Double Stimuli‐Responsive Isoporous Membranes via Post‐Modification of pH‐Sensitive Self‐Assembled Diblock Copolymer Membranes

Double stimuli‐responsive membranes are prepared by modification of pH‐sensitive integral asymmetric polystyrene‐ b ‐poly(4‐vinylpyridine) (PS‐ b ‐P4VP) diblock copolymer membranes with temperature‐responsive poly( N ‐isopropylacrylamide) (pNIPAM) by a surface linking reaction. PS‐ b ‐P4VP membranes are first functionalized with a mild mussel‐inspired polydopamine coating and then reacted via Michael addition with an amine‐terminated pNIPAM‐NH 2 under slightly basic conditions. The membranes are thoroughly characterized by nuclear magnetic resonance ( 1 H‐NMR), Fourier transform infrared spectroscopy and X‐ray‐induced photoelectron spectroscopy. Additionally dynamic contact angle measurements are performed comparing the sinking rate of water droplets at different temperatures. The pH‐ and thermo‐double sensitivities of the modified membranes are proven by determining the water flux under different temperature and pH conditions.