title: Molecular motions in supercooled and glassy ibuprofen: deuteron magnetic resonance and high-resolution rheology study.
abstract: Using deuteron nuclear magnetic resonance, the molecular motions of specifically isotope-labeled ibuprofen were probed at the carboxylic group and at the methin group next to it. Spin relaxometry revealed slight differences between the molecular motions of the two isotopomers that are rationalized with reference to the hydrogen bonding of the COOH moiety. In the glassy state, a small-angle jump process among about four sites, related to the so-called γ-process, was identified using stimulated-echo spectroscopy. Indications for a Debye-like process, previously found to leave a weak signature in the dielectric loss, could not unambiguously be detected in magnetic resonance or shear mechanical experiments carried out for supercooled liquid ibuprofen.
authors.affiliation: †Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bauer
authors.affiliation: †Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Storek
authors.affiliation: †Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Gainaru
authors.affiliation: ‡Max Planck-Institut für Medizinische Forschung, 69120 Heidelberg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Zimmermann
authors.affiliation: †Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Böhmer
mesh_terms: D003903:Deuterium; D005898:Glass / Q000737:chemistry; D006860:Hydrogen Bonding; D007052:Ibuprofen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009038:Motion; D012212:Rheology; D013696:Temperature
chemical_list: D003903:Deuterium; D007052:Ibuprofen