“…Cationic surfactants, decyltrimethylammonium bromide DeTAB 9 , dodecyltrimethyl ammonium bromide DTAB 6 , and tetradecyltrimethylammonium bromide TTAB 10 purchased from Wako Pure Chemical Industries, Ltd., and anionic surfactants, lithium dodecyl sulfate LiDS, Sigma-Aldrich Co. 11 and lithium perfl uorooctane sulfonate LiFOS, Wako Pure Chemical Industries, Ltd. 11 were purified appropriately by recrystallization from the mixture of organic solvents. The purity of surfactants was checked by observing no minimum on the surface tension versus molarity of aqueous solution of surfactants curves around the cmc.…”