title: Probing carbonyl-water hydrogen-bond interactions in thin polyoxazoline brushes.
abstract: Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule-solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situ infrared ellipsometry. Focus was put on interactions of the brushes' carbonyl groups with water molecules. Different polymer-water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20-45 °C was identified by frequency shifts and intensity changes of the amide I band.
authors.affiliation: Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Department Berlin, Schwarzschildstraße 8, 12489 Berlin, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Kroning
authors.affiliation: Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Department Berlin, Schwarzschildstraße 8, 12489 Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Furchner
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Str. 6, 01069 Dresden, Germany and Faculty of Science, Department of Chemistry, Chair of Physical Chemistry of Polymeric Materials, Technische Universität Dresden, Bergstr. 66, 01069 Dresden, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Adam
authors.affiliation: Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Str. 6, 01069 Dresden, Germany and Department of Chemistry, University of Nebraska-Lincoln, Hamilton Hall, 639 North 12th Street, Lincoln, Nebraska 68588.
authors.forename: Petra
authors.initials: P
authors.lastname: Uhlmann
authors.affiliation: Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Department Berlin, Schwarzschildstraße 8, 12489 Berlin, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Hinrichs
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions / Q000528:radiation effects*; D010080:Oxazoles / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D010080:Oxazoles; C577913:poly(2-oxazoline); D014867:Water