A cationic fluorocarbon surfactant DEFUMACl and its mixed systems with cationic surfactants: F-19 NMR and surface tension study

作者：Dong Shuli; Li Xin; Xu Guiying^*; Hoffmann Heinz

来源：Journal of Physical Chemistry B, 2007, 111(21): 5903-5910.

DOI：10.1021/jp0705469

A cationic fluorocarbon surfactant system of diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMACl) and both mixed systems of DEFUMACl/cationic dodecyltrimethylammonium chloride (DTACl) and DEFUMACl/cationic Gemini copolymer was investigated by F-19 NMR spectroscopy and surface tension measurements. The critical micelle concentration (cmc) of DEFUMACl by F-19 NMR is about 3.40 mmol/L, which is completely consistent with that obtained by the surface tension method. The studies of salt and temperature on the cmc values of DEFUMACl suggest that both salt addition and temperature increase decrease the cmc values of DEFUMACl. F-19 NMR measurements provide much richer information on both mixed systems. For the DEFUMACl-DTACl system, two break points were observed with increased total surfactant concentration. The first break point means the DEFUMACl and DTACl mixed micelles and the second one implies the individual DEFUMACl micelles. Results of F-19 NMR and surface tension measurements for DEFUMACl/cationic Gemini copolymer mixtures show three peculiar break points, corresponding to the critical association concentration (cac) of DEFUMACl, the concentration where cationic Gemini copolymer molecules become saturated by DEFUMACl micelles, and the concentration where DEFUMACl micelles and cationic Gemini copolymer coexist. These peculiar points in the cationic-fluorocarbon and cationic-copolymer systems were first reported by F-19 NMR and surface tension measurements. These results should broaden the useful information for a better understanding of the mechanism of interaction and the behavior of surfactant-polymer mixtures.

• 出版日期2007-5-31
• 单位山东大学