Yusof Nor Saadah M, Razak Norazizah A, Khan M Niyaz
Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
J Oleo Sci. 2013;62(5):257-69. doi: 10.5650/jos.62.257.
A semi empirical kinetic (SEK) method has been used to determine the ratio of cetyltrimethylammonium bromide (CTABr) micellar binding constants of counterion X⁻ and Br⁻ (a reference counterion), i.e. K(X)/K(Br) (=R(X)(Br)). The values of K(X) and K(Br) have been derived from the kinetic parameters obtained in the presence spherical/non-spherical and spherical micelles, respectively. This rather new method gives the respective mean values of R(X)(Br) as 45±2, 25±3, 4.7±0.6 and 119±10 for X=2,4-, 2,5-, 2,6- and 3,4-Cl₂C₆H₃CO₂⁻ (Cl₂Bz'Na). Literature lacks the report on the values of R(X)(Br) for all X except for X=2,6-Cl₂C₆H₃CO₂⁻ (2,6-Cl2Bz'⁻) for which the reported value is 5.0. Rheological properties, such as shear thinning behavior, reveal indirectly the presence of wormlike micelles (WM) in the CTABr micellar solutions containing MX for all X except X=2,6-Cl₂Bz'⁻. The micelles remain spherical within [2,6-Cl₂Bz'⁻] range 0.01-0.34 M at 0.015 M CTABr. The maxima of the plots of zero shear viscosity, η₀, (obtained from the initial plateau region of flow curves, i.e. η vs. γ curve) vs. [MX] (MX=2,4-, 2,5- and 3,4-Cl₂Bz'Na) at 0.015 M CTABr also support indirectly the presence of linear, entangled and branched WM.
一种半经验动力学（SEK）方法已被用于测定抗衡离子X⁻与Br⁻（一种参比抗衡离子）的十六烷基三甲基溴化铵（CTABr）胶束结合常数之比，即K(X)/K(Br)（=R(X)(Br)）。K(X)和K(Br)的值分别从在球形/非球形和球形胶束存在下获得的动力学参数推导得出。这种相当新的方法给出了X = 2,4 -、2,5 -、2,6 -和3,4 - Cl₂C₆H₃CO₂⁻（Cl₂Bz'Na）时R(X)(Br)的各自平均值为45±2、25±3、4.7±0.6和119±10。文献中除了X = 2,6 - Cl₂C₆H₃CO₂⁻（2,6 - Cl2Bz'⁻）外，缺少所有X的R(X)(Br)值的报道，对于X = 2,6 - Cl₂C₆H₃CO₂⁻，报道值为5.0。流变学性质，如剪切变稀行为，间接揭示了除X = 2,6 - Cl₂Bz'⁻外，含MX的CTABr胶束溶液中存在蠕虫状胶束（WM）。在0.015 M CTABr时，胶束在[2,6 - Cl₂Bz'⁻]范围0.01 - 0.34 M内保持球形。0.015 M CTABr时零剪切粘度η₀（从流动曲线的初始平稳区域，即η对γ曲线获得）对[MX]（MX = 2,4 -、2,5 -和3,4 - Cl₂Bz'Na）的曲线最大值也间接支持了线性、缠结和分支WM的存在。
