolet light on uncrosslinked PCL₁₅-PDMS₇₆-PCL₁₅And irradiating the DA coating for 40min to react acryloyl groups in the coating to obtain a cross-linked hydrophobic coating, wherein the coating is changed from an original non-scratch-resistant state into a rubber state with certain toughness. The thickness of the hydrophobic coating was 5 μm, characterized under a scanning electron microscope.

And (3) sealing the bare pure zinc sheet and the pure zinc sheet with the hydrophobic coating on the surface by using 704 silica gel, exposing only the testing surface (namely the hydrophobic coating and the corresponding surface of the bare pure zinc sheet), immersing each sample in 10mL of Hank's solution after the 704 silica gel is solidified, and performing a corrosion experiment in a water bath shaker (37 ℃,50 rpm). The result shows that the surface of the bare pure zinc sheet is completely corroded when the sheet is soaked for 1 day, and the pure zinc sheet with the hydrophobic coating on the surface is not corroded by 28 days.

Example 16

Pure zinc flakes of the same specification were treated in the same manner as in example 15.

Mixing PLA₁₅-PDMS₇₆-PLA₁₅Blending the-DA and the organic polysilazane in a mass ratio of 1:100, and preparing an ethyl acetate solution with a total mass concentration of 0.02 g/mL; adsorbing the treated pure zinc sheet on a sample table of a spin coater by using negative pressure, dripping 6-8 drops of the ethyl acetate solution on the surface of the pure zinc sheet at a low rotating speed (2000r/min, 10s), then keeping the rotating speed at 4000r/min, rotating for 25s, and forming non-crosslinked PLA on the surface of the pure zinc sheet₁₅-PDMS₇₆-PLA₁₅-a blended coating of DA with an organic polysilazane.

Taking off prepared non-crosslinked PLA₁₅-PDMS₇₆-PLA₁₅Samples of a blended coating of DA and an organic polysilazane exposed to air at room temperature to react Si-N bonds and N-H bonds in the organic polysilazane under the action of moisture for 5 days to cause the coating to occurCrosslinking to produce a hydrophobic coating. The thickness of the hydrophobic coating was 0.01 μm, characterized under a scanning electron microscope.

And (3) sealing the bare pure zinc sheet and the pure zinc sheet with the hydrophobic coating on the surface by using 704 silica gel, exposing only the testing surface (namely the hydrophobic coating and the corresponding surface of the bare pure zinc sheet), immersing each sample in 10mL of Hank's solution after the 704 silica gel is solidified, and performing a corrosion experiment in a water bath shaker (37 ℃,50 rpm). The results show that the surface of the bare pure zinc sheet is corroded comprehensively when the sheet is soaked for 1 day, and only individual sites of the pure zinc sheet with the hydrophobic coating on the surface are corroded by 3 days.

Example 17

Will PTMC₂₀-PDMS₇₆-PTMC₂₀dissolving-DA in ethyl acetate to prepare a solution containing a hydrophobic monomer with the concentration of 0.3g/mL, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of that of the hydrophobic monomer. Soaking PLA filament with molecular weight of 10 ten thousand and diameter of 200 μm in the above solution for 10s, and pulling at 2000 μm/s to form a layer of uncrosslinked PTMC on the surface of the PLA filament₂₀-PDMS₇₆-PTMC₂₀-a DA coating.

Using 365nm, the intensity is 15000 mu W/cm²Ultraviolet light of (2) on uncrosslinked PTMC₂₀-PDMS₇₆-PTMC₂₀DA irradiation for 30min to react the acryloyl groups in the coating to give a crosslinked hydrophobic coating. The thickness of the hydrophobic coating was 5 μm, characterized under a scanning electron microscope.

Sealing two ends of the PLA wire which is not covered by the hydrophobic coating by using 704 silica gel, soaking the PLA wire with the hydrophobic coating on the surface in a glass dish filled with 50mL of Hank's liquid after the 704 silica gel is solidified, and performing a degradation experiment in a water bath shaker (50rpm,37 ℃) by using the PLA wire with the non-coating on the surface as a control. After 28 days of degradation, the tensile property test is carried out on the PLA filaments with different degradation times, and the result shows that the tensile strength of the PLA filaments with the hydrophobic coating on the surface is equivalent to that before the degradation test after 28 days of degradation, while the mechanical property of the PLA filaments without the coating on the surface is obviously reduced, which indicates that the hydrophobic coating can delay the degradation of the PLA filaments, so that the slow reduction of the early mechanical property of the PLA filaments can be maintained.

Example 18

A pure iron wire (iron content is more than 99.9%) with the diameter of 200 mu m is sequentially polished by SiC sand paper with 800 meshes and 2000 meshes, the pure iron wire is wound on a screw with the diameter of 5mm into a spring with the length of 3cm, and is sequentially ultrasonically cleaned by acetone and absolute ethyl alcohol for 10min and then is dried by nitrogen.

PLA (M) was prepared at a concentration of 0.1g/mL_w60kDa) in a PLA solution, the spring wound from pure iron wire was dipped for 10s, pulled at a speed of 2000 μm/s, and suspended in a fume hood to evaporate the ethyl acetate and form a PLA coating on the surface of the spring.

Adding PCL₁₅-PDMS₇₆-PCL₁₅the-DA and Dow Corning 184 silicon rubber precursor (in Dow Corning 184 silicon rubber, the mass ratio of the basic component to the cross-linking agent is 10:1) are blended according to the mass ratio of 1:5 to prepare an ethyl acetate solution with the total concentration of 0.2 g/mL. Immersing the spring-shaped pure iron wire with the PLA coating on the surface in the solution, and rapidly pulling at the speed of 4000 mu m/s to form non-crosslinked PCL on the surface of the PLA coating of the spring-shaped pure iron wire₁₅-PDMS₇₆-PCL₁₅-a blended coating of DA with dow corning 184 silicone rubber precursor.

The PCL with non-crosslinked surface₁₅-PDMS₇₆-PCL₁₅Suspending and placing the spring-shaped pure iron wires of the blended coating of the-DA and Dow Corning 184 silicon rubber precursor for 24h, so that the cross-linking of the blended coating on the surface is carried out at normal temperature to generate a cross-linked hydrophobic coating, and the coating can be seen from the original stateThe sticky state of the rubber becomes a smooth and tough rubber state. The thickness of the hydrophobic coating was 4 μm, characterized under a scanning electron microscope.

The spring-like plain iron wire with only a PLA coating on the surface and the spring-like plain iron wire with both a PLA coating and a hydrophobic coating on the surface were soaked in Hank's solution and subjected to corrosion experiments in a water bath shaker (37 ℃,50 rpm). The results show that after soaking for 7 days, the pure iron wire with only PLA coating on the surface has been severely corroded and broken at partial sites, while the spring-shaped pure iron wire with hydrophobic coating on the surface has almost no corrosion, and the spring-shaped pure iron wire still maintains the mechanical properties equivalent to the initial state until 28 days.

Example 19

Iron wire of the same gauge was treated in the same way as in example 18 and the same PLA coating was prepared on the surface.

polycaprolactone-polydimethylsiloxane-Polycaprolactone (PCL) having triethoxysilyl group at the end was synthesized in substantially the same manner as in example 1₁₀-PDMS₇₆-PCL₁₀DS) macromonomers (i.e.hydrophobic monomers). Wherein DS represents that two ends of a molecular chain of the hydrophobic monomer are triethoxysilylpropyl.

Adding PCL₁₀-PDMS₇₆-PCL₁₀DS is dissolved in ethyl acetate to prepare a solution containing the hydrophobic monomer at a concentration of 0.5 g/mL. Immersing the spring-shaped pure iron wire with the PLA coating on the surface in the solution, and rapidly pulling at the speed of 4000 mu m/s to form non-crosslinked PCL on the surface of the spring-shaped pure iron wire₁₀-PDMS₇₆-PCL₁₀-a DS coating.

At room temperature, the PCL with the uncrosslinked surface is added₁₀-PDMS₇₆-PCL₁₀And (3) hanging the pure iron wire of the DS coating for 48h, hydrolyzing terminal triethoxysilylpropyl by utilizing moisture in the air to generate silicon hydroxyl, and realizing the crosslinking of the coating through dehydration reaction among the silicon hydroxyl to form a crosslinked hydrophobic coating, wherein the crosslinked hydrophobic coating is changed into a smooth coating with certain toughness from a state of being easily scratched before crosslinking, and the thickness of the hydrophobic coating is obtained by characterization under a scanning electron microscope.

The corrosion test in Hank's solution was carried out in the same manner as in example 18, and the results showed that after 7 days of immersion, the pure iron wire having only a PLA coating on the surface thereof had been severely corroded and had broken at individual sites, whereas the pure iron wire having a hydrophobic coating on the surface thereof had not been corroded yet after 7 days of immersion, and remained in a radial strength comparable to that of the original state by 28 days.

Example 20

An absorbable iron-based coronary stent is prepared by the following steps: providing a 30008-sized pure iron matrix with a mass of 3.8mg, a wall thickness of 50 μm and an inner diameter of 1.45mm (the 30008 size is defined as follows: under the action of a nominal expansion pressure of 8atm (the nominal expansion pressure refers to the pressure used for expanding the stent to the nominal diameter), the expanded nominal diameter is 3.0mm, the nominal length is 8.0 mm. the 30008 size in the following examples represents the same meaning, and the description is not repeated, and polylactic acid-polydimethylsiloxane-polylactic acid (PLA) with a concentration of 0.02g/mL is prepared₁₅-PDMS₇₆-PLA₁₅-DA) macromonomer (i.e. hydrophobic monomer) in ethyl acetate solution, and adding photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 ‰ of the mass of the hydrophobic monomer. Spraying the mixed solution on all surfaces of the pure iron matrix by adopting an ultrasonic spraying method, ventilating to completely volatilize ethyl acetate, and forming uncrosslinked PLA on all surfaces of the pure iron matrix₁₅-PDMS₇₆-PLA₁₅-a DA coating. The flow rate of liquid supplied by the pump in the spraying process is 0.1mL/min, and the ultrasonic power is 4.75W. Then, the mixture was mixed at 365nm and 8000. mu.W/cm in intensity²Ultraviolet light of (2) on uncrosslinked PLA₁₅-PDMS₇₆-PLA₁₅Irradiating the DA coating for 30min to react the acryl groups in the coating to obtain a cross-linked hydrophobic coating, thereby forming a cross-linked hydrophobic coating covering the outer, inner and side surfaces of the pure iron matrix. The thickness of the hydrophobic coating was 8 μm, characterized under a scanning electron microscope.

Implanting the batches of absorbable iron-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. And (3) calculating iron weight loss by using micro-CT, wherein the iron is not corroded after 1 month after the implantation, the iron weight loss is 20% after 3 months after the implantation, and the iron weight loss is 40% after 6 months after the implantation.

Example 21

An absorbable iron-based coronary stent is prepared by the following steps: providing a 30008-specification pure iron matrix with the mass of 3.8mg, the wall thickness of 50 mu m and the inner diameter of 1.45mm, dissolving PLA with the molecular weight of 6 ten thousand in ethyl acetate, preparing a PLA solution with the concentration of 2mg/mL, spraying the PLA solution on the outer surface, the inner surface and the side surfaces of the pure iron matrix by adopting an ultrasonic spraying method, and forming PLA coatings with the thickness of 4 mu m on the outer surface, the inner surface and the side surfaces of the pure iron matrix after drying. Polytrimethylene carbonate-polydimethylsiloxane-polytrimethylene carbonate (PTMC) was formulated at a concentration of 0.02g/mL₂₀-PDMS₇₆-PTMC₂₀-DA) (i.e. hydrophobic monomer) in ethyl acetate, and adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per thousand of the mass of the hydrophobic monomer. Spraying the mixed solution on the outer surface, the inner surface and the side surface of the pure iron matrix by adopting an ultrasonic spraying method, ventilating to completely volatilize ethyl acetate, and forming non-crosslinked PTMC on the inner surface of the pure iron matrix₂₀-PDMS₇₆-PTMC₂₀-a DA coating. The flow rate of liquid supplied by the pump in the spraying process is 0.1mL/min, and the ultrasonic power is 4.75W. Then, the mixture was mixed at 365nm and 8000. mu.W/cm in intensity²Ultraviolet light of (2) on uncrosslinked PTMC₂₀-PDMS₇₆-PTMC₂₀Irradiating the DA coating for 2h to react the acryloyl groups in the coating to obtain a cross-linked hydrophobic coating, thereby forming a cross-linked hydrophobic coating covering the outer surface, inner surface and sides of the pure iron matrix. The thickness of the hydrophobic coating was 5 μm, characterized under a scanning electron microscope.

Implanting the batches of absorbable iron-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. And (3) calculating iron weight loss by using micro-CT, wherein iron is not corroded after the implantation for 1 month, iron is not corroded after the implantation for 3 months, and the iron weight loss is 50% after the implantation for 6 months.

Example 22

An absorbable iron-based coronary stent is prepared by the following steps: providing a 30008-specification nitrided iron matrix with the mass of 3.8mg, the wall thickness of 50 microns and the inner diameter of 1.45mm, dissolving PLA with the molecular weight of 6 ten thousand in ethyl acetate, preparing a PLA solution with the concentration of 2mg/mL, spraying the PLA solution on the outer surface, the inner surface and the side surfaces of the nitrided iron matrix by adopting an ultrasonic spraying method, and forming PLA coatings with the thickness of 4 microns on the outer surface, the inner surface and the side surfaces of the nitrided iron matrix after drying.

And (3) treating the nitrided iron matrix with the PLA coating on the surface under oxygen plasma, wherein the gas pressure is 50Pa, the plasma power is 100W, and the treatment time is 30 min. Sucking 50 μ L KH-570 silanized coupling agent with 100 μ L pipette, placing the gun head containing KH-570 and plasma treated pure magnesium substrate with PLA coating on the surface into a drier, vacuumizing, standing for 12 hr to volatilize KH-570 and adsorb on the PLA coating surface to form an adhesive layer on the PLA coating surface.

Synthesis of acryloyl-terminated polycaprolactone-polydimethylsiloxane-Polycaprolactone (PCL) in substantially the same manner as in example 1₁₀-PDMS₇₆-PCL₁₀-DA) macromonomers (i.e. hydrophobic monomers).

The polycaprolactone-polydimethylsiloxane-Polycaprolactone (PCL) with the concentration of 0.02g/mL is prepared₁₀-PDMS₇₆-PCL₁₀-DA) macromonomer (i.e. hydrophobic monomer) in ethyl acetate solution, and adding photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 ‰ of the mass of the hydrophobic monomer. Spraying the mixed solution on all surfaces of the nitrided iron matrix by an ultrasonic spraying method, ventilating to completely volatilize ethyl acetate, and forming an uncrosslinked PCL (PCL) covering adhesive layer on all surfaces of the pure iron matrix₁₀-PDMS₇₆-PCL₁₀-DA) coating. The flow rate of liquid supplied by the pump in the spraying process is 0.1mL/min, and the ultrasonic power is 4.75W. Then, the mixture was mixed at 365nm and 8000. mu.W/cm in intensity²Ultraviolet light on uncrosslinked (PCL)₁₀-PDMS₇₆-PCL₁₀DA) irradiating the coating for 1h to react the acryl groups in the coating to obtain a cross-linked hydrophobic coating, thereby forming a coating covering the pure iron matrixA cross-linked hydrophobic coating of the outer surface, inner surface and sides. The thickness of the hydrophobic coating was 20 μm, characterized under a scanning electron microscope.

Implanting the batches of absorbable iron-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. And (3) calculating iron weight loss by using micro-CT, wherein iron is not corroded after the implantation for 1 month, iron is not corroded after the implantation for 3 months, and the iron weight loss is 55% after the implantation for 6 months.

Example 23

An absorbable zinc-based coronary stent is prepared by the following steps: providing a 30008-standard pure zinc matrix with the mass of 6mg, the wall thickness of 90 mu m and the inner diameter of 1.45mm, and preparing PLA with the concentration of 0.02g/mL₁₇-PDMS₇₆-PLA₁₇Adding a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone into an ethyl acetate solution of-DA (hydrophobic monomer) to obtain a mixed solution, wherein the mass of the photoinitiator is 1 per mill of that of the hydrophobic monomer. Spraying the mixed solution on the inner surface of the pure zinc matrix by an ultrasonic spraying method, ventilating to completely volatilize ethyl acetate, and forming uncrosslinked PLA on the surface of the pure zinc matrix₁₇-PDMS₇₆-PLA₁₇-a DA coating. The flow rate of liquid supplied by the pump in the spraying process is 0.1mL/min, and the ultrasonic power is 4.75W. Then, the mixture was mixed at 365nm and 8000. mu.W/cm in intensity²Ultraviolet light of (2) on uncrosslinked PLA₁₇-PDMS₇₆-PLA₁₇The DA coating is irradiated for 1h to react the acryl groups in the coating to obtain a cross-linked hydrophobic coating, thereby forming a hydrophobic coating covering the inner surface of the pure zinc matrix. The thickness of the hydrophobic coating was characterized by 15 μm under a scanning electron microscope.

Implanting a plurality of absorbable zinc-based coronary stents of the batch into abdominal aorta of a plurality of rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. The zinc weight loss is calculated by micro-CT, the zinc weight loss is 4% after 1 month of implantation, the zinc weight loss is 25% after 3 months of implantation, and the zinc weight loss is 70% after 6 months of implantation.

Example 24

An absorbable magnesium-based coronary stent is prepared by the following steps: a30008-sized pure magnesium substrate having a mass of 2mg, a wall thickness of 100 μm and an inner diameter of 1.45mm was provided.

The polylactic acid-polydimethylsiloxane-polylactic acid (PLA) with the concentration of 0.02g/mL is prepared₁₅-PDMS₇₆-PLA₁₅-DA) macromonomer (i.e. hydrophobic monomer) in ethyl acetate solution, and adding photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone to obtain a mixed solution, wherein the mass of the photoinitiator is 1 ‰ of the mass of the hydrophobic monomer. Spraying the mixed solution on the surface of a magnesium substrate by ultrasonic spraying, wherein the flow rate of liquid supplied by a pump is 0.1mL/min, the ultrasonic power is 4.5W, and spraying is repeated for five times according to the parameter to form uncrosslinked PLA on the surface of the bonding layer of the pure magnesium substrate₁₅-PDMS₇₆-PLA₁₅-a DA coating.

Using 365nm, intensity of 10000 uW/cm²Ultraviolet light of (2) on uncrosslinked PLA₁₅-PDMS₇₆-PLA₁₅Irradiation of the DA coating for 1.5h to PLA₁₅-PDMS₇₆-PLA₁₅The terminal acryl groups of the DA are crosslinked to form a hydrophobic coating covering the outer, inner and side surfaces of the pure magnesium matrix. PLA can be found after illumination₁₅-PDMS₇₆-PLA₁₅The DA coating is changed from the original sticky-hand state to a smooth rubbery state with certain elasticity and toughness, and the thickness of the hydrophobic coating is 20 μm by characterization under a scanning electron microscope.

Implanting the batches of absorbable magnesium-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. And (3) calculating the magnesium weight loss by using micro-CT, wherein the magnesium is not corroded after 2 months of implantation, the magnesium weight loss is 40% after 3 months of implantation, and the magnesium weight loss is 100% after 6 months of implantation.

Comparative example 1

An absorbable iron-based coronary stent is made of pure iron, the specification of which is 30008, the mass of the absorbable iron-based coronary stent is 3.8mg, the wall thickness of the absorbable iron-based coronary stent is 50 mu m, and the inner diameter of the absorbable iron-based coronary stent is 1.45 mm.

Implanting the batches of absorbable iron-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. The iron weight loss is calculated by micro-CT, the iron weight loss is 8 percent (starts to degrade when contacting body fluid) after 1 month of implantation, the iron weight loss is 15 percent after 3 months of implantation, and the iron weight loss is 30 percent after 6 months of implantation.

The absorbable coronary iron-based stent of example 20 started to erode at a later time point compared to comparative example 1, but at a later stage of implantation, the erosion rate was significantly faster.

Comparative example 2

An absorbable iron-based coronary stent is prepared by the following steps: providing a 30008-specification pure iron matrix with the mass of 3.8mg, the wall thickness of 50 mu m and the inner diameter of 1.45mm, dissolving PLA with the molecular weight of 6 ten thousand in ethyl acetate, preparing a PLA solution with the concentration of 2mg/mL, spraying the PLA solution on the outer surface, the inner surface and the side surface of the nitrided iron matrix by adopting an ultrasonic spraying method, and forming a PLA coating with the thickness of 4 mu m on the outer surface, the inner surface and the side surface of the nitrided iron matrix after drying.

And respectively implanting a plurality of absorbable iron-based coronary stents of the batch into a plurality of rabbit abdominal aorta, wherein the over-expansion ratio is kept within the range of 1.1:1 to 1.2:1 in the implantation process. The iron weight loss was calculated using micro-CT, with 20% iron weight loss (starting to degrade upon contact with body fluid) 1 month after implantation, 40% iron weight loss 3 months after implantation and 50% iron weight loss 6 months after implantation.

The absorbable coronary iron-based stents of examples 21 and 22 initiated corrosion at a later time point compared to comparative example 2, but at a significantly faster corrosion rate later in the implantation.

Comparative example 3

An absorbable zinc-based coronary stent is made of pure zinc, the specification of the absorbable zinc-based coronary stent is 30008, the mass of the absorbable zinc-based coronary stent is 6mg, the wall thickness of the absorbable zinc-based coronary stent is 90 mu m, and the inner diameter of the absorbable zinc-based coronary stent is 1.45 mm.

Implanting the batches of absorbable zinc-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 in the implantation process. The zinc weight loss is calculated by micro-CT, the zinc weight loss is 12% after 1 month of implantation (degradation begins after contacting with body fluid), the zinc weight loss is 30% after 3 months of implantation, and the zinc weight loss is 60% after 6 months of implantation.

The time point for the initiation of corrosion was later for the absorbable zinc-based coronary stent of example 23 compared to comparative example 3, but the corrosion rate was significantly faster at the later stages of implantation.

Comparative example 4

An absorbable magnesium-based coronary stent is made of pure magnesium, has specification of 30008, mass of 2mg, wall thickness of 100 μm and inner diameter of 1.45 mm.

Implanting the batch of absorbable magnesium-based coronary stents into abdominal aorta of multiple rabbits respectively, wherein the over-expansion ratio is kept in the range of 1.1:1 to 1.2:1 during the implantation process. The magnesium weight loss is calculated by micro-CT, the magnesium weight loss is 30% after being implanted for 1 month (the magnesium starts to degrade when contacting body fluid), the magnesium weight loss is 80% after being implanted for 3 months, and the magnesium weight loss is 100% after being implanted for 4 months.

The time point for initiation of corrosion was later for the absorbable magnesium-based coronary stent of example 24 compared to comparative example 4, but the corrosion rate was significantly accelerated at the later stage of implantation.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A hydrophobic coating is covered on the surface of a degradable material and is characterized in that the hydrophobic coating is formed by crosslinking hydrophobic monomers,

wherein the hydrophobic monomer is a block copolymer comprising a hydrophobic block, a degradable block and a crosslinking functional group;

the degradable blocks are formed from degradable polymers,

the degradable polymer is at least one of polyglycolide, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly epsilon-caprolactone, poly epsilon-alkyl substituted caprolactone, poly delta-valerolactone or polyether ester;

or the degradable polymer is a copolymer formed by at least two of monomers forming polyglycolide, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly epsilon-caprolactone, poly epsilon-alkyl substituted caprolactone, poly delta-valerolactone or polyether ester.

2. A hydrophobic coating covers the surface of a degradable material, and is characterized in that the hydrophobic coating is a cross-linked coating formed by blending a hydrophobic monomer and a non-degradable component,

the degradable blocks are formed from degradable polymers,

the degradable polymer is at least one of polyglycolide, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly delta-valerolactone, polycarbonate or polyether ester;

or the degradable polymer is a copolymer formed by at least two of polyglycolide, poly L-lactide, poly D, L-lactide, polyhydroxybutyrate, poly delta-valerolactone, polycarbonate or polyether ester.

3. The hydrophobic coating of claim 1 or 2, wherein the hydrophobic block is formed from a hydrophobic polymer, the degradable block is formed from a degradable polymer, monomers of the hydrophobic block and monomers of the degradable block are polymerized to form the hydrophobic block and the degradable block which are connected by chemical bonds, and the crosslinking functional group is connected with the hydrophobic block and/or the degradable block by chemical bonds to crosslink the hydrophobic monomers to form the hydrophobic coating.

4. The hydrophobic coating of claim 1 or 2, wherein the hydrophobic block is formed from at least one of polydimethylsiloxane, perfluoropolyether, polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, or polyvinylidene fluoride-hexafluoropropylene copolymer.

5. The hydrophobic coating according to claim 1 or 2, wherein the degradable block has a molecular weight of 500 to 20000 and a degree of polymerization of 20 to 40.

6. A hydrophobic coating according to claim 1 or 2, wherein the cross-linking functional group is selected from at least one of allyl, acryl, methacryl, epoxy, oxazolinyl, cyanato, silicon hydroxy or siloxy.

7. The hydrophobic coating according to claim 2, wherein the non-degradable component is selected from at least one of silicone rubber, polysiloxane, polysilazane, or a fluoropolymer.

8. The hydrophobic coating of claim 1 or 2, wherein the hydrophobic coating has a thickness of 0.01 to 100 μm.

9. A method of preparing a hydrophobic coating according to claim 1 or 2, comprising:

providing a hydrophobic monomer, and applying triggering conditions to the hydrophobic monomer to enable the hydrophobic monomer to be crosslinked to form the hydrophobic coating; alternatively, a mixture of a hydrophobic monomer and a non-degradable component is provided, and conditions are applied to the mixture of the hydrophobic monomer and the non-degradable component to cause crosslinking of the non-degradable component or to cause crosslinking between the hydrophobic monomer and the non-degradable component to form the hydrophobic coating.

10. The method of claim 9, wherein the initiation condition is ultraviolet light irradiation, heat treatment or moisture action.

11. The method of claim 10, wherein the hydrophobic coating is selected from the group consisting of,

the ultraviolet light irradiation includes: mixing the hydrophobic monomer with a photoinitiator, and irradiating for 30 min-2 h by using 365nm ultraviolet light; the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-acetone, and the mass of the photoinitiator is 1 per mill of that of the hydrophobic monomer;

12. Use of a hydrophobic coating as claimed in claim 1 or 2 for retarding the degradation behaviour of a degradable material.

13. An absorbable implantable device, comprising an absorbable matrix, further comprising the hydrophobic coating of claim 1 or 2, covering the surface of the absorbable matrix.

14. The absorbable implantable device of claim 13, wherein said absorbable matrix material is a degradable polymer, a corrodible metal, or a composite of a corrodible metal and a degradable polymer.

15. The resorbable implantable device of claim 13, further comprising an adhesive layer between said resorbable substrate and said hydrophobic coating.

16. The absorbable implantable device of claim 15, wherein said adhesive layer comprises a material selected from at least one of dopamine and silane coupling agents.

17. The resorbable implantable device of claim 13, wherein said resorbable implantable device is a cardiovascular stent, a cerebrovascular stent, a peripheral vascular stent, a biliary stent, an esophageal stent, an airway stent, a urethral stent, an occluder, an orthopedic implant, or a resorbable suture.