title: 2D 129Xe EXSY of xenon atoms in a thermotropic liquid crystal confined to a controlled-pore glass.
abstract: Two-dimensional (129)Xe exchange spectroscopy (EXSY) NMR measurements are presented for xenon atoms dissolved in a thermotropic nematic Liquid Crystal (LC), Merck Phase 4, confined to a mesoporous Controlled-Pore Glass (CPG) material with an average pore diameter of 81 A. Experiments were carried out as a function of mixing time at two different temperatures in which Phase 4 appears in nematic and isotropic phases. The exchange rate constants of xenon atoms between two different sites were determined utilizing the intensities of diagonal and off-diagonal signals measured in the EXSY spectra. In the studied system, the sites are: (a) xenon dissolved in the bulk LC between the CPG particles; and (b) xenon in the LC confined inside the pores. The diffusion rate of xenon atoms between the various sites was observed to be very slow.
authors.affiliation: Department of Physical Sciences, NMR Research Group, University of Oulu, P.O. Box 3000, FIN-90014, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Tallavaara
authors.forename: Jukka
authors.initials: J
authors.lastname: Jokisaari
mesh_terms: D004058:Diffusion; D005898:Glass / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D016062:Porosity; D013499:Surface Properties; D013696:Temperature; D014978:Xenon / Q000737:chemistry*; D014979:Xenon Isotopes / Q000737:chemistry*
chemical_list: D014979:Xenon Isotopes; D014978:Xenon