title: Double stimuli-responsive ultrafiltration membranes from polystyrene-block-poly(N,N-dimethylaminoethyl methacrylate) diblock copolymers.
abstract: We report on the formation of self-supporting, double stimuli-responsive ultrafiltration membranes via the non-solvent-induced phase separation (NIPS) process. The polymers, polystyrene-block-poly(N,N-dimethylaminoethyl methacrylate) (PS-b-PDMAEMA), were synthesized via living anionic polymerization in THF using sec-butyllithium as initiator. Two amphiphilic diblock copolymers were used, S(81)D(19)(75) and S(68)D(32)(100). The membranes were cast from mixtures of THF and DMF. The influence of the solvent composition, the "open-time" before immersion into the coagulation bath, and the casting film thickness onto the membrane morphology were thoroughly investigated, and flux values obtained for the different membrane systems were compared. The higher content in hydrophilic polymer for S(68)D(32)(100) resulted in a better compatibility with the nonsolvent bath consisting of water, leading to a slower precipitation and thus an improved control of the phase separation occurring. Under certain conditions, ordered microphase-separated porous morphologies were observed in parts of the membrane cross-section. Further, the "smart" properties of those novel materials are shown for two representative systems. It could be demonstrated that both stimuli for PDMAEMA, pH and temperature, can be reversibly and independently applied in order to significantly change the transmembrane water flux.
authors.affiliation: Makromolekulare Chemie II and Makromolekulare Chemie I, Universitat Bayreuth, Universitasstrasse 30, D-95440 Bayreuth, and Technische Chemie II, Universitat Duisburg-Essen, Universitatsstrasse 2, D-45117 Essen.
authors.forename: Felix
authors.initials: F
authors.lastname: Schacher
authors.forename: Tobias
authors.initials: T
authors.lastname: Rudolph
authors.forename: Florian
authors.initials: F
authors.lastname: Wieberger
authors.forename: Mathias
authors.initials: M
authors.lastname: Ulbricht
authors.forename: Axel H E
authors.initials: AH
authors.lastname: Müller
mesh_terms: D002845:Chromatography / Q000379:methods; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008567:Membranes, Artificial; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D009757:Nylons / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D012542:Scattering, Radiation; D012997:Solvents / Q000737:chemistry; D014462:Ultrafiltration; D014867:Water / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D008689:Methacrylates; D009757:Nylons; D011108:Polymers; D012997:Solvents; C407037:poly(2-(dimethylamino)ethyl methacrylate); D014867:Water