SWELLING OF A LYOTROPIC HEXAGONAL PHASE BY MONITORING THE RADIUS OF THE CYLINDERS

We report the elaboration of a lyotropic hexagonal mesophase with a ve ry large lattice parameter. The quaternary system studied displays a h exagonal phase of direct type, namely, nonpolar tubes in a polar mediu m: by varying the ionic force of the polar medium, i.e., by addition o f salt, we show that it is possible to realize hexagonal mesophases wi th swollen cylinders of monitored radius up to 17 nm. Moreover, from m icroscopic observations we have access to the elastic characteristics of the swollen lyotropic hexagonal phases, quantified by a penetration length lambda. We find that lambda increases with the swelling ratio and interpret this result via microscopic models.