CiteULike: dchen's Spiess http://www.citeulike.org/user/dchen/author/Spiess CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2767626 <i>Physical Review Letters, Vol. 100, No. 10. (2008)</i><br /><br />The molecular dynamics of three dipole functionalized hexa-peri-hexabenzocoronenes have been studied using site-specific NMR techniques and dielectric spectroscopy as a function of temperature and pressure. These probes (i) suggest that the thermodynamic state completely controls the dynamic response, (ii) clarify the origin of two dynamic processes associated with the presence of two glass temperatures, and (iii) provide the first phase diagram for substances of this kind. Origin of the Complex Molecular Dynamics in Functionalized Discotic Liquid Crystals MM Elmahdy G Floudas M Mondeshki HW Spiess X Dou K Müllen doi:10.1103/PhysRevLett.100.107801 Physical Review Letters, Vol. 100, No. 10. (2008) 2008-05-07T22:55:49-00:00 Physical Review Letters 100 10 APS 2008 glass liquidcrystal phase http://www.citeulike.org/user/dchen/article/1304855 <i>Physical Review Letters, Vol. 81, No. 13. (1998), 2727.</i><br /><br />We directly measure the equilibrium length scale of dynamic heterogeneities close to the glass transition by means of a new multidimensional NMR experiment. The spatial information is gained from a proton spin diffusion experiment combined with two 2D 13 C exchange sequences via appropriate back and forth transfer of magnetization between 13 C and 1 H spins. For poly(vinyl acetate) at 10 K above the glass transition we detected a length scale of 3±1 nm. Length Scale of Dynamic Heterogeneities at the Glass Transition Determined by Multidimensional Nuclear Magnetic Resonance U Tracht M Wilhelm A Heuer H Feng K Schmidt-Rohr HW Spiess doi:10.1103/PhysRevLett.81.2727 Physical Review Letters, Vol. 81, No. 13. (1998), 2727. 2007-05-18T06:44:44-00:00 Physical Review Letters 81 13 2727 American Physical Society experiment heterogeneity mnmr