NMR molecular dynamics study of chromonic liquid crystals Edicol Sunset Yellow doped with salts

J. MARTINS; F. VACA CHAVEZ; PEDRO J. SEBASTIÃO

MAGNETIC RESONANCE IN CHEMISTRY

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2014

0749-1581

We investigate the effect of monoatomic salts on the molecular dynamics in the nematic and isotropic phases formed by the chromonic liquid crystal Edicol Sunset Yellow. The studywas carried out using proton nuclear magnetic resonance relaxometry. To analyse the effect of incorporation of additional sodium chloride or lithium chloride on the solutions? molecular dynamics, the spin-lattice relaxation time was measured for Larmor frequencies between 10 kHz and 100 MHz. In the nematic phase, the presence of additional sodium or lithium ions seems to contribute to an increase of the rotations/reorientations correlation times in comparison with the mixture without extra ions. The collective motions detected by protonNMRrelaxometry are associated with collective fluctuations of molecules within the stacks in the nematic phase and with order parameter fluctuations in the isotropic phase