Characterizing the rheology, slip, and velocity profiles of lamellar gel networks
Characterizing the rheology, slip, and velocity profiles of lamellar gel networks
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DOI：
10.1122/8.0000011
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发表时间：
2020-07-01
影响因子：
3.3
通讯作者：
Larson, Ronald G.
中科院分区：
文献类型：
--
作者：
Datta, Anukta;Tanmay, Velidanda S.;Larson, Ronald G.
作者报告了面霜、乳液和护发素等化妆品乳液中常见的伪三元“层状凝胶网络”的流变学和剪切流速曲线，该网络由阳离子表面活性剂山嵛基三甲基甲基硫酸盐、鲸蜡醇和硬脂醇的脂肪醇混合物以及水组成，表面活性剂/脂肪醇摩尔分数范围为 0.1 至 0.6，水质量分数为 85%-97%。高剪切稀化粘度在剪切速率的上升和下降过程中表现出滞后现象，凝胶在愈合并恢复其原始粘度之前“记住”其最高剪切力约 12 小时。这些材料表现出软玻璃状材料的流变特征（如软玻璃状流变学模型所描述），例如剪切滞后、不均匀速度梯度、类固体蠕变响应、阶跃应变实验中的幂律应力衰减以及在宽频率范围内相对于损耗模量的高储能模量，证实了其对小变形的近弹性响应。在稳态剪切实验中使用粒子图像测速（PIV），在剪切速率高于约0.01s（-1）时观察到从线速度分布到塞状分布的转变。 PIV 还揭示了宏观不均匀性，包括断裂面和剪切带的发展，流变学变得依赖于间隙，并显示出一些类固体摩擦的特征。
The authors report the rheology and shear flow velocity profiles of pseudo-ternary "lamellar gel networks" commonly found in cosmetic emulsions such as creams, lotions, and hair conditioners, consisting of the cationic surfactant behentrimonium methosulfate, a fatty alcohol mixture of cetyl and stearyl alcohol, and water at surfactant/fatty alcohol mole fractions ranging from 0.1 to 0.6 and water mass fractions of 85%-97%. The high shear-thinning viscosity shows hysteresis in up- and down-ramps of the shear rate, with the gel "remembering" its highest shear for around 12h before it heals and recovers its original viscosity. These materials exhibit rheological signatures characteristic of a soft glassy material (as described by the soft glassy rheology model) such as shear hysteresis, inhomogeneous velocity gradient, a solidlike creep response, power-law stress decay in step strain experiments, and high storage modulus relative to loss modulus over a wide range of frequencies, confirming its nearly elastic response for small deformations. Using particle image velocimetry (PIV) in steady shear experiments, a transition from a linear velocity profile to a pluglike profile was observed at shear rates above around 0.01s(-1). PIV also revealed macroscopic inhomogeneities including the development of fracture planes and shear bands, with rheology becoming gap-dependent and displaying some characteristics of solidlike friction.