Interfacial fluid rheology of soft particles

In situ interfacial rheology and numerical simulations are used to investigate microgel monolayers in a wide range of packing fractions, ζ2D. The heterogeneous particle compressibility determines two flow regimes characterized by distinct master curves. To mimic the microgel architecture and reproduce experiments, an interaction potential combining a soft shoulder with the Hertzian model is introduced. In contrast to bulk conditions, the elastic moduli vary nonmonotonically with ζ2D at the interface, confirming long-sought predictions of reentrant behavior for Hertzian-like systems.

本研究借助原位界面流变学（in situ interfacial rheology）与数值模拟方法，对宽范围二维填充率（ζ2D）下的微凝胶单层（microgel monolayers）体系开展了系统探究。非均匀颗粒压缩性决定了两类具有显著差异化主曲线特征的流动区域。为模拟微凝胶结构并复现实验结果，本研究引入了一种结合软肩与赫兹模型（Hertzian model）的相互作用势。与体相条件不同，界面处的弹性模量随二维填充率呈非单调变化，验证了赫兹类体系长期以来学界追寻的重入行为预测。