阳离子碳氟表面活性剂研究I:水溶液中的胶束特性及生长

Study on Cationic Fluorocarbon Surfactants I. Growth and Properties of Micelles in Aqueous Solution

利用动态光散射(DynamicLightScattering,DLS)、瞬态电双折射(TransientElectricBirefringence,TEB)和粘度测定方法研究了部分氟代阳离子表面活性剂氟代-2-羟基十一烷基二乙羟基甲基氯化铵(diethanolheptadecafluoro-2-undecanolmethylammoniumchloride,C8F17CH2CH(OH)CH2NCH3(C2H4OH)2Cl,DEFUMACl)水溶液的胶束化特性.结果表明:DEFUMACl的临界胶束浓度cmc为3.8mmol?L-1.稀溶液中随着DEFUMACl浓度的增加或者无机盐NaCl的加入,DEFUMACl胶束由球形向棒状转变,其转变浓度,即第二临界胶束浓度(cmcII)为0.2mol?L-1;电导测定的反离子(Cl-)结合度为0.72.利用球形和棒状胶束模型确定的DEFUMACl胶束聚集数分别为45和335.

The micellar properties such as critical micelle concentration （cmc）, counterion binding, and the micellar growth of cationic fluorocarbon surfactant, diethanolheptadecafluoro-2-undecanol methylammonium chloride （DEFUMACl）, were studied by dynamic light scattering （DLS）, transient electric birefringence （TEB） and viscosity measurements. The micellar growth of DEFUMACl was induced by increasing DEFUMACl concentration and adding inorganic salt （NaCl）. The cmc of DEFUMACI is 3.8 mmol·L^-1. The results clearly showed that the spherical micelles were elongated to rod-like micelles by addition of salt in a dilute DEFUMACl solution or increasing DEFUMACl concentration. The second critical micelle concentration （cinch） was determined to be 0.2 mol·L^-1 by conductivity measurements. The aggregation numbers of spherical and rod-like micelles were calculated to be 45 and 335, respectively.