Zwitterion-functionalized block copolymer membranes and associated block copolymer composition

1. A membrane, comprising:

a block copolymer comprising at least one block A comprising structural units having a formula (I), and at least one block B comprising structural units having a formula (II):

wherein “a” and “b” are independently at each occurrence 0, 1, 2, 3, or 4;

“n”, “p”, “q” and “r” are independently 0 or 1;

R1 and R2 are independently at each occurrence a hydrogen atom, a nitro group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

R3 is a hydrogen atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

R4 is a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

Y is independently at each occurrence a bond, an oxygen atom, a sulfur atom, a sulfinyl group, a sulfonyl group, a phenylphosphine group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

Q is a bond, an oxygen atom, a sulfur atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; and

Z is a zwitterion functional group.

2. The membrane of claim 1 , wherein the block B comprises structural units having a formula (III):

wherein “a” and “b” are independently at each occurrence 0, 1, 2, 3, or 4;

“n”, “p”, “q” and “r” are independently 0 or 1;

Q is a bond, an oxygen atom, a sulfur atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; and

R1 and R2 are independently at each occurrence a hydrogen atom, a nitro group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical.

3. The membrane of claim 1 , wherein the zwitterion functional group comprises sulfobetaine, carboxybetaine, phosphorylcholine, or combinations thereof.

4. The membrane of claim 1 , wherein the block A comprises structural units having a formula (IV):

wherein R 3 and R 5 are independently at each occurrence a hydrogen atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical; and

R 4 and R 6 are independently a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical.

5. The membrane of claim 1 , wherein the block A further comprises structural units having a formula (V):

R 3 and R 5 are independently at each occurrence a hydrogen atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical; and

R 4 is a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical.

6. The membrane of claim 1 , wherein a mole fraction of the zwitterion functional group in the block A is in a range from about about 5 percent to about 100 percent.

7. The membrane of claim 1 , wherein a mole fraction of the zwitterion functional group in the block A is in a range from about about 35 percent to about 70 percent.

8. The membrane of claim 1 , wherein the number of repeat units in the block B is in a range from about 20 to about 200.

9. The membrane of claim 1 , wherein the number of repeat units in the block A is in a range from about 1 to about 25.

10. The membrane of claim 1 , wherein the block copolymer comprises structural units having a formula (VI):

wherein “a” and “b” are independently at each occurrence 0, 1, 2, 3, or 4;

“n”, “p”, “q” and “r” are independently 0 or 1;

“x” is an integer in a range from about 20 to about 200;

“y” is an integer in a range from about 1 to about 25;

Y is independently at each occurrence a bond, an oxygen atom, a sulfur atom, a sulfinyl group, a sulfonyl group, a phenylphosphine group, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical;

Q is a bond, an oxygen atom, a sulfur atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical;

W is independently at each occurrence a radical having a formula (VII) or (VIII):

with the proviso that at least one of W in the block copolymer is a radical having the formula (VIII);

R 1 and R 2 are independently at each occurrence a hydrogen atom, a nitro group, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical;

R 3 , R 5 , and R 7 are independently at each occurrence a hydrogen atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical; and

R 4 and R 6 are independently a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical.

11. The membrane of claim 1 , wherein the block copolymer comprises structural units having a formula (IX):

wherein “a” and “b” are independently at each occurrence 0, 1, 2, 3, or 4;

“n”, “p”, “q” and “r” are independently 0 or 1;

“x” is an integer in a range from about 20 to about 200;

“y” is an integer in a range from about 1 to about 25;

Y is independently at each occurrence a bond, an oxygen atom, a sulfur atom, a sulfinyl group, a sulfonyl group, a phenylphosphine group, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical;

Q is a bond, an oxygen atom, a sulfur atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical;

W is independently at each occurrence a radical having a formula (VII) or (VIII):

with the proviso that at least one W in the block copolymer is a radical having the formula (VIII);

R 1 and R 2 are independently at each occurrence a hydrogen atom, a nitro group, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical;

R 3 , R 5 , and R 7 are independently at each occurrence a hydrogen atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical; and

R 4 and R 6 are independently a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical.

12. The membrane of claim 1 , wherein the membrane has a hollow-fiber configuration.

13. A hollow-fiber module comprising a plurality of membranes as defined in claim 11 .

14. A hollow-fiber membrane for bio-separation, comprising a block copolymer comprising at least one block A comprising structural units having a formula (I), and at least one block B comprising structural units having a formula (II):

wherein “a” and “b” are independently at each occurrence 0, 1, 2, 3, or 4;

“n”, “p”, “q” and “r” are independently 0 or 1;

R1 and R2 are independently at each occurrence a hydrogen atom, a nitro group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

R3 is a hydrogen atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

R4 is a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

Y is independently at each occurrence a bond, an oxygen atom, a sulfur atom, a sulfinyl group, a sulfonyl group, a phenylphosphine group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;

Q is a bond, an oxygen atom, a sulfur atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical; and

Z is a zwitterion functional group.

15. The hollow-fiber membrane of claim 14 , wherein the block B comprises structural units having a formula (III)

wherein “a” and “b” are independently at each occurrence 0, 1, 2, 3, or 4;

“n”, “p”, “q” and “r” are independently 0 or 1;

Q is a bond, an oxygen atom, a sulfur atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; and

R1 and R2 are independently at each occurrence a hydrogen atom, a nitro group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical.

16. The hollow-fiber membrane of claim 14 , wherein the zwitterion functional group comprises sulfobetaine, carboxybetaine, phosphorylcholine, or combinations thereof.

17. The hollow-fiber membrane of claim 14 , wherein the block A comprises structural units having a formula (IV):

wherein R 3 and R 5 are independently at each occurrence a hydrogen atom, a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical; and

R 4 and R 6 are independently a C 1 -C 12 aliphatic radical, a C 3 -C 12 cycloaliphatic radical, or a C 3 -C 12 aromatic radical.

18. The hollow-fiber membrane of claim 14 , wherein the block A further comprises structural units having a formula (V):

R3 and R5 are independently at each occurrence a hydrogen atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; and

R4 is a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical.