Journal of Membrane Science, Vol.326, No.2, 618-626, 2009
Temperature-dependent molecular-recognizable membranes based on poly(N-isopropylacrylamide) and beta-cyclodextrin
A novel temperature-dependent molecular-recognizable membrane, poly(N-isopropylacylamide-co-glycidyl methacrylate/cyclodextrin)-grafted-polyethylene terephthalate (P(NIPAM-co-GMA/CD)-g-PET) membrane, is prepared by the combination of plasma-induced pore-filling grafting polymerization and chemical reaction. Scanning electron microscope (SEM) images show that the surfaces and cross-sections of the prepared membranes are uniformly grafted by polymeric layer. Fourier transform infrared (FT-IR) results show that CDs are successfully induced onto the P(NIPAM-co-GMA) grafted chains through reaction with epoxy groups. When the environmental temperature increases from 25 degrees C to 45 degrees C, the contact angle of prepared P(NIPAM-co-GMA/CD)-g-PET membrane increases from 65 degrees to 76.9 degrees; whereas, that of substrate membrane decreases from 84.8 degrees to 77.1 degrees. During the dynamic adsorption experiments, the guest 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS) molecules are adsorbed onto the P(NIPAM-co-GMA/CD)-g-PET membrane at lower temperature (25 degrees C) and desorbed from it at higher temperature (40 degrees C) with good repeatability. This phenomenon of adsorption at low temperature and desorption at high temperature of the P(NlPAM-co-GMA/CD)-g-PET membrane is attributable to both the "swollen-shrunken" configuration change of P(NIPAM-co-GMA) grafted chains and the molecular recognition of CD toward ANS. The P(NIPAM-co-GMA/CD)-g-PET membrane show both good thermo-responsibility and temperature-dependent molecular-recognizable characteristics toward guest molecules, which is highly potential to be applied in temperature-controlled affinity separations. (C) 2008 Elsevier B.V. All rights reserved.
Keywords:Track-etched membrane;Thermo-responsive polymer;Host-guest molecular recognition;Poly(N-isopropylacrylamide);Cyclodextrin