pH-Regulated Molecular Self-Assemblies in a Cationic−Anionic Surfactant System: From a “1−2” Surfactant Pair to a “1−1” Surfactant Pair

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• 作者：Yiyang Lin ; Xue Han ; Xinhao Cheng ; Jianbin Huang ; Dehai Liang ; Cailan Yu
• 刊名：Langmuir
• 出版年：2008
• 出版时间：December 16, 2008
• 年：2008
• 卷：24
• 期：24
• 页码：13918-13924
• 全文大小：408K
• 年卷期：v.24,no.24(December 16, 2008)
• ISSN：1520-5827

文摘

With the aid of pH variation, direct transformation of a “1−1” cationic−anionic surfactant pair to a “1−2” cationic−anionic surfactant pair was attained in the system of cetyltrimethylammonium bromide and n-decylphosphoric acid. Owing to the transformation of a “1−1” pair to a “1−2” pair, diverse microstructures and peculiar phase behavior in this cationic−anionic surfactant mixture was obtained at different pH. It is proposed that pH can be manipulated for effectively tailoring the self-assembled organization in this cationic−anionic surfactant system, including spherical micelle, wormlike micelle, vesicle, and lamellar structure. In contrast to the conventional “1−1” surfactant pair, the “1−2” cationic−anionic surfactant pair exhibits unexpectedly weak aggregating ability. It is suggested that the hydrated volume of surfactant headgroup should be taken into consideration to better elucidate the self-assembly behavior of these “1−2” cationic−anionic surfactant mixtures.