Formation of Multilamellar Vesicles in the Systems of Decyltrimethylammonium hydroxides/2-hydroxy 1-carboxy-naphthoate and Octyltrimethylammonium hydroxides/2-hydroxy 1-carboxy-naphthoate

Abstract

Abstract We have investigated the phase behavior and characterized the microstructure of the phases that result from mixing of alkyltrimethylammonium hydroxides CxTAOH (x = 10.8) with 2-hydroxy 1-carboxy-naphthoate. We compare the results of this work with the published one of alkyltrimethylammonium 2-hydroxy-1-carboxy-naphthoate (CxTA 2,1 HCN, x = 16.14 or 12) [2]. With increasing counter-ion surfactant ratio r we observed transition from the isotropic L1-phase to multilamellar vesicles (MLV) Lα-phase. The single phases are separated by a two phase L1/Lα region. The phases were characterized with FF-TEM, rheological and SANS measurements. For 100 mM solution of either C8TAOH/2,1 HNC or C10TAOH/2,1 HNC, both MLV phases behave like a weak gel and have a yield stress value. It is thus shown that it is possible to prepare viscoelastic surfactant solutions with a small yield stress value from single chain surfactants with decyl or octylchain.