Radiopaque coatings for polymer substrates
Improved radiopaque coatings particularly suitable for polymer substrates are described. A modified ion plasma deposition (IPD) method is used to provide coatings with macroparticle-dense surfaces that have excellent radiopacity. The coatings are particularly adapted to polymer surfaces because of high adherence and resistance to peeling and flaking.
1 . An ion plasma deposition (IPD) method for depositing a radiopaque coating on a polymer substrate, comprising:
depositing a first substantially macroparticle-free coating on a polymer substrate;
depositing a second macrodense macroparticle coating over the first coating;
forming a coating to a thickness between about 1 micron to about 100 microns;
wherein arc speed or distance of the substrate surface from the IPD target controls macroparticle production and density.
2 . The method of claim 1 wherein the first and second coatings are formed continuously without interruption of the deposition.
3 . The method of claim 2 wherein macroparticle density increases in the deposited coating relative to variation of arc speed or substrate surface distance from the IPD target.
4 . The method of claim 1 wherein the substantially macroparticle-free first layer is distinctly delineated from the densely distributed macroparticle second layer.
5 . The method of claim 1 wherein the densely distributed macroparticle layer comprises about 90,000/cm 2 macroparticles 1 micron or larger in size.
6 . The method of claim 1 wherein the plastic substrate is PTFE, ePTFE, polypropylene, polyester, PEEK, UHMWPE, silocone, polyimide or ABS.
7 . The method of claim 1 wherein the substrate is polyimide or PEEK.
8 . The method of claim 1 wherein the substrate is a medical device selected from the group consisting of valves, implants, catheters, stents and tubes.
9 . The method of claim 7 wherein the substrate is a PEEK spinal implant.
10 . The method of claim 1 wherein the substrate is a catheter.
11 . The method of claim 1 wherein the radiopaque coating is gold, titanium, niobium, molybdum or hafnium.
12 . The method of claim 11 wherein the radiopaque coating is gold or titanium.
13 . The method of claim 11 wherein the radiopaque coating is gold.
14 . The method of claim 11 wherein the gold is deposited at a thickness of 1, 5, 10, 15 or 20 microns.
15 . The method of claim 14 wherein the gold is deposited at a thickness of 5 microns.
16 . A polymer substrate coated with a radiopaque film comprising a densely distributed macroparticulate film surface over a substantially macroparticle-free adherent base coating continuous with the film surface.
17 . The polymer substrate of claim 16 wherein the coating is between about 100 nm and about 1 micron thick.
18 . The polymer substrate of claim 16 wherein the substrate is a device used in medical applications selected from the group consisting of stents, catheters, valves, tubes and implants.