Poly(ether sulfone) membranes with photo-responsive permeability

Novel polyethersulfone (PES) membranes with photo-responsive permeability based on the host–guest complex between azobenzene (Azo) and β-cyclodextrin (β-CD) were designed via direct blending with Azo and β-CD modified PES, and poly (ethylene glycol) (PEG) was used as the “bridge” between Azo/β-CD and PES. The behavior of the Azo sliding out of or inserting into β-CD under different external irradiations induced the photo-responsive permeability for the membranes, which was demonstrated by investigating the water fluxes through the membranes under the external irradiations at 450 and 365 nm. Simultaneously, the change of the pore sizes was confirmed to be responsible for the photo-responsibility of the prepared membranes, by investigating the water contact angle and standard PEG molecule permeation under the various external irradiations. The utilization of the supramolecular self-assembly was a new method for the design and preparation of stimuli-responsive membranes, which might be applicable in designing other sensitive membranes.