Hydrophilic Coating Methods for Chemically Inert Substrates

Abstract

The present invention discloses methods for producing a hydrophilic coating for chemically inert substrates such as fluoropolymers using a multi-step coating process consisting of (1) producing a plasma polymerization coating of alcohol compounds on the substrate, followed by (2) sequentially contacting the plasma polymer coated substrate with one or more solutions of hydrophilic polymers. Advantageously, such methods produce a strongly adhered hydrophilic coating for fluoropolymer and other chemically inert substrates.

Claims

1. A method for producing a hydrophilic coating for a chemically inert substrate using a multi-step process consisting of (a) exposing said substrate to a plasma glow discharge in the presence of the vapor of at least one alcohol compound to produce a plasma polymer coated substrate; (b) contacting said plasma polymer coated substrate with a solution of hydrophilic polymers to produce a hydrophilic polymer coated substrate.

2. A method of claim 1, wherein said substrate contains fluoropolymers.

3. A method of claim 1, wherein said substrate contains fluoropolymers selected from the following list: polytetrafluoroethylene (PTFE), polyethylenetetrafluoroethylene (ETFE), fluorinated ethylene-propylene (FEP), perfluoroalkoxy polymer (PFA), polyethylenechlorotrifluoroethylene (ECTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinylfluoride (PVF), perfluorinated elastomer, fluoroelastomer, chlorotrifluoroethylenevinylidene fluoride, perfluoropolyether, perfluorosulfonic acid, and perfluoropolyoxetane.

4. A method of claim 1, wherein said substrate contains polyether ether ketone (PEEK).

5. A method of claim 1, wherein said substrate contains silicone elastomers.

6. A method of claim 1, wherein said substrate contains Nylon.

7. A method of claim 1, wherein said substrate contains polyether block amides (PEBAX).

8. A method of claim 1, wherein said substrate contains metals.

9. A method of claim 1, wherein said multi-step process further consists of sequentially contacting said hydrophilic polymer coated substrate with one or more solvents or solutions of hydrophilic polymers to produce a multi-layer hydrophilic polymer coated substrate.

10. A method of claim 9, wherein said multi-layer hydrophilic polymer contain covalent linkage between layers of hydrophilic polymers.

11. A method of claim 1, wherein said alcohol compound is selected from methanol, ethanol, isopropanol, butanol, and pentanol.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0013] FIG. 1 is a drawing representing a chemically inert substrate coated using subject invention multi-step coating method comprising of a plasma polymerization coating step and a hydrophilic polymer coating step.

DETAILED DESCRIPTION OF THE INVENTION

[0014] With reference to FIG. 1, a chemically inert substrate is first coated with plasma polymerization of alcohol compounds, and then the plasma polymer coated substrate is coated with a layer of hydrophilic polymer.

[0015] Any known technique can be used to generate the plasma glow discharge for plasma polymerization coating. The plasma may be generated using AC or DC power, radio-frequency (RF) power or micro-wave frequency power. Preferably, the plasma system is driven by a single radio-frequency (RF) power supply; typically at 13.56 MHz. The plasma system can either be capacitively coupled plasma, or inductively coupled plasma.

[0016] In a preferred embodiment, the monomer used for plasma polymerization is selected from methanol, ethanol, isopropanol, butanol, and pentanol. In the plasma state, the alcohol compounds are ionized and react with the surface of the substrate, forming a covalently bound thin film containing hydroxyl groups.

[0017] Any known technique can be used to produce the hydrophilic coating on top of the plasma polymer coating. The coating may be performed using dip coating, soak coating or spray coating. One or more solutions can be used to produce the hydrophilic coating with one or more layers of hydrophilic polymer. Each solutions may contain a mixture of polymers. After the application of each solution, the substrates may be rinsed with water or an organic solvent.

EXAMPLES

Example 1

[0018] PTFE substrates (squares, 1 inch by 1 inch) were coated in a radiofrequency plasma glow discharge chamber in the presence of vapors of isopropanol. The chamber was first pumped down to a pressure below 0.04 Torr. The vapor of isopropanol was introduced into the chamber and the pressure is adjusted to 0.2 Torr. A radiofrequency power of approximately 100 W was applied for 20 minutes to generate the plasma polymer coating.

Example 2

[0019] PTFE substrates coated with plasma polymer in Example 1 was dipped in a solution of 5% (w/v) polyvinylpyrrolidone (PVP) in 90% ethanol for 5 seconds, then dried at room temperature in air. As a control, PTFE substrates which have not been coated with plasma polymer were coated with PVP in the same way. The PTFE substrates coated with plasma polymer followed by PVP was found to be hydrophilic and lubricious. The PTFE substrates coated with PVP directly without plasma polymer was found to have no coating adhering to the substrate. The coated substrates were rinsed with water extensively, dried and characterized by Sessile drop contact angle measurements. The results are summarized in the Table below:

TABLE-US-00001 Water Contact PTFE substrates Angle Control 1: Uncoated 110 5 Control 2: attempted coating with PVP 110 5 without plasma polymer (Example 2 control) Current invention: coated with plasma 35 5 polymer, then PVP (Example 2)

Example 3

[0020] PTFE substrates coated with plasma polymerization in Example 1 was soaked in a solution of 1% (w/v) polyethylenimine (PEI) for 1 hour, rinsed with water, then soaked in a solution of 1% (w/v) oxidized dextran for 1 hour, and finally rinsed with water. As a control, PTFE substrates which have not been coated with plasma polymerization were coated with PEI and dextran in the same way. The coated substrates were rinsed with water extensively, dried and characterized by Sessile drop contact angle measurements. The results are summarized in the Table below:

TABLE-US-00002 Water Contact PTFE substrates Angle Control 1: Uncoated 110 5 Control 2: Attempted coating with PEI/dextran 65 5 without plasma polymer (Example 3 control) Current invention: coated with plasma <20 polymer, then PEI and dextran (Example 3)

Example 4

[0021] PEEK substrates (squares, 1 inch by 1 inch) were coated in a radiofrequency plasma glow discharge chamber in the presence of vapors of isopropanol. The chamber was first pumped down to a pressure below 0.04 Torr. The vapor of isopropanol was introduced into the chamber and the pressure is adjusted to 0.2 Torr. A radiofrequency power of approximately 100 W was applied for 20 minutes to generate the plasma polymer coating.

Example 5

[0022] PEEK substrates coated with plasma polymer in Example 4 was dipped in a solution of 5% (w/v) polyvinylpyrrolidone (PVP) in 90% ethanol for 5 seconds, then dried at room temperature in air. As a control, PEEK substrates which have not been coated with plasma polymer were coated with PVP in the same way. The PEEK substrates coated with plasma polymer followed by PVP was found to be hydrophilic and lubricious. The PEEK substrates coated with PVP directly without plasma polymer was found to have no coating adhering to the substrate.

Example 6

[0023] Silicone elastomer substrates (squares, 1 inch by 1 inch) were coated in a radiofrequency plasma glow discharge chamber in the presence of vapors of isopropanol. The chamber was first pumped down to a pressure below 0.04 Torr. The vapor of isopropanol was introduced into the chamber and the pressure is adjusted to 0.2 Torr. A radiofrequency power of approximately 100 W was applied for 20 minutes to generate the plasma polymer coating.

Example 7

[0024] Silicone elastomer substrates coated with plasma polymerization in Example 6 was soaked in a solution of 1% (w/v) polyethylenimine (PEI) for 1 hour, rinsed with water, then soaked in a solution of 1% (w/v) oxidized dextran for 1 hour, and finally rinsed with water. As a control, silicone elastomer substrates which have not been coated with plasma polymerization were coated with PEI and dextran in the same way. The coated substrates were rinsed with water extensively, dried and characterized by Sessile drop contact angle measurements. The results are summarized in the Table below:

TABLE-US-00003 Water Contact Silicone elastomer substrates Angle Control 1: Uncoated 110 5 Control 2: Attempted coating with PEI/dextran 70 5 without plasma polymer (Example 7 control) Current invention: coated with plasma <20 polymer, then PEI and dextran (Example 7)

Example 8

[0025] Nylon substrates (squares, 1 inch by 1 inch) were coated in a radiofrequency plasma glow discharge chamber in the presence of vapors of isopropanol. The chamber was first pumped down to a pressure below 0.04 Torr. The vapor of isopropanol was introduced into the chamber and the pressure is adjusted to 0.2 Torr. A radiofrequency power of approximately 100 W was applied for 20 minutes to generate the plasma polymer coating.

Example 9

[0026] Nylon substrates coated with plasma polymerization in Example 8 was soaked in a solution of 1% (w/v) polyethylenimine (PEI) for 1 hour, rinsed with water, then soaked in a solution of 1% (w/v) oxidized dextran for 1 hour, and finally rinsed with water. As a control, Nylon substrates which have not been coated with plasma polymerization were coated with PEI and dextran in the same way. The coated substrates were rinsed with water extensively, dried and characterized by Sessile drop contact angle measurements. The results are summarized in the Table below:

TABLE-US-00004 Water Contact Nylon substrates Angle Control 1: Uncoated 70 5 Control 2: Attempted coating with PEI/dextran 40 5 without plasma polymer (Example 9 control) Current invention: coated with plasma <20 polymer, then PEI and dextran (Example 9)

Example 10

[0027] PEBAX substrates (squares, 1 inch by 1 inch) were coated in a radiofrequency plasma glow discharge chamber in the presence of vapors of isopropanol. The chamber was first pumped down to a pressure below 0.04 Torr. The vapor of isopropanol was introduced into the chamber and the pressure is adjusted to 0.2 Torr. A radiofrequency power of approximately 100 W was applied for 20 minutes to generate the plasma polymer coating.

Example 11

[0028] PEBAX substrates coated with plasma polymer in Example 10 was dipped in a solution of 5% (w/v) polyvinylpyrrolidone (PVP) in 90% ethanol for 5 seconds, then dried at room temperature in air. As a control, PEBAX substrates which have not been coated with plasma polymer were coated with PVP in the same way. The PEBAX substrates coated with plasma polymer followed by PVP was found to be hydrophilic and lubricious. The PEBAX substrates coated with PVP directly without plasma polymer was found to have no coating adhering to the substrate.

Example 12

[0029] Stainless steel substrates (squares, 1 inch by 1 inch) were coated in a radiofrequency plasma glow discharge chamber in the presence of vapors of isopropanol. The chamber was first pumped down to a pressure below 0.04 Torr. The vapor of isopropanol was introduced into the chamber and the pressure is adjusted to 0.2 Torr. A radiofrequency power of approximately 100 W was applied for 20 minutes to generate the plasma polymer coating.

Example 13

[0030] Stainless steel substrates coated with plasma polymer in Example 12 was dipped in a solution of 5% (w/v) polyvinylpyrrolidone (PVP) in 90% ethanol for 5 seconds, then dried at room temperature in air. As a control, stainless steel substrates which have not been coated with plasma polymer were coated with PVP in the same way. The stainless steel substrates coated with plasma polymer followed by PVP was found to be hydrophilic and lubricious. The stainless steel substrates coated with PVP directly without plasma polymer was found to have no coating adhering to the substrate.

[0031] As will be appreciated by those skilled in the art, the subject invention can be used to produce a hydrophilic coating on chemically inert substrates. By way of non-limiting example, the subject invention can be used to coat medical devices such as catheter or guidewires that is made of or contains chemically inert polymers to increase hydrophilicity and lubricity.