Composite filtration membranes and methods of preparation thereof

1. A composition, comprising:

a crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones covalently linked to a bridging group, the backbones comprising i) respective first repeat units, each of which comprises a first side chain ester moiety comprising a hydrophilic poly(alkylene oxide) chain segment, ii) respective second repeat units, each of which comprises a second side chain ester moiety directly linked to the bridging group through a linking group selected from the group consisting of carbamate groups, and thiocarbamate groups, and iii) respective third repeat units, each of which comprises a hydrophobic side chain moiety not directly linked to any bridging group.

2. The composition of claim 1 , wherein the composition has anti-fouling and/or salt rejection properties suitable for fluid purification.

3. The composition of claim 1 , wherein each linking group is a carbamate group.

4. The composition of claim 1 , wherein the bridging group is selected from the group consisting of

and

combinations thereof, wherein —R 8 and —R 9 are monovalent radicals comprising one or more carbons.

5. The composition of claim 1 , wherein each linking group is a thiocarbamate group.

6. A method, comprising:

applying a chemical and/or physical treatment to a porous support membrane to increase its hydrophilicity, thereby forming a treated porous support membrane;

disposing, on a surface of the treated porous support membrane, a mixture comprising i) a multi-functional isocyanate crosslinking agent comprising two or more isocyanate groups, ii) a solvent, iii) an optional accelerator, and iv) a crosslinkable poly(meth)acrylate, thereby forming an initial film layer disposed on the surface, wherein the crosslinkable poly(meth)acrylate comprises a) a first repeat unit comprising a first side chain ester comprising a poly(alkylene oxide) chain segment, b) a second repeat unit comprising a second side chain ester group comprising a nucleophilic group selected from the group consisting of alcohols, thiols, and combinations thereof, wherein the nucleophilic group is capable of reacting with the multi-functional isocyanate crosslinking agent, and c) a third repeat unit comprising a hydrophobic side chain group not capable of reacting with the multi-functional isocyanate crosslinking agent; and

treating the initial film layer thermally, photolytically, chemically, or by a combination thereof, thereby forming a composite filtration membrane comprising a selective layer disposed on the surface of the treated porous support membrane, the selective layer comprising a crosslinked poly(meth)acrylate, the crosslinked poly(meth)acrylate comprising a linking group produced by a reaction of the nucleophilic group with the multi-functional isocyanate crosslinking agent, the linking group selected from the group consisting of carbamates, ureas, thiocarbamates, and combinations thereof.

7. The method of claim 6 , wherein the isocyanate crosslinking agent has the formula (7):

R 7 NCO) m   (7),

wherein

m is an integer greater than or equal to 2, and

R 7 represents a core structure having a valency of m and comprising from 1 to 10,000 carbons.

8. The method of claim 6 , wherein the crosslinkable poly(meth)acrylate has the formula (5),

wherein

a′, b′, and c′ are positive numbers,

each —R 1 is independently a hydrogen or methyl group,

—R 2 — is a divalent radical selected from the group consisting of ethylene, 2-propylene, butylene, and combinations thereof,

n is a positive integer greater than 1, and

—Z 1 is a monovalent radical selected from the group consisting of —H, —R 3 , -L 1 -OH, -L 1 -NH 2 , -L 1 -N(H)R 3 , -L 1 -N(R 3 ) 2 , -L 1 -SH, and -L 1 -SR 3 , wherein —R 3 is a monovalent radical comprising 1 to 20 carbons,

-L 1 - is a divalent linking group comprising 1 to 20 carbons,

—R 4 — is a linear, branched or cyclic divalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups,

—X 1 is a nucleophilic monovalent radical selected from the group consisting of —OH and —SH, wherein —X 1 is capable of reacting with the multi-functional isocyanate crosslinking agent to form a covalent bond, and

—W 1 is a monovalent radical comprising two or more carbons.

9. The method of claim 8 , wherein —W′ is —CO 2 R 6 , wherein —R 6 is a linear, branched or cyclic monovalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups, and —R 6 is not capable of reaction with an isocyanate.

10. The method of claim 6 , wherein the first repeat unit of the crosslinkable poly(meth)acrylate is derived from a poly(ethylene glycol) methyl ether methacrylate (MPEGMA), the second repeat unit is derived from 2-hydroxyethyl methacrylate (HEMA), and the third repeat unit is derived from methyl methacrylate (MMA).

11. The method of claim 6 , wherein the multi-functional isocyanate crosslinking agent is selected from the group consisting of

and

combinations thereof, wherein —R 8 and —R 9 are monovalent radicals comprising one or more carbons.

12. The method of claim 6 , wherein the crosslinked poly(meth)acrylate has the formula (8):

wherein

n is a positive integer greater than 1,

m is a positive integer greater than or equal to 2,

a′, b′, and c′ are positive numbers,

j represents an average number of bridging groups bound to one poly(meth)acrylate chain, j being greater than or equal to 1,

k represents an average number of poly(meth)acrylate chains bound to one bridging group, k being greater than or equal to 1,

x′ is a positive number less than or equal to b′,

each —R 1 is independently a hydrogen or methyl group,

—R 2 — is a divalent radical selected from the group consisting of ethylene, 2-propylene, butylene, and combinations thereof,

—R 4 — is a linear, branched or cyclic divalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups,

—W 1 is a monovalent radical comprising two or more carbons,

R 7 is a bridging group having a valency of m and comprising 1 to 10,000 carbons,

—N(H)C(═O)-Q 1 - is a divalent linking group selected from the group consisting of carbamates, and thiocarbamates,

—Z 1 is a monovalent radical selected from the group consisting of —H, —R 3 , -L 1 -OH, -L 1 —NH 2 , -L 1 -N(H)R 3 , -L 1 -N(R 3 ) 2 , -L 1 -SH, and -L 1 -SR 3 , wherein —R 3 is a monovalent radical comprising 1 to 20 carbons,

-L 1 - is a divalent radical comprising 1 to 20 carbons,

-Q 1 - is a divalent radical selected from the group consisting of —O— and —S—, and

—X 1 is a nucleophilic monovalent radical selected from the group consisting of —OH and —SH.

13. The method of claim 12 , wherein —R 2 — is ethylene, —Z 1 is methyl, —X 1 is hydroxyl, -Q 1 - is —O—, x′=b′, and m is 3 or more.

14. The method of claim 12 , wherein W′ is —CO 2 R 6 , wherein —R 6 is a linear, branched or cyclic monovalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups.

15. A method, comprising:

disposing, on a temporary support, a mixture comprising i) a multi-functional isocyanate crosslinking agent comprising two or more isocyanate groups, ii) a solvent, iii) an optional accelerator, and iv) a crosslinkable poly(meth)acrylate, thereby forming an initial film layer, wherein the crosslinkable poly(meth)acrylate comprises a) a first repeat unit comprising a first side chain ester comprising a poly(alkylene oxide) chain segment, b) a second repeat unit comprising a second side chain ester group comprising a nucleophilic group selected from the group consisting of alcohols, thiols, and combinations thereof, wherein the nucleophilic group is capable of reacting with the multi-functional isocyanate crosslinking agent, and c) a third repeat unit comprising a hydrophobic side chain group not capable of reacting with the multi-functional isocyanate crosslinking agent;

treating the initial film layer thermally, photolytically, chemically, or by a combination of the foregoing techniques, thereby forming a layer of crosslinked poly(meth)acrylate comprising a linking group produced by reaction of the nucleophilic group with the multi-functional isocyanate crosslinking agent, the linking group selected from the group consisting of carbamates, thiocarbamates, and combinations thereof;

optionally removing solvent, if present, from the layer of crosslinked poly(meth)acrylate; and

separating the layer of crosslinked poly(meth)acrylate from the temporary support, thereby providing a self-supporting selective layer for fluid filtration.

16. The method of claim 15 , further comprising layering the self-supporting selective layer with a porous support membrane, thereby forming a composite filtration membrane.

17. A composite filtration membrane, comprising:

a porous support membrane; and

a selective layer comprising a crosslinked poly(meth)acrylate disposed on one or more faces of the porous support membrane, the crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones covalently linked to a bridging group, the backbones comprising i) respective first repeat units, each of which comprises a first side chain ester moiety comprising a hydrophilic poly(alkylene oxide) chain segment, ii) respective second repeat units, each of which comprises a second side chain ester moiety directly linked to the bridging group through a linking group selected from the group consisting of carbamate groups and thiocarbamate groups, and iii) respective third repeat units, each of which comprises a hydrophobic side chain moiety not directly linked to any bridging group.

18. The composite filtration membrane of claim 17 , wherein each linking group is a carbamate group.

19. The composite filtration membrane of claim 17 , wherein the bridging group is selected from the group consisting of

and

combinations thereof, wherein —R 8 and —R 9 are monovalent radicals comprising one or more carbons.

20. The composite filtration membrane of claim 17 , wherein the selective layer has a thickness between 20 nm and 10 micrometers.

21. The composite filtration membrane of claim 17 , wherein the composite filtration membrane is suitable for purifying a water mixture, and has improved anti-fouling and/or salt rejection properties compared to the porous support membrane.

22. A composition, comprising:

a crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones; wherein each of the two or more backbones is connected to i) a crosslinked ester side chain moiety, the crosslinked ester side chain moiety being covalently linked to a bridging group by a linking group selected from the group consisting of carbamate groups and thiocarbamate groups, ii) a hydrophilic side chain ester moiety comprising a poly(alkylene oxide) chain segment, and iii) a hydrophobic side chain moiety not directly linked to any bridging group.

23. The composition of claim 22 , wherein the composition has anti-fouling and/or salt rejection properties suitable for fluid purification.

24. The composition of claim 22 , wherein each linking group is a carbamate group.

25. The composition of claim 22 , wherein the bridging group is selected from the group consisting of

and

combinations thereof, wherein —R 8 and —R 9 are monovalent radicals comprising one or more carbons.

26. The composition of claim 22 , wherein each linking group is a thiocarbamate group.

27. A composition, comprising:

a crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones covalently linked to a bridging group, the backbones comprising i) respective first repeat units, each of which comprises a first side chain ester moiety comprising a hydrophilic poly(alkylene oxide) chain segment, ii) respective second repeat units, each of which comprises a second side chain ester moiety directly linked to the bridging group through a linking group selected from the group consisting of carbamate groups, urea groups, and thiocarbamate groups, and iii) respective third repeat units, each of which comprises a hydrophobic side chain moiety not directly linked to any bridging group, wherein the crosslinked poly(meth)acrylate has the formula (8):

wherein

n is a positive integer greater than 1,

m is a positive integer greater than or equal to 2,

a′, b′, and c′ are positive numbers,

j represents an average number of bridging groups bound to one poly(meth)acrylate chain, j being greater than or equal to 1,

k represents an average number of poly(meth)acrylate chains bound to one bridging group, k being greater than or equal to 1,

x′ is a positive number less than or equal to b′,

each —R 1 is independently a hydrogen or methyl group,

—R 2 — is a divalent radical selected from the group consisting of ethylene, 2-propylene, butylene, and combinations thereof,

—R 4 — is a linear, branched or cyclic divalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups,

—W 1 is a monovalent radical comprising two or more carbons,

R 7 is a bridging group having a valency of m and comprising 1 to 10,000 carbons,

—N(H)C(═O)-Q 1 - is a divalent linking group selected from the group consisting of carbamates, ureas, and thiocarbamates,

—Z 1 is a monovalent radical selected from the group consisting of —H, —R 3 , -L 1 -OH, -L 1 —NH 2 , -L 1 -N(H)R 3 , -L 1 -N(R 3 ) 2 , -L 1 -SH, and -L 1 -SR 3 , wherein —R 3 is a monovalent radical comprising 1 to 20 carbons,

-L 1 - is a divalent radical comprising 1 to 20 carbons,

-Q 1 - is a divalent radical selected from the group consisting of —O—, —N(H)—, —N(R 5 )—, and —S—, wherein —R 5 is a monovalent radical comprising 1 to 20 carbons, and

—X 1 is a nucleophilic monovalent radical selected from the group consisting of —OH, —NH 2 , —N(H)R 5 , and —SH.

28. The composition of claim 27 , wherein —R 2 — is ethylene, —Z 1 is methyl, —X 1 is hydroxyl, -Q 1 - is —O—, x′=b′, and m is 3 or more.

29. The composition of claim 27 , wherein W′ is —CO 2 R 6 , wherein —R 6 is a linear, branched or cyclic monovalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups.

30. A composition, comprising:

a crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones covalently linked to a bridging group, the backbones comprising i) respective first repeat units, each of which comprises a first side chain ester moiety comprising a hydrophilic poly(alkylene oxide) chain segment, ii) respective second repeat units, each of which comprises a second side chain ester moiety directly linked to the bridging group through a linking group selected from the group consisting of carbamate groups, urea groups, and thiocarbamate groups, and iii) respective third repeat units, each of which comprises a hydrophobic side chain moiety not directly linked to any bridging group, wherein the crosslinked poly(meth)acrylate has the formula (9):

wherein

n is a positive integer greater than 1,

a′, b′, and c′ are positive numbers,

m is a positive integer greater than or equal to 2,

j represents the average number of bridging groups bound to one poly(meth)acrylate chain, j being greater than or equal to 1,

k represents the average number of poly(meth)acrylate chains bound to one bridging group, k being greater than or equal to 1,

y′ is a positive number less than or equal to a′,

x′ is a positive number less than or equal to b′,

each —R 1 is independently a hydrogen or methyl group,

—R 2 — is a divalent radical selected from the group consisting of ethylene, 2-propylene, butylene, and combinations thereof,

—R 4 — is a linear, branched or cyclic divalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups,

R 7 is a bridging group having a valency of m and comprising 1 to 10,000 carbons,

—W 1 is a monovalent radical comprising two or more carbons,

—N(H)C(═O)-Q 1 - is a divalent linking group selected from the group consisting of carbamates, ureas, and thiocarbamates,

-Q 1 - is a divalent radical selected from the group consisting of —O—, —N(H)—, —N(R 5 )—, and —S—,

—N(H)C(═O)-Q 2 - is a divalent linking group selected from the group consisting of carbamates, ureas, and thiocarbamates,

-Q 2 - is a divalent radical selected from the group consisting of —O—, —NH—, —N(R 3 )—, —S—, -L 1 -O—*, -L 1 -NH—*, -L 1 -N(R 3 )—*, and -L 1 -S—* wherein the starred bond represents the point of attachment to a carbonyl of a linking group,

—Z 1 is a monovalent radical selected from the group consisting of —H, —R 3 , -L 1 -OH, -L 1 -NH 2 , -L 1 -N(H)R 3 , -L 1 -N(R 3 ) 2 , -L 1 -SH, and -L 1 -SR 3 ,

—R 3 is a monovalent radical comprising 1 to 20 carbons,

-L 1 - is a divalent radical comprising 1 to 20 carbons,

—X 1 is a monovalent nucleophilic monovalent radical selected from the group consisting of —OH, —NH 2 , —N(H)R 5 , and —SH, and

—R 5 is a monovalent radical comprising 1 to 20 carbons.

31. The composition of claim 30 , wherein —R 2 — is ethylene, —Z 1 is methyl, —X 1 is hydroxyl, -Q 1 - is —O—, x′=b′, and m is 3 or more.

32. The composition of claim 30 , wherein W′ is —CO 2 R 6 , wherein —R 6 is a linear, branched or cyclic monovalent radical selected from the group consisting of alkylenes, fluoroalkylenes, arylenes, arylalkylenes, alkylarylenes, and silicon containing groups.

33. A composition, comprising:

a crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones covalently linked to a bridging group, the backbones comprising i) respective first repeat units, each of which comprises a first side chain ester moiety comprising a hydrophilic poly(alkylene oxide) chain segment, ii) respective second repeat units, each of which comprises a second side chain ester moiety directly linked to the bridging group through a linking group selected from the group consisting of carbamate groups, urea groups, and thiocarbamate groups, and iii) respective third repeat units, each of which comprises a hydrophobic side chain moiety not directly linked to any bridging group;

wherein the bridging group is selected from the group consisting of

and

combinations thereof, wherein —R 8 and —R 9 are monovalent radicals comprising one or more carbons.

34. A composition, comprising:

a crosslinked poly(meth)acrylate comprising two or more poly(meth)acrylate backbones; wherein each of the two or more backbones is connected to i) a crosslinked ester side chain moiety, the crosslinked ester side chain moiety being covalently linked to a bridging group by a linking group selected from the group consisting of carbamate groups, urea groups, and thiocarbamate groups, ii) a hydrophilic side chain ester moiety comprising a poly(alkylene oxide) chain segment, and iii) a hydrophobic side chain moiety not directly linked to any bridging group;

wherein the bridging group is selected from the group consisting of

and

combinations thereof, wherein —R 8 and —R 9 are monovalent radicals comprising one or more carbons.