Postfunctionalization of Nanoporous Block Copolymer Membranes via Click Reaction on Polydopamine for Liquid Phase Separation

In this work, an azido-modified dopamine derivative was synthesized and subsequently used to postfunctionalize the surface of nanoporous poly­(styrene)-block-poly­(4-vinylpyridine) diblock copolymer membranes. On the basis of this layer a continuative modification was realized by performing a “Click” reaction, namely, the Cu­(I)-catalyzed 1,3-dipolar cycloaddition, with different alkynes. While the Click reaction was monitored by X-ray photoelectron spectroscopy, the morphology of the membranes in the different states of modification was examined with scanning electron microscopy and atomic force microscopy. The membrane properties were characterized by measurements of contact angle and clean water permeance, retention tests, and protein adsorption. Independent from the alkyne applied during the Click reaction, the clean water permeance is approximately 1200 L m^–2 bar^–1 h^–1 and therefore slightly below the permeance of the pristine membrane. While the sharp molecular weight cutoff of the pristine membrane and all modified membranes is similar, antifouling properties as studied on the interaction of two model proteins (bovine serum albumin, hemoglobin) with the membranes turned out to be best for the membranes modified with 1-nonyne.