Analysis of water selfhyphen;diffusion in polycrystalline lamellar systems by pulsed field gradient nuclear magnetic resonance experiments

摘要

A study of the water selfhyphen;diffusion in polycrystalline lamellar systems, by pulsed field gradient spinhyphen;echo (PFGhyphen;SE) nuclear magnetic resonance (NMR) experiments, is reported here. Our analysis confirmed the validity of previous equations for bidimensional water selfhyphen;diffusion in lamellar lyomesophases and clarified their applicability limits. Depending on the diffusion experimental time range, two different procedures can be built up; for wide amplitude windows, the experimental diffusion coefficients are correlated to the fraction of bound water, whereas for short times it has been possible to point out the lsquo;lsquo;obstruction factorrsquo;rsquo; to diffusion. Experimental support for the theoretical findings was inferred by investigation of the lamellar mesophase of the binary system water/sodiumhyphen;bishyphen;2hyphen;ethylhexyl sulfosuccinate (AOT). It confirmed the existence of some defects in the lamellae at water concentration higher than 70 wt.thinsp;percnt;.