title: Temperature-induced vesicle to micelle transition in cationic/cationic mixed surfactant systems.
abstract: Temperature-induced vesicle to micelle transition (VMT), which has rarely been reported in cationic/cationic mixed surfactant systems, was systemically studied in a didodecyldimethylammonium bromide (DDAB)/dodecyltrimethylammonium chloride (DTAC) aqueous solution. We investigated the effect of temperature on DDAB/DTAC aqueous solutions by means of turbidity, conductivity, cryo-TEM, a UV-vis spectrophotometer, and a steady-state fluorescence spectrometer. It was found that increasing temperature could induce the transformation from the vesicle to the micelle in this cationic/cationic mixed surfactant system. The degree of transformation can be easily controlled by the operation temperature. Additionally, by adjusting the proportion of the mixed cationic/cationic systems and employing cationic surfactants with different chain-lengths, we were able to conclude that the hydrophobic tail length of the surfactant affects the aggregation behavior of cationic/cationic mixed surfactant systems as a function of temperature. It is universal to induce the transformation from the vesicle to the micelle by temperature in cationic/cationic mixed surfactant systems. A possible mechanism for the temperature-induced VMT was proposed based on the experimental results.
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. wli@cnu.edu.cn.
authors.forename: Yanjuan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. wli@cnu.edu.cn.
authors.forename: Lifei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. wli@cnu.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. wli@cnu.edu.cn.
authors.forename: Xiuniang
authors.initials: X
authors.lastname: Tan
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. wli@cnu.edu.cn.
authors.forename: Tian
authors.initials: T
authors.lastname: Luo
authors.affiliation: Department of Chemistry, Capital Normal University, Beijing 100048, China. wli@cnu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Li