Zwitterion-functionalized multicomponent copolymers and associated polymer blends and membranes

A membrane comprising:

• a multicomponent copolymer comprising at least one repeat unit AC having a structure (I), at least one repeat unit DC comprising a structural unit having a structure (II), and at least one repeat unit BC comprising a structural unit having a structure (III):
• wherein “a”, “b” and “c” are independently at each occurrence 1, 2, 3, or 4;
• “k” ranges from 0 to 10;
• “o”, “p”, “m” and “n” are each, independently, 0 or 1;
• R1, R2 and R5 are independently at each occurrence a hydrogen atom, a halogen atom, a nitro group, a C3-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;
• R3 and Y are each, independently, a hydrogen atom, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical;
• R4 is a bond, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical, and
• wherein the copolymer has a formula [(AC)P*S-(DC)Z*S-(BC)R] wherein S is a mole fraction of a total piperazine content, P*S is a mole fraction of a piperazine content of the repeat units AC, Z*S is a mole fraction of a zwitterion content of the repeat units DC, and R is a mole fraction of the repeat units BC in the copolymer, and wherein P+Z=1, S+R=1 wherein P*S ranges from about 0.01 to about 0.4 and Z*S ranges from about 0.10 to about 0.6.