Composite material comprising layered hydrophilic coatings

1. A composite material comprising

a) a support member having a first major surface and a second major surface, a plurality of pores extending from said first major surface to said second major surface,

b) a first polymer layer which dumbly coats the walls of the pores of the support member, the first polymer layer having both hydrophobic and hydrophilic properties, and

c) a second polymer layer which durably coats the surface of the first polymer layer, the second polymer being more hydrophilic than the first polymer layer, wherein the first polymer layer comprises a gel polymer.

2. A composite material according to claim 1 , wherein the gel polymer is substantially water-insoluble but water swellable.

3. A composite material according to claim 1 , wherein the gel polymer has an affinity parameter d 0 (H 2 O) of from about 12 to about 40.

4. A composite material according to claim 1 , wherein the gel polymer has an affinity parameter d 0 (H 2 O) of from about 12 to about 25.

5. A composite material according to claim 1 , wherein the first polymer layer comprises a non-crosslinked polymer.

6. A composite material according to claim 1 , wherein the first polymer layer comprises a crosslinked polymer.

7. A composite material according to claim 1 , wherein the gel polymer is a cellulose derivative, a polyester, a polyamide, a polyacrylate, poly(ethylene-co-vinyl alcohol) (EVAL), poly(ethylene-co-allyl alcohol), polyhydroxystyrene (poly(4-vinylphenol), poly(vinyl alcohol) 40% hydrolyzed (Mowiol 40-88), a partially charged polymer, a copolymer of neutral and charged monomers or a random copolymer of hydrophilic and hydrophobic monomers.

8. A composite material according to claim 7 , wherein the gel polymer is a cellulose derivative selected from the group consisting of cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, 2-hydroxyethyl cellulose and ethyl cellulose.

9. A composite material according to claim 8 , wherein the gel polymer is cellulose acetate having a degree of acetylation of from about 29 to about 61%.

10. A composite material according to claim 7 , wherein the gel polymer is a polyester selected from the group consisting of poly(ethylene adipate), polyethylene glycol terephthalate, poly(L-lactide), poly(DL-lactide) and poly(DL-lactide-co-glycolide).

11. A composite material according to claim 7 , wherein the gel polymer is a polyamide selected from the group consisting of poly(hexamethyleneadipamide) (Nylon 6/6) and poly(hexamethylenesebacamide) (Nylon 6/10).

12. A composite material according to claim 8 , wherein the gel polymer is a polyacrylate selected from the group consisting of poly(2-hydroxyethyl methacrylate) and poly(2-hydroxypropyl methacrylate).

13. A composite material according to claim 7 , wherein the gel polymer is poly(ethylene-co-vinyl alcohol) having an ethylene content of from about 27 to about 44 mol-%.

14. A composite material according to claim 7 , wherein the gel polymer is a partially charged polymer selected from the group consisting of sulfonated poly(ether-ether-ketone) (S-PEEK; <86% sulfonation), sulfonated poly(phenylene oxide) (S-PPO; <70% sulfonation), sulfonated polysulfone (S-PS; <70% sulfonation), sulfonated poly(ether sutfone)(SPES; <70% sulfonation), sulfonated polystyrene (SPSt <70% sulfonation), aminated polysulfone (<70% amination), aminated poly(phenylene oxide) (Q-PPO; <70% amination), aminated poly(vinylbenzyl chloride) (APVB; <70% amination), partially protonated or alkylated poly(4-vinylpyridine) (Q-P4VP; <30% protonation or alkylation).

15. A composite material according to claim 14 , wherein the gel polymer is a sulfonated poly(phenylene oxide).

16. A composite material according to claim 7 , wherein the gel polymer is a copolymer of neutral and charged monomers that is a poly(ethylene-co-acrylic acid) copolymer.

17. A composite material according to claim 7 , wherein the gel polymer is a random copolymer of one or more hydrophiic monomers and one or more hydrophobic monomers.

18. A composite material according to claim 17 , wherein the one or more hydrophobic monomers are selected from the group consisting of n-hexyl acrylate, n-heptyl methacrylate, 1-hexadecyl methacrylate, methyl methacrylate, styrene, 2,3, or 4-methylstyrene, n-myristyl acrylate, N-tert-butylacrylamide, N-(n-octadecyl)acrylamide, N-tert-octylacrylamide, n-octyl methacrylate, n-propyl aerylate, iso-propyl methacrylate, n-propyl methacrylate, stearyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, undecyl acrylate, undecyl methacrylate, vinyl butyrate, vinyl laurate, vinyl octadecylether, vinyl iso-octyl ether, vinyl stearate, tert-amyl methacrylate, N-benzylmethacrylamide, iso, sec, tert or n-butyl(meth)acrylate, N-cyclohexylacrylamide, cyclohexyl (meth)acrylate, n- or iso-decyl (meth)acrylate, di(n-butyl) itaconate, N-diphenylmethylacrylamide, N-dodecylmethacrylamide, n-dodecyl methacrylate, 2-ethylbutyl methacrylate, 2-ethylhexyl acrylate, N-ethylmethacrylamide, isooctyl acrylate, isotridecylacrylate, and isobornyl acrylate.

19. A composite material according to claim 17 , wherein the one or more hydrophilic monomers comprise negatively charged monomers.

20. A composite material according to claim 19 , wherein the one or more hydrophilic monomers comprise negatively charged monomers selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, sodium sulfnonate, vinylsulfonic acid, acrylamidoglycolic acid, methacrylic acid, acrylic acid, itaconic acid, 2-propene-s-sulfonic acid, sodium acrylate,2-sulfonethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, vinylbenzoic acid, vinylsulfonic acid, and 2-carboxyethyl acrylate.

21. A composite material according to claim 17 , wherein the one or more hydrophilic monomers comprise positively charged monomers.

22. A composite material according to claim 21 , wherein the one or more hydrophilic monomers comprise positively charged monomers selected from the group consisting of methacrylamidopropyltrimethylammonium chloride (MAPTAC),acrylamidopropyltrimethylammonium chloride (APTAC), 2-methacryloxyethyltrimethylammonium chloride, methacryloylcholine methyl sulphate, 2-N-morpholinoethyl acrylate, 2-N-morpholinoethyl methacrylate, 1-vinylimidazole, 2, or 4-vinylpyridine, 2-acryloxyethyltrimethylammonium chloride, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, 2-(tert -butylamino)ethyl methacrylate, diallylamine, diallyldimethylammonium chloride, 2-(N,N-diethylamino)ethyl methacrylate, 2-(diethylamino)ethylstyrene, 2-(N,N-dimethylamino)ethyl acrylate, N-[2-(N,N-dimethylamino) ethyl]methacrylamide, 2-(N,N-dimethylamino)ethyl methacrylate, and N-[3-(N,N-dimethylamino)propyl](meth)acrylamide.

23. A composite material according to claim 17 , wherein the one or more hydrophilic monomers comprise neutral monomers.

24. A composite material according to claim 23 , wherein the one or more hydrophilic monomers comprise neutral monomers selected from the group consisting of 4-hydroxybutyl methacrylate, 2-hydroxylethyl (meth)acrylate, N-(2-hydroxypropyl)methacrylamide, hydroxypropyl (meth)acrylate, (meth)acrylamide, N-methacryloylmorpholine, N-methylmethacrylamide, N-methylacrylamide, monoacryloxyethyl phosphate, 1,1,1-trimethylolpropane diallyl ether, 1,1,1-trimethylolpropane mono allyl ether, poly(ethylene glycol) monomethacrylate, poly(propylene glycol)monomethacrylate, N-isopropylacrylamide, N-vinylcaprolactam, N-vinylformamide, vinyl-4-hydroxybutylether, N-vinyl-N-methacetamide, vinyl methylsulfone, N-vinyl- 2-pyrrolidone, N-vinylurea, acrylamide, N-acryloylmorpholine, N-acryloyltri(hydroxymethyl)methylamine, diethylacrylamide, N,N-diethylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, glycerol monoacrylate, glycerol monomethacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, and tetrahydrofurfuryl acrylate.

25. A composite material according to claim 17 , wherein the random copolymer further comprises one or more reactive monomers.

26. A composite material according to claim 25 , wherein the one or more reactive monomers are selected from the group consisting of methacrylic anhydride, vinyl azlactone, acrylic anhydride, allyl glycidyl ether, allylsuccinic anhydride, 2-cinnamoyloxyethyl acrylate, cinnamyl methacrylate, citraconic anhydride, and glycidyl acrylate.

27. A composite material according to claim 17 , wherein the random copolymer of hydrophilic and hydrophobic monomers is selected from the group consisting of poly(2-acrylamido-2-methylpropanesulfonic acid-co-N-t-butylacrylamide), poly (N-vinylformamide-co-N-t-butylacrylamide), poly(2-acrylamidopropane-trimethyl ammonium chloride-co-N-t-butylacrylamide), poly(methacrylamidopropane-trimethylammonium chloride-co-N-t-butylacrylamide), poly(2-acrylamido-2-methylpropanesulfonic acid -co-methylmethacylate) poly(N-vinylformamide-co-co-methylmethacylate), poly(2-acrylamidopropane-trimethyl ammonium chloride-co-methylmethacylate) and poly(methacrylamidopropane-trimethylammonium chloride-co-methylmethacylate).

28. A composite material according to claim 1 , wherein the second polymer layer comprises a crosslinked gel polymer.

29. A composite material according to claim 1 , wherein the second polymer layer comprises a monomer or polymer selected from the group consisting of ethyleneimine, 4-styrenesulfonic acid, vinyl alcohol, acrylic acid, diallyldimethylammonium chloride, acrylamide and vinylpyrrolidone, 2-acryloxyethyltrimethylammonium chloride, N-acryloyltris(hydroxymethyl)methylamine, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, N,N-diethylacrylamide, N,N-dimethylacrylamide, 2-(N,N-dimethylamino)ethyl acrylate and methacrylate, N-[3-(N,N-dimethylamino)propyl]methacrylamide, N,N-dimethylacrylamide, n-dodecyl acrylate, n-dodecyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate and methacrylate, 2,3-dihydroxypropyl acrylate and methacrylate, glycidyl acrylate and methacrylate, n-heptyl acrylate and methacrylate, 1-hexadecyl acrylate and methacrylate, 2-hydroxyethyl acrylate and methacrylate, N-(2-hydroxypropyl)methacrylamide, hydroxypropyl acrylate and methacrylate, methacrylamide, methacrylic anhydride, methacryloxyethyltrimethylammonium chloride, 2-(2-methoxy)ethyl acrylate and methacrylate, N-iso-propylacrylamide, 4-vinylpyridine, vinylsulfonic acid, N-vinyl-2-pyrrolidone,poly(ethyleneimine) (PEI), poly(4-styrenesulfonic acid), poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), poly(diallyldimethylammonium chloride) (PDADMAC), polyacrylamide (PAcAm) and polyvinylpyrrolidone (PVPR).

30. A composite material according to claim 1 , wherein the second polymer layer is covalently bonded to the first polymer layer.

31. A composite material according to claim 1 , wherein the polymer forming the first layer has a molecular weight of from about 5,000 to about 500,000 g/mol.

32. A composite material according to claim 1 , wherein the polymer forming the second polymer layer has a molecular weight of from about 5,000 to about 500,000 g/mol.

33. A composite material according to claim 1 , wherein the support member has pores having an average pore size of from 0.1 to 30 μm, and a volume porosity of from 60 to 90%.

34. A composite material according to claim 1 , wherein the support member is in the form of a flat sheet, a hollow tube fibre, or a tubular membrane.

35. A composite material according to claim 1 , wherein the support member is in the form of a flat sheet having a thickness of from 10 to 1000 μm.

36. A composite material according to claim 1 , comprising at least one additional polymer layer, each additional layer durably coating a previously deposited polymer layer.