Membranes comprising functional polyarylether having structural units of formula II are useful for hemodialysis and hemofiltration: wherein X is selected from Br, NR4R5, OOCR6, OR7, NR4COR5, NR4CONR5R6, NR4COOR5R6 and combinations thereof; R1, R2 and R3 are independently at each occurrence H, X, halo, cyano, nitro, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, a C3-C12 aromatic radical or a combination thereof; R4 and R5 are independently H, a C1-10 aliphatic radical, a C3-C12cycloaliphatic radical, a C3-C12 aromatic radical, or a combination thereof; R6 is H, a C2-10 aliphatic radical, a C3-C12 cycloaliphatic radical, a C3-C12 aromatic radical or a combination thereof; R7 is OCH2CH2(OCH2CH2)nOH or OOCCH2(OCH2CH2)nCH3; Q is a direct bond, O, S, CH2, alkenyl, alkynyl, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, a C3-C12 aromatic radical or a combination thereof; Z is a direct bond, O, S, CH2, SO, SO2, CO, phenylphospinyl oxide, alkenyl, alkynyl, a C1-C12aliphatic radical, a C3-C12cycloaliphatic radical, a C3-C12 aromatic radical or a combination thereof; a, b, and c are independently 1 or 2; and m, n and p are independently 0 or 1.