Sachin K M, Karpe Sameer A, Singh Man, Bhattarai Ajaya
School of Chemical Sciences, Central University of Gujarat, Gandhinagar, India.
Department of Chemistry, Tribhuvan University, M. M. A. M. Campus, Biratnagar, Nepal.
R Soc Open Sci. 2019 Mar 27;6(3):181979. doi: 10.1098/rsos.181979. eCollection 2019 Mar.
The micellar property of mixed surfactant systems, cationic (dodecyltrimethylammonium bromide, DTAB) and anionic (sodium dodecylsulfate, SDS) surfactants with variable molar ratios in aqueous system has been reported by using surface tension and conductivity measurements at = 293.15, 298.15 and 303.15 K. DTAB concentrations are varied from 1.0 × 10 to 3 × 10 mol l in 1.0 × 10 mol l SDS solution while the SDS concentration is varied from 1.0 × 10 to 1.5 × 10 mol l in approximately 5.0 × 10 mol l DTAB, so that such concentrations of DTAB-SDS (DTAB-rich) and SDS-DTAB (SDS-rich) solutions were chosen 3 : 1 ratio. The critical micellar concentration, as well as surface and thermodynamic properties for DTAB-rich and SDS-rich solutions, were evaluated by the surface tension () and conductivity () methods. The pseudo phase separation model was coupled with the dissociated Margules model for synergism. The Krafft temperature behaviour and optical analysis of mixed surfactants are studied using conductivity and UV-Vis spectroscopy, respectively. The dispersibility and stability of DTAB-rich and SDS-rich solutions with and without dyes (2.5 × 10 mol l of methyl orange and methylene blue) are carried out by using UV-Vis spectroscopy and dynamic light scattering.
通过在293.15K、298.15K和303.15K下测量表面张力和电导率，报道了阳离子（十二烷基三甲基溴化铵，DTAB）和阴离子（十二烷基硫酸钠，SDS）表面活性剂在水体系中不同摩尔比的混合表面活性剂体系的胶束性质。在1.0×10⁻³mol/L SDS溶液中，DTAB浓度从1.0×10⁻⁴mol/L变化到3×10⁻⁴mol/L，而在大约5.0×10⁻⁴mol/L DTAB中，SDS浓度从1.0×10⁻⁴mol/L变化到1.5×10⁻⁴mol/L，从而选择了DTAB-SDS（富含DTAB）和SDS-DTAB（富含SDS）溶液的3:1比例。通过表面张力（γ）和电导率（κ）方法评估了富含DTAB和富含SDS溶液的临界胶束浓度以及表面和热力学性质。将假相分离模型与解离的Margules模型相结合以研究协同作用。分别使用电导率和紫外可见光谱研究了混合表面活性剂的克拉夫特温度行为和光学分析。通过紫外可见光谱和动态光散射研究了富含DTAB和富含SDS溶液在有无染料（2.5×10⁻⁵mol/L的甲基橙和亚甲基蓝）情况下的分散性和稳定性。
