@article {438, title = {Xe-129 Nmr-Studies of Hyper-Cross-Linked Polyarylcarbinols - Rigid Versus Flexible Structures}, journal = {Chemistry of Materials}, volume = {7}, year = {1995}, note = {Chem MaterRk993Times Cited:27Cited References Count:30}, month = {Jul}, pages = {1325-1332}, abstract = {

Xenon NMR is used with adsorption measurements to infer information about the microstructure of some novel hyper-cross-linked polyarylcarbinols. It is shown that rigidrod connecting units are necessary for microporosity in these systems, as hyper-cross-linked polymers based on flexible structures are found to have conventional surface areas and xenon NMR spectra. A microporous polymer based on rigid triarylcarbinol monomers shows high xenon uptake and a linear chemical shift variation with pressure at room temperature. Spin-lattice relaxation and cross-polarization dynamics are studied at low temperatures. In this regime the xenon has extremely long equilibration times, and the adsorption dynamics are complicated but give important insight into the polymer topology. The data are compared with two possible models of the polymer microstructwre.

}, keywords = {adsorption}, isbn = {0897-4756}, doi = {Doi 10.1021/Cm00055a008}, url = {://WOS:A1995RK99300008}, author = {Urban, C. and Mccord, E. F. and Webster, O. W. and Abrams, L. and Long, H. W. and Gaede, H. and Tang, P. and Pines, A.} } @article {475, title = {High-Field Cross-Polarization Nmr from Laser-Polarized Xenon to a Polymer Surface}, journal = {Journal of the American Chemical Society}, volume = {115}, year = {1993}, note = {J Am Chem SocLx752Times Cited:77Cited References Count:16}, month = {Sep 8}, pages = {8491-8492}, keywords = {gas}, isbn = {0002-7863}, doi = {Doi 10.1021/Ja00071a086}, url = {://WOS:A1993LX75200086}, author = {Long, H. W. and Gaede, H. C. and Shore, J. and Reven, L. and Bowers, C. R. and Kritzenberger, J. and Pietrass, T. and Pines, A. and Tang, P. and Reimer, J. A.} } @article {474, title = {Spin-Polarized Xe-129 Nmr-Study of a Polymer Surface}, journal = {Journal of Physical Chemistry}, volume = {97}, year = {1993}, note = {J Phys Chem-UsKp603Times Cited:51Cited References Count:48}, month = {Feb 25}, pages = {1649-1655}, abstract = {

A method for NMR studies of low surface area materials using optically pumped xenon gas is described. The method has been used to investigate spin-polarized xenon adsorbed onto poly(acrylic acid). The temperature dependence of the xenon-surface interaction, as measured by the xenon chemical shifts extrapolated to zero pressure, is shown to be consistent with a simple model of chemical exchange between the gas and adsorbed phases. The magnitude of the surface contribution to the Xe-129 chemical shift indicates a relatively strong interaction between xenon and poly(acrylic acid), possibly due to the polar carboxylic acid functional groups at the polymer surface. From the pressure dependence of the Xe-129 shift, the diffusion coefficient of xenon on poly(acrylic acid) is estimated to be 3.3 x 10(-5) cm2/s.

}, keywords = {temperature}, isbn = {0022-3654}, doi = {Doi 10.1021/J100110a029}, url = {://WOS:A1993KP60300029}, author = {Raftery, D. and Reven, L. and Long, H. and Pines, A. and Tang, P. and Reimer, J. A.} } @article {489, title = {Nmr of Optically Pumped Xenon Thin-Films}, journal = {Chemical Physics Letters}, volume = {191}, year = {1992}, note = {Chem Phys LettHp501Times Cited:25Cited References Count:25}, month = {Apr 10}, pages = {385-390}, abstract = {

NMR of Xe-129 has been observed in thin films of xenon frozen onto the surfaces of glass sample cells with various geometries. The Xe-129 polarization was enhanced by optical pumping, and the xenon was then transferred to a high-field pulsed NMR spectrometer allowing the observation of strong signals from xenon films of approximately 1-mu-m thickness. The line shape depends on the film geometry because of the bulk diamagnetic susceptibility chi(D) of solid xenon. The spectral line shape and resonance frequency also depend on temperature.

}, isbn = {0009-2614}, doi = {Doi 10.1016/0009-2614(92)85396-R}, url = {://WOS:A1992HP50100002}, author = {Raftery, D. and Long, H. and Reven, L. and Tang, P. and Pines, A.} }