Chemical Engineering Department, Manhattan College, Riverdale, NY, USA.
Int J Cosmet Sci. 2021 Apr;43(2):246-253. doi: 10.1111/ics.12689. Epub 2021 Mar 18.
The purpose of this study is to understand the impact of the cationic polymer merquat on the rheological behavior of the mixed surfactant system of sodium lauryl ether sulfate (SLES) and cocamidopropyl betaine (CapB) as well as the impact of varying formulation conditions on the wet lubrication performance of the SLES-CapB-Merquat system.
Rotation mechanical Rheometry was used to study the rheological response of the SLES-CapB-Merquat systems. Frequency sweeps were conducted to analyze the rheological properties of the system at low frequency ranges and bulk viscosity of the system was studied at high shear rates at varying salt and polymer concentrations. Wet combing tests and hair friction tests were run on the Dia-stron MTT175 flexible miniature tensile tester in order to evaluate the conditioning effects of the different formulations.
The SLES-CapB system on its own exhibits very little viscosity. The bulk rheology results show that the addition of Merquat enhances the viscosity and viscoelastic properties of the SLES-CapB-Merquat system indicating the presence of electrostatic interactions between the surfactant and polyelectrolyte. Addition of salt had a significant impact on the system's rheological response due to the charge screening effect of salt. Wet combing force data indicate that the charged polyelectrolyte binds to the hair substrate resulting in reduced combing force values after the product was applied. The addition of silicone oil to the formulation seemed to greatly enhance the conditioning effect of the formulation.
The charge interactions between SLES, CapB and Merquat results in the formation of an integrated gel like network, thus building the viscosity of the system. Variation of parameters like polymer and salt concentration has the potential to modify the bulk rheological properties and consequently the wet lubrication properties of the system.
本研究旨在了解阳离子聚合物 merquat 对月桂醚硫酸酯钠（SLES）和椰油酰胺丙基甜菜碱（CapB）混合表面活性剂体系流变行为的影响，以及不同配方条件对 SLES-CapB-Merquat 体系湿润滑性能的影响。
采用旋转机械流变仪研究 SLES-CapB-Merquat 体系的流变响应。进行频率扫描以分析系统在低频范围内的流变性能，并在不同盐和聚合物浓度下研究系统在高剪切速率下的整体粘度。在 Dia-stron MTT175 柔性微型拉伸试验机上进行湿梳理试验和头发摩擦试验，以评估不同配方的调理效果。
单独的 SLES-CapB 体系本身几乎没有粘度。整体流变学结果表明，添加 Merquat 增强了 SLES-CapB-Merquat 体系的粘度和粘弹性，表明表面活性剂和聚电解质之间存在静电相互作用。盐的添加对系统的流变响应有显著影响，这是由于盐的电荷屏蔽效应。湿梳理力数据表明，带电的聚电解质与头发基质结合，导致产品使用后梳理力值降低。配方中添加硅油似乎极大地增强了配方的调理效果。
SLES、CapB 和 Merquat 之间的电荷相互作用导致形成集成凝胶状网络，从而构建系统的粘度。参数如聚合物和盐浓度的变化有可能改变系统的整体流变性能，从而改变其湿润滑性能。
