Hydrophilic coating

1. A coating formulation for preparing a hydrophilic coating, wherein the hydrophilic coating formulation comprises

(a) a supporting oligomer, prepolymer and/or polymer comprising at least 2 reactive moieties capable of undergoing polymerization reactions; wherein the supporting oligomer, prepolymer or polymer has a number average molecular weight in the range 750-20,000 g/mol;

(b) a polyelectrolyte;

(c) a Norrish Type I photoinitiator; and

(d) a Norrish Type II photoinitiator.

2. The coating formulation according to claim 1 , wherein the Norrish Type I photoinitiator is at least one selected from the group consisting of benzoin derivatives, methylolbenzoin, 4-benzoyl-1,3-dioxolane derivatives, benzilketals, α,α-dialkoxyacetophenones, α-hydroxy alkylphenones, α-aminoalkylphenones, acylphosphine oxides, bisacylphosphine oxides, acylphosphine sulphides, and halogenated acetophenone derivatives.

3. The coating formulation according to claim 1 , wherein the Norrish Type II photoinitiator is at least one aromatic ketone selected from the group consisting of benzophenone, xanthone, chlorobenzophenone), 4-methyl-benzophenone, Michler's Ketone, Ethyl Michler's Ketone, thioxanthone, isopropyl thioxanthone, benzil, anthraquinones, coumarin, and chemical derivatives or combinations thereof.

4. The coating formulation according to claim 1 , wherein the supporting polymer comprises a backbone selected from the group consisting of polyethers, polythioethers, polyurethanes, polyethylenes, polypropylenes, polyvinyl chlorides, polyepoxides, polyamides, polyacrylamides, poly(meth)acrylics, polyoxazolidones, polyvinyl alcohols, polyethylene imines, polyesters, polypeptides, polysaccharides and combinations thereof, and at least 2 reactive moieties selected from the group consisting of radically reactive groups, unsaturated esters, unsaturated ethers, unsaturated amides, and alkyd/dry resins.

5. The coating formulation according to claim 1 , wherein the polyelectrolyte is at least one selected from the group consisting of salts of homo- and co-polymers of acrylic acid, salts of homo- and co-polymers of methacrylic acid, salts of homo- and co-polymers of maleic acid, salts of homo- and co-polymers of fumaric acid, salts of homo- and co-polymers of sulfonic acid, quarternary ammonium salts, mixtures thereof and mixtures of derivatives thereof.

6. The coating formulation according to claim 5 , wherein the polyelectrolyte is a poly(acrylamide-co-acrylic acid) salt.

7. A hydrophilic coating obtain by curing a hydrophilic coating formulation according to claim 1 .

8. A lubricious coating obtain by applying a wetting fluid to a hydrophilic coating according to claim 7 .

9. A lubricious coating according to claim 8 , having a wear resitance, as measured according to a particulates release wear test, of less than 3000, particles larger than 10 μm.

10. A coating system for preparing a lubricious coating, said coating system comprising a coating formulation according to claim 1 and a wetting fluid.

11. An article comprising at least one hydrophilic coating according to claim 7 .

12. The article according to claim 11 , wherein the article is a medical device or component.

13. The article according to claim 12 , wherein the medical device or component comprises a catheter, a medical tubing, a guide wire, a stent, or a membrane.

14. The coating formulation of claim 4 wherein the supporting oligomer, prepolymer or polymer has a number average molecular weight in the range 1,000-15,000 g/mol.

15. The coating formulation of claim 4 wherein the supporting oligomer, prepolymer or polymer has a number average molecular weight in the range 1,100-10,000 g/mol.

16. The coating formulation of claim 4 wherein the supporting oligomer, prepolymer or polymer polymer has a number average molecular weight in the range 1,200-7,000 g/mol.

17. The coating formulation of claim 4 wherein the supporting oligomer, prepolymer or polymer has a number average molecular weight in the range 1,400-5,000 g/mol.

18. A method of forming on a substrate a hydrophilic coating, the method comprising

applying a coating formulation according to claim 1 to at least one surface of a substrate; and

allowing the coating formulation to cure by exposing the formulation to electromagnetic radiation thereby activating the initiator.