title: Reversible Calcium(II)-Ion Binding through an Apparent pKa Shift of Thermosensitive Block-Copolymer Micelles.
abstract: There is an increasing need for smart materials capable of removing multivalent ions from aqueous streams without the inconvenience of brine regeneration as in ion-exchange processes. Herein, we present a thermoresponsive micellar system consisting of polystyrene-poly(methoxy diethyleneglycol acrylate) block copolymer surfactants modified with carboxylic acid end groups (PS-PMDEGA-COOH) that can be used to switch between the adsorption and desorption of divalent calcium(II) cations by a mild temperature trigger, thus providing a new type of thermoregenerable ion-adsorbing materials. The switch of calcium(II)-binding capacity is demonstrated to result from a shift in the pKa value of the carboxylic acid groups by the collapse and redissolution of the PMDEGA block and the associated change in local polarity.
authors.affiliation: Process Development Group, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (The Netherlands).
authors.forename: Johannes P A
authors.initials: JP
authors.lastname: Custers
authors.affiliation: Process Development Group, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (The Netherlands).
authors.forename: Sjoerd F G M
authors.initials: SF
authors.lastname: van Nispen
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich-Schiller-University Jena, Humboldtstrasse 10, 07743 Jena (Germany).|Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Philosophenweg 7, 07743 Jena (Germany).
authors.forename: Aydin
authors.initials: A
authors.lastname: Can
authors.affiliation: Supramolecular Chemistry Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Ghent (Belgium) http://www.sc.ugent.be.
authors.forename: Victor R
authors.initials: VR
authors.lastname: de La Rosa
authors.affiliation: Supramolecular Chemistry Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Ghent (Belgium) http://www.sc.ugent.be.
authors.forename: Samarendra
authors.initials: S
authors.lastname: Maji
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich-Schiller-University Jena, Humboldtstrasse 10, 07743 Jena (Germany).|Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Philosophenweg 7, 07743 Jena (Germany).
authors.forename: Ulrich S
authors.initials: US
authors.lastname: Schubert
authors.affiliation: Process Development Group, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (The Netherlands).
authors.forename: Jos T F
authors.initials: JT
authors.lastname: Keurentjes
authors.affiliation: Supramolecular Chemistry Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Ghent (Belgium) http://www.sc.ugent.be. Richard.Hoogenboom@ugent.be.
authors.forename: Richard
authors.initials: R
authors.lastname: Hoogenboom
keywords: calcium(II) binding; responsive polymers; self-assembly; smart materials; thermoreponsive polymers