LAUSR

ABSTRACT The lyotropic lamellar mesophase consists of amphiphilic molecules arranged in bilayer sheets separated by layers of water . Among its various rheological properties, two are worth mentioning: yield-point and viscoelasticity. In this work, we studied lamellar samples of lauryl sulfate /Decanol /water system, as described in the phase diagram proposed by Quist and colleagues. (molar ratio fixed in ). We have investigated the changes in and viscoelasticity properties as a function of the molar ratio . The lamellar mesophases are characterized by using polarized light microscopy and conoscopy. All the rheological measurements were performed using rotational and oscillatory rheometry. The results show that the lamellar phase exhibits gel-like behavior. The increase of molar ratio weakens the microstructure of the lamellar network, affecting the elastic properties and the yield stress values.