Showing papers by "Samo Kralj published in 1989"

Nuclear magnetic relaxation in small nematic droplets induced by molecular self‐diffusion

Abstract: Nuclear magnetic relaxation caused by self‐diffusion induced modulation of the intramolecular nuclear interactions in nematic liquid crystal droplets embedded in a solid polymer matrix is analyzed in order to show when it allows the determination of the structure of such confined systems. Both the frequency and temperature dependences of the relaxation rates T−11 and T−11ρ are calculated for radial and bipolar nematic droplet structures. Special attention is given to the effect of the boundary layer nematic phase. Translationally induced modulation is in most cases an effective relaxation mechanism only in the low frequency range (

Proton N.M.R. lineshape in nematic microdroplets

Abstract: The dependence of the proton N.M.R. absorption spectrum on nematic director configuration and molecular self-diffusion in nematic submicrondroplets is analysed. The lineshape is evaluated numerically for radial and bipolar director configuration. The motional averaging is taken into account by means of a numerical simulation of the molecular diffusion which induces slow molecular reorientations due to non-uniform orientational ordering in the droplet. This diffusion process strongly affects the absorption spectra of the radial configuration, whereas spectra of the bipolar configuration are only slightly influenced. The possibility of determinating the submicrometre nematic droplet structures using the proton N.M.R. lineshape is discussed.