IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
artículos
Título:
Proton NMR relaxation study of molecular dynamics of chromonic liquid crystal Edicol Sunset Yellow
Autor/es:
HUGO CACHITAS; PEDRO J. SEBASTIÃO; GABRIEL FEIO; FABIAN VACA CHAVEZ
Revista:
LIQUID CRYSTALS
Editorial:
TAYLOR & FRANCIS LTD
Referencias:
Lugar: Londres; Año: 2014 p. 1080 - 1089
ISSN:
0267-8292
Resumen:
Proton nuclear magnetic resonance (1H NMR) relaxometry, over about five decades in Larmor frequency, and
pulsed field gradient NMR were used to study the molecular dynamics in the chromonic nematic and isotropic
phases of stacked molecules of the binary mixture composed by Edicol Sunset Yellow (ESY) and deuterated
water. Our results evidence that in both phases collective motions are responsible for the spin-lattice relaxation
dispersion in the Larmor frequency range below 1 MHz. In the nematic phase, the collective motion are attributed
to columnar undulations within the stacked molecules, while, in the isotropic phase, the results are explained by
local order fluctuations due to the formation of the stacks. The high frequency dispersion was explained by
individual molecular motions like rotations around and perpendicular to the stack axis, and also self-diffusion.