First anionic micelle with unusually long lifetime: self-assembly of fluorocarbon-hydrocarbon hybrid surfactant.
First anionic micelle with unusually long lifetime: self-assembly of fluorocarbon-hydrocarbon hybrid surfactant.
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第一个具有异常长寿命的阴离子胶束：氟碳烃杂化表面活性剂的自组装。
DOI：
10.1021/ja0178564
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发表时间：
2002
影响因子：
15
通讯作者：
N. Yoshino
中科院分区：
文献类型：
--
作者：
Y. Kondo;Haruhiko Miyazawa;H. Sakai;M. Abe;N. Yoshino
用~（19）FNMR和~ 1HNMR研究了氟碳-碳氢杂化表面活性剂在氘氧化物中单体态和胶束态之间的交换。表面活性剂中的CF 3基团给出了两种对应于单体和胶束状态的19 F NMR信号，表明在NMR时间尺度上缓慢的表面活性剂交换。通过对信号的线形分析，估算出胶束的寿命（τ_（umic））为2.0ms，比一般表面活性剂胶束的寿命长102 ~ 103倍。脉冲梯度自旋回波（PGSE）实验表明，混合表面活性剂形成相当小的胶束的流体动力学半径为0.6 nm。相反，在没有观察到缓慢的表面活性剂交换的较高浓度下，胶束半径增加至1.1 nm。胶束中表面活性剂分子之间的交错将有助于异常长的寿命，换句话说，NMR时间尺度上的缓慢表面活性剂交换。
The exchange of a fluorocarbon-hydrocarbon hybrid surfactant between monomer and micelle states in deuterium oxide has been investigated through 19F NMR and 1H NMR experiments. The CF3 group in the surfactant gives two kinds of 19F NMR signals corresponding to the monomer and micelle states, indicating slow surfactant exchange on NMR time scale. The lifetime (taumic) of micelle, estimated by line shape analysis of the signals, is 2.0 ms at cmc, 102 to 103 times longer than that of general surfactant micelles. Pulsed-gradient spin-echo (PGSE) experiments show that the hybrid surfactant forms considerably small micelles with a hydrodynamic radius of 0.6 nm. In contrast, at a higher concentration where no slow surfactant exchange is observed, the micelle radius increases to 1.1 nm. The interdigitation between the surfactant molecules in the micelle will contribute to the unusually long lifetime, in other words, slow surfactant exchange on the NMR time scale.