Biological systems are the ultimate model for an effective selective permeation device. Biomimetic artificial channels based on the assembly of peptides have been previously integrated in vesicles and lipid layers with the expectation of leading in the future to a more efficient water purification and biological separation. We demonstrate here the design of scalable membranes constituted by synthesized copolymers with α-helical polypeptide blocks. They have unique featherlike and lamellar structures and were obtained from poly(styrene-b-γ-benzyl-l-glutamate) copolymers via phase inversion or spin-coating. The membranes were then hydrolyzed using acid vapor annealing, which preserved the helical morphology after hydrolysis. Water permeation up to 3.5 L m–2 h–1 bar–1 was obtained. Dialysis experiments with membranes prepared via phase inversion had high retention of cytochrome c. High rejection of cytochrome c and the negatively charged dye Brilliant Blue was demonstrated for the spin-coated membranes. The bioinspired membranes are developed for effective molecular separation, aiming at applications in the biotech industry.