Coating compositions and related equipment and methods

Abstract

A method of treating a substrate, for example forming a coating on the substrate, is described. The method may include applying a solution containing a multifunctional molecule or a multifunctional polymer molecule to at least a portion of a surface of the substrate. The surface may comprise a metal or metal alloy, and the multifunctional molecule or the multifunctional polymer molecule may be attached to the surface via at least one sulfur group of a plurality of sulfur groups of the multifunctional molecule. The method may include combining the multifunctional molecule with a polymer molecule to form the multifunctional polymer molecule, either before or after applying the solution. The polymer molecule may be attached to an internal carbon group or a terminal sulfur group of the multifunctional molecule.

Description

[Technical field]

[0001] The present disclosure relates generally to coating compositions that may be applied to substrates, such as medical devices, including substrates that include metals and metal alloys. For example, the present disclosure includes compositions useful as coatings for devices and methods for treating substrates. [Background technology]

[0002] Medical devices may be subject to some degradation due to moisture or lack thereof, especially the metallic components of such devices. For example, fluids may cause corrosion of metal surfaces over time. Corrosion may lead to multiple medical device malfunctions. In other instances, excessive drying due to lack of moisture or lubrication may result in other forms of degradation, such as wear and / or spalling. Providing corrosion resistance and lubricity to medical devices may allow the use of less expensive metals / metal alloys, thereby reducing costs, and may also broaden the range of materials that may be used. Summary of the Invention

[0003] The disclosure includes, for example, a method of treating a substrate, the method comprising: applying a solution comprising a multifunctional molecule or a multifunctional polymer molecule to at least a portion of a surface of a substrate, the surface comprising a metal or metal alloy, the multifunctional molecule or the multifunctional polymer molecule being attached to the surface via at least one sulfur group of a plurality of sulfur groups of the multifunctional molecule; and, before or after applying the solution, combining the multifunctional molecule with a polymer molecule to form the multifunctional polymer molecule, the polymer molecule being attached to an internal carbon group or a terminal sulfur group of the multifunctional molecule, to form a coating in which the multifunctional polymer molecule is attached to at least a portion of the surface.

[0004] In at least one example, the multifunctional molecule or the multifunctional polymer molecule's sulfur groups include at least one thiadiazole or dithiazole group. In at least one other example, the multifunctional molecule includes 2,5-dimercapto-1,3,4-thiadiazole or a derivative thereof. In another example, applying the solution to the surface includes selective deposition or stamping techniques, thereby forming a textured surface. In at least one example, the polymer molecules are hydrophilic or hydrophobic, and the polymer molecules have terminal thiol or methanesulfonate groups. In at least one other example, the polymer molecules are bonded to the multifunctional molecule after applying the solution to the at least a portion of the surface.

[0005] According to some aspects herein, the method may further include preparing the solution by combining the polyfunctional molecule with a polar solvent and a deprotonation additive. In at least one example, the polyfunctional molecule has a polybutadiene chain. In at least one other example, the polymer molecule is bonded to an internal carbon of the polybutadiene chain of the polyfunctional molecule. In some examples, the polymer molecule may be bonded to the polyfunctional molecule prior to applying the solution to the at least a portion of the surface. Preparing the solution may include combining the polyfunctional molecule with a polar solvent, a deprotonation additive, and the polymer molecule, where the polymer molecule is bonded to a terminal sulfur group of the polyfunctional molecule. The deprotonation additive may be sodium hydroxide.

[0006] According to some aspects herein, the method may further include heating at least a portion of the surface to which the solution has been applied prior to bonding the polymer molecules to the multifunctional molecules. The method may further include treating the surface with plasma or heat prior to applying the solution to the at least a portion of the surface. In some examples, the substrate is a medical device.

[0007] The present disclosure also includes a substrate having a coating, the substrate comprising a metal or metal alloy, the coating comprising a multifunctional polymer molecule formed by bonding a multifunctional molecule to a polymer molecule, the multifunctional molecule having a plurality of sulfur groups, the polymer molecule being bonded to an internal carbon or terminal sulfur group of the multifunctional molecule, and at least one of the sulfur groups being bonded to a surface of the substrate. The multifunctional molecule may have at least one thiadiazole or dithiazole group. The multifunctional molecule may include, for example, 2,5-dimercapto-1,3,4-thiadiazole or a derivative thereof. In some examples, the polymer molecule is hydrophobic or hydrophilic.

[0008] The present disclosure also includes a medical device comprising a metal surface and a coating covering at least a portion of the metal surface, wherein the coating comprises a multifunctional polymer molecule formed by combining a multifunctional molecule with a polymer molecule, the multifunctional molecule comprising a plurality of sulfur groups, the polymer molecule being bonded to an internal carbon group or a terminal sulfur group of the multifunctional molecule, at least one sulfur group of the plurality of sulfur groups being bonded to the metal surface, and the coating is hydrophobic or hydrophilic. [Brief description of the drawings]

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the detailed description, serve to explain the principles of the disclosed embodiments. [Figure 1A] FIG. 1 is a perspective view of a medical device according to some aspects of the present disclosure. [Figure 1B] 1B is a cross-sectional view of a portion of the medical device of FIG. 1A. [Figure 1C] 1B is a cross-sectional view of a portion of the medical device of FIG. 1A. [Figure 1D] 1 is a cross-sectional view of a portion of a medical device according to some aspects of the present disclosure. [Figure 1E] 1 is a cross-sectional view of a portion of a medical device according to some aspects of the present disclosure. [Diagram 2] 1 is a scheme of substrate treatment according to embodiments of the present disclosure. [Diagram 3] 1 is a scheme of substrate treatment according to embodiments of the present disclosure. [Figure 4] 1 is a scheme of substrate treatment according to embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Both the general description above and the detailed description below are exemplary and explanatory only and are not intended to limit the claimed features. As used herein, the words "comprises," "comprising," "having," "including," or other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or device that includes the recited elements does not include only those elements, but may include other elements not expressly recited or inherent to such process, method, article, or device. In this disclosure, relative terms such as "about," "substantially," "generally," "approximately," etc., are used to indicate a variation of ±5% of a stated value or characteristic.

[0011] The embodiments of the present disclosure may address one or more technical limitations. However, the scope of the present disclosure is defined by the appended claims, not by the ability to solve a particular problem. The present disclosure includes coatings that may be applied to a variety of substrates having surfaces that include metals or metal alloys, and methods of applying the coatings. Exemplary substrates include medical devices such as guidewires, stents, drainage catheters, pacemaker leads, bone pins, staples, and other devices, including injection molding tools and extrusion dies. The present coatings impart desired properties or characteristics to the substrate based on the composition of the coating. Thus, some examples of the present coatings may be hydrophilic, e.g., suitable for environments where it is desirable to retain moisture on the substrate surface, and some other examples of the present coatings may be hydrophobic, e.g., suitable for environments where it is desirable to repel moisture to provide corrosion resistance. The present coatings may impart other properties, e.g., antibody detection, radiopacity, antifouling, antibacterial, contact kill antibacterial, etc.

[0012] The compositions of the present application may be applied to a substrate to provide a coating on at least a portion of the substrate, or may cover the entire surface of the substrate.

[0013] 1A-1E illustrate an exemplary substrate, such as a medical device 10. As shown in FIGURES 1A-1C, the device 10 includes a shaft 12, the shaft 12 includes a wall 122, which may include a metal or metal alloy, and the shaft 12 includes a coating 124 covering an entire surface of the wall 122. In some examples, the coating 124 may be applied to only a portion of the surface of the substrate, such as to portion(s) or cross-section(s) of the surface of the wall 122.

[0014] FIG. 1D, for example, illustrates another shaft 12′ of a medical device, the shaft 12′ comprising a coating 124′ applied to various portions of the wall 122′, such that certain regions of the shaft 12′ may be functionalized with desired properties imparted by the coating 124′, while other regions remain uncoated. FIG. 1E illustrates another example, illustrating a device having multiple different coatings. As shown, the device comprises a shaft 12″ comprising a first coating 124″ and a second coating 224″ applied to the same substrate, e.g., to the wall 122″ of the shaft 12″. Thus, for example, the region of the shaft 12″ comprising the first coating 124″ may have different properties than the region(s) of the shaft 12″ comprising the second coating 224″. For example, the first coating 124″ may be hydrophobic, while the second coating 224″ may be hydrophilic.

[0015] Thus, substrates according to the present disclosure may have different properties; for example, different portions or regions of the shaft 12'' may react differently to water depending on the presence or absence of a coating and the chemical characteristics of the coating. As noted above, the coatings of the present disclosure may impart desired properties other than hydrophilicity or hydrophobicity. The application of a coating or multiple different coatings may optionally be applied in a pattern. The coatings of the present disclosure may be applied via any suitable method, including, but not limited to, vapor deposition or stamping. Such techniques may be used to create a textured surface. In some examples, the coatings may be applied by an etching method.

[0016] Exemplary coatings according to aspects of the present disclosure (e.g., any of coatings 124, 124', 124'' or 224'') may include a multifunctional molecule attached to a polymer molecule. The multifunctional molecule may be organic and may have a plurality of sulfur groups. Exemplary sulfur groups may include, for example, thiol groups or disulfide groups. At least one of the plurality of sulfur groups may be covalently bonded to a surface of a substrate. For example, one or more sulfur groups of the multifunctional molecule may be bonded to a metal / metal alloy surface of the substrate.

[0017] In some examples, the multifunctional molecule may have at least one thiadiazole group and / or at least one dithiazole group. Some examples of the multifunctional molecule include 2,5-dimercapto-1,3,4-thiadiazole (DMcT), bisdimercaptothiadiazole ether (biDMcT ether), 5-epoxy-1,3,4-thiadiazole, 5-methyl-1,3,4-thiadiazole, and derivatives thereof. Without being bound by theory, the thiadiazole group may be advantageous due to the delocalization of electrons in the multifunctional molecule. For example, the five-membered ring structure of the thiadiazole group may facilitate easier coordination with metal atoms or complexes on the surface of a substrate.

[0018] As described above, while at least one sulfur group of the polyfunctional molecule may be attached to the substrate, the polyfunctional molecule may also be available to be attached to a polymer molecule, for example via its terminal sulfur group, internal sulfur group or internal carbon group, which may act as an anchor group to the substrate and may be further functionalized once attached to the polymer molecule.

[0019] When the polymer is bonded to a polyfunctional molecule, it can impart functionality to the polyfunctional molecule. Exemplary polymer molecules of the present disclosure include, but are not limited to, polyethers such as polyethylene glycol. In some examples, the polymer molecules can impart hydrophobicity to the coating. For example, hydrophobic polymer molecules can include silicone-based polymers, polytetrafluoroethylene (PTFE), 2-perfluorohexylethylthiol, polydimethylsiloxane (PDMS), and derivatives thereof. Additionally, examples of hydrophilic polymer molecules can include polyacrylates, polyethylene glycols (PEG), polyvinylpyrrolidones, polyoxazolines, polyvinyl alcohols (PVA), quaternary ammonium functionalized polymers, and derivatives thereof. In some examples, the polymer molecules can have terminal thiol groups that can be bonded to the polyfunctional molecule, or methanesulfonate groups that can function as leaving groups when the polymer molecules are bonded to the polyfunctional molecule. Other suitable polymer molecules may impart antibody detection, radiopacity, stain resistance, antibacterial properties, contact kill antibacterial properties, among other desired properties of the coating.

[0020] An exemplary method for applying the coating to a substrate is provided below.

[0021] In some examples, the substrate may be treated prior to applying a coating or as part of the coating process. For example, the method of the present disclosure includes optionally treating the surface of the substrate, applying a solution containing a polyfunctional molecule to at least a portion of the substrate surface (and optionally preparing the solution prior to application), and combining the polyfunctional molecule with the polymer molecule, e.g., binding the polyfunctional molecule to the polymer molecule. When treating the surface prior to applying a coating, the method of the present disclosure may include wiping the surface with a suitable cleaning agent (e.g., detergent), rinsing the surface (e.g., with water), drying the surface, and / or exposing the surface to plasma or heat. For example, plasma and / or heat may activate binding groups, e.g., hydroxy groups, on the substrate surface, thereby priming such groups for covalent bond formation with sulfur groups of the polyfunctional molecule. Such treatment may precede the step of applying a coating.

[0022] The solution includes at least the polyfunctional molecule and a suitable solvent. As further described below, in some cases, the solution may further include polymer molecules and / or one or more additives. The solution can be prepared by dissolving the polyfunctional molecule in a solvent. The solvent can be an organic solvent and / or a polar solvent capable of dissolving the polyfunctional molecule. Exemplary solvents include, but are not limited to, tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylsulfoxide (DMSO), chloroform, and dichloromethane. In some examples, the solution also includes a deprotonation additive, e.g., a molecule capable of deprotonating a sulfur group of the polyfunctional molecule. Thus, for example, the deprotonation additive can condition the polyfunctional molecule for binding to the substrate and / or the polymer molecule via the deprotonated sulfur group(s). Exemplary deprotonation additives suitable for the present disclosure include, but are not limited to, sodium hydroxide (NaOH), potassium hydroxide (KOH), potassium tert-butoxide (BuO- K + ) and sodium hydride (NaH). In some examples, the solution may include 1-99 wt % of the polyfunctional molecule and 1-99 wt % of the solvent. As described further below, the solution may include one or more additional additives, such as additives to further modify the polyfunctional molecule, initiators, etc. Preparation of the solution may optionally include heating the solution to aid in dissolving the polyfunctional molecule.

[0023] The solution may be applied by any suitable technique, such as dip-coating or spray-coating. For example, at least a portion of the substrate may be immersed in the solution. Upon contact with the substrate surface, the polyfunctional molecule may bond to a metal of the substrate via at least one sulfur group of the polyfunctional molecule. In some instances, the substrate covered with the solution may be heated, for example, in an oven or by blowing heated air, to prime the polyfunctional molecules on the substrate surface for bonding with the polymer molecules.

[0024] The multifunctional molecules may be attached to the polymer molecules before or after the solution is applied to the substrate. For example, the multifunctional molecules may be combined with the polymer molecules so that the molecular species can be attached together, for example, during the preparation of the solution. The solution containing the multifunctional polymer-attached molecules may then be subsequently applied to the substrate. In another example, the multifunctional molecules are first attached to the substrate surface, and then the polymer molecules are attached to the multifunctional molecules attached to the surface. The polymer molecules may be combined with the multifunctional molecules attached to the surface via a suitable technique, such as dip-coating or spray-coating, thereby applying the coating to the substrate.

[0025] As mentioned above, the polyfunctional molecule may be attached to the polymer molecule, for example, via a terminal sulfur group, an internal sulfur group, or an internal carbon group of the polyfunctional molecule. The bond formation between the polyfunctional molecule and the polymer molecule may include, for example, a radical-mediated thiol-ene click reaction, a reversible addition-fragmentation chain transfer polymerization, or a nitroxide-mediated polymerization.

[0026] An example of bond formation between methanesulfonyl-terminated polybutadiene as the polymer molecule and DMcT as the multifunctional molecule after DMcT is bonded to the surface of a substrate is shown in FIG.

[0027] For example, a first solution comprising DMcT, a solvent and sodium hydroxide may be applied to the substrate. The sodium hydroxide may act as a deprotonating agent for DMcT. Methanesulfonyl terminated polybutadiene may be prepared by combining methanesulfonyl chloride with hydroxy-terminated polybutadiene, for example in a suitable solvent, to react and form methanesulfonyl terminated polybutadiene. For example, a second solution may comprise methanesulfonyl terminated polybutadiene and a solvent that is the same or different from the first solution. The methanesulfonyl terminated polybutadiene is combined with the DMcT bound to the substrate surface (e.g., by applying the second solution to the substrate) to form a biDMcT ether, i.e., a DMcT-terminated polybutadiene ether bound to the substrate as shown in FIG. 2.

[0028] FIG. 3 shows another example, where polymer molecules are bonded to multifunctional molecules on a substrate surface to form a coating.

[0029] As shown in Figure 3, DMcT as a multifunctional molecule can be deprotonated by combining with sodium hydroxide, e.g., in a suitable solvent, to form sodium DMcT. This sodium DMcT can then be combined with a methanesulfonyl terminated polymer molecule, thereby resulting in bond formation between the terminal sulfur groups of the sodium DMcT and the polymer molecule. The resulting multifunctional polymer molecule, e.g., in solution, can then be applied to the substrate by a suitable technique, thereby bonding the multifunctional polymer molecule to the substrate, e.g., via the sulfur groups available for bond formation, as shown in Figure 3.

[0030] FIG. 4 shows another example, in which reversible addition-fragmentation chain transfer (RAFT) polymerization can be performed to form a coating. As shown in FIG. 4, DMcT can be combined with hydrogen peroxide, for example in solution, to react and form a DMcT dimer containing a disulfide bond. The DMcT dimer can be combined with carbon disulfide and azobisisobutyronitrile (AIBN), which can function as a radical initiator, to form a thiocarbonyl thioester-based disulfide. Sodium borohydride can be used as a reducing agent to form a terminal thiol-based thiocarbonyl thioester as an SH-based RAFT polymerization chain transfer agent. The resulting multifunctional molecule can be applied to a substrate surface, and then monomers can be supplied to couple to extend the polymer chain, thereby resulting in surface functionalization of the substrate.

[0031] It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification, drawings, and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated in the following claims.

Claims

1. 1. A method of treating a substrate, the method comprising: applying a solution comprising polyfunctional molecules or polyfunctional polymer molecules to at least a portion of a surface of the substrate, the surface comprising a metal or metal alloy, and the polyfunctional molecules or polyfunctional polymer molecules are bonded to the surface via at least one sulfur group of the polyfunctional molecules; combining the polyfunctional molecule with a polymer molecule, either before or after applying the solution, to form the polyfunctional polymer molecule, wherein the polymer molecule is bonded to an internal carbon group or a terminal sulfur group of the polyfunctional molecule; Including, the multifunctional polymer molecules form a coating attached to said at least a portion of said surface. method.

2. The method of claim 1 , wherein the plurality of sulfur groups of the polyfunctional molecule or the polyfunctional polymer molecule includes at least one thiadiazole or dithiazole group.

3. The method according to claim 1 or 2, wherein the polyfunctional molecule includes 2,5-dimercapto-1,3,4-thiadiazole or a derivative thereof.

4. The method of claim 1 or 2, wherein applying the solution to the surface comprises selective deposition or stamping, thereby forming a textured surface.

5. 3. The method of claim 1, wherein the polymer molecules are hydrophilic or hydrophobic, and the polymer molecules have terminal thiol groups or terminal methanesulfonate groups.

6. The method of claim 1 or 2, wherein after applying the solution to the at least a portion of the surface, the polymer molecules are bound to the multifunctional molecules.

7. 7. The method of claim 6, further comprising preparing the solution by combining the polyfunctional molecule with a polar solvent and a deprotonating additive.

8. The method of claim 6 , further comprising the step of heating at least a portion of the surface to which the solution has been applied prior to bonding the polymer molecules to the multifunctional molecules.

9. The method of claim 1 or 2, wherein the polyfunctional molecule comprises a polybutadiene chain.

10. 10. The method of claim 9, wherein the polymer molecules are bonded to interior carbons of the polybutadiene chains of the multifunctional molecule.

11. The method of claim 1 or 2, wherein the polymer molecules are attached to the multifunctional molecules prior to applying the solution to the at least a portion of the surface.

12. 12. The method of claim 11, wherein preparing the solution comprises combining the polyfunctional molecule with a polar solvent, a deprotonating additive, and the polymer molecule, wherein the polymer molecule is attached to a terminal sulfur group of the polyfunctional molecule.

13. 8. The method of claim 7, wherein the deprotonating additive is sodium hydroxide.

14. The method of claim 1 or 2, further comprising treating the surface with plasma or heat before applying the solution to the at least a portion of the surface.

15. The method of claim 1 or 2, wherein the substrate is a medical device.

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