Multiresponsive polymer conetworks capable of responding to changes in pH, temperature, and magnetic field: Synthesis, characterization, and evaluation of their ability for controlled uptake and release of solutes

Abstract

This study deals with the preparation of novel multiresponsive (magnetoresponsive, thermoresponsive and pH-responsive) nanocomposite conetworks consisting of oleic acid-coated magnetite nanoparticles (OA•Fe 3O 4), hydrophilic/thermoresponsive hexa(ethylene glycol) methyl ether methacrylate (HEGMA), hydrophobic/metal binding 2-(acetoacetoxy)ethyl methacrylate (AEMA), and pH-responsive/thermoresponsive N-diethylaminoethyl methacrylate (DEAEMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) moieties. Conventional free radical copolymerization was employed for the synthesis of random conetworks in the absence and presence of preformed OA•Fe 3O 4. Further, in characterization of these materials in regards to their swelling behavior in organic and aqueous solvents, thermal/thermoresponsive properties, and composition, assessment of their magnetic characteristics disclosed tunable superparamagnetic behavior. These systems were also evaluated toward their ability to adsorb and release a solute (benzoic acid) in a controlled manner upon varying the pH. © 2012 American Chemical Society.