Tsujinoue Hiroaki, Kobayashi Yusei, Arai Noriyoshi
Department of Mechanical Engineering, Keio University, Yokohama 223-8522, Japan.
Langmuir. 2020 Sep 15;36(36):10690-10698. doi: 10.1021/acs.langmuir.0c01359. Epub 2020 Aug 30.
The effects of the chemical nature of an interface are one of the key parameters which can affect self-assembly and rheological behavior. To date, several studies have reported self-assembled structures and rheological behaviors in the development of various functional materials. In this study, we investigated the self-assembly and viscosity behavior of aqueous surfactant solutions confined in three types of Janus amphiphilic nanotubes (JANTs), which have two, four, and eight sequential domains, respectively, using molecular simulation. We found that the viscosity behavior depends on the surfactant concentration and the chemical nature of the wall surface. For instance, although the concentration levels of the surfactants are the same ( = 10%), completely different viscosity behaviors were observed in the two sequential domains (Newtonian-like) and the four and eight sequential domains (strong shear-thinning) of the JANTs. Our simulations demonstrated how the rheological properties of aqueous surfactant solutions, including viscosity and velocity profiles, can be controlled by the chemical nature of the JANT wall surface, effect of confinement, and their self-assembly structures. Considering the foregoing, we hope that our study offers new knowledge on nanofluid systems.
界面化学性质的影响是能够影响自组装和流变行为的关键参数之一。迄今为止，已有多项研究报道了各种功能材料开发过程中的自组装结构和流变行为。在本研究中，我们使用分子模拟研究了分别包含两个、四个和八个连续区域的三种类型的Janus两亲性纳米管（JANTs）中受限的表面活性剂水溶液的自组装和粘度行为。我们发现粘度行为取决于表面活性剂浓度和壁面的化学性质。例如，尽管表面活性剂的浓度水平相同（= 10%），但在JANTs的两个连续区域（类牛顿流体）以及四个和八个连续区域（强剪切变稀）中观察到了完全不同的粘度行为。我们的模拟展示了表面活性剂水溶液的流变性质，包括粘度和速度分布，如何通过JANT壁面的化学性质、受限效应及其自组装结构来控制。考虑到上述情况，我们希望我们的研究能为纳米流体系统提供新的知识。
