title: Conformational Changes of a Surface-Tethered Polymer during Radical Growth Probed with Second-Harmonic Generation.
abstract: The surface-induced polymerization of a chromophore-functionalized monomer was probed in situ for the first time using a nonlinear optical technique, second-harmonic generation. During the first hours of the polymerization reaction, dramatic changes in the tilt angle of the chromophore-functionalized side groups were observed. Following evaluation of the nonlinear optical data with those obtained from atomic force microscopy and ultraviolet-visible, we conclude that second-harmonic generation efficiently probes the polymerization reaction and the conformational changes of the surface-grafted polymer. With polymerization time, the conformation of the surface-tethered polymer changes from a conformation with the polymer backbone and its side groups flat on the surface, i.e., a "pancake" conformation, to a conformation where the polymer backbone is stretched away combined with tilted side groups or an enlarged tilt angle distribution, i.e., a "brush-type" conformation.
authors.affiliation: Department of Chemistry, University of Leuven , 3001 Leuven, Belgium.
authors.forename: Steven
authors.identifier: 0000-0003-3389-0348
authors.initials: S
authors.lastname: Deckers
authors.affiliation: Department of Chemistry, University of Leuven , 3001 Leuven, Belgium.
authors.forename: Maarten
authors.initials: M
authors.lastname: Bloemen
authors.affiliation: Department of Chemistry, University of Leuven , 3001 Leuven, Belgium.
authors.forename: Guy
authors.identifier: 0000-0003-1412-8454
authors.initials: G
authors.lastname: Koeckelberghs
authors.affiliation: Laboratorium voor Akoestiek en Thermische Fysica, Departement Natuurkunde en Sterrenkunde, Katholieke Universiteit (KU) Leuven , Celestijnenlaan 200D, 3001 Heverlee, Belgium.
authors.forename: Christ
authors.initials: C
authors.lastname: Glorieux
authors.affiliation: Department of Chemistry, University of Leuven , 3001 Leuven, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Verbiest
authors.affiliation: Catalysis Engineering, Applied Sciences, Delft University of Technology , 2629 Delft, Netherlands.
authors.forename: Monique A
authors.initials: MA
authors.lastname: van der Veen