近日，美国加州大学的Zvonimir Dogic&M. Cristina Marchetti及其研究团队取得一项新进展。他们揭示了活性界面的不对称波动和自折叠。相关研究成果已于2024年12月10日在国际知名学术期刊《美国科学院院刊》上发表。

该研究团队研究了将被动流体与基于微管的活性流体，分隔开的界面结构和动力学。类似湍流的活性流动驱动了巨大的界面波动，这些波动在正曲率和负曲率区域之间表现出明显的不对称性。

通过实验、数值模拟和理论分析，研究人员揭示了界面如何打破基本弯曲不稳定性的空间对称性，从而产生导致界面不对称波动的局部涡流。

界面变形的程度随着活性的增强而增加——在高活性极限下，界面会自我折叠，使被动液滴内陷，并生成一种类似泡沫的相，其中活性流体被被动液滴穿孔。

这些结果展示了活性应力如何控制柔软、可变形和可重构的，液-液界面的结构与动力学及破裂过程。

附：英文原文

Title: Asymmetric fluctuations and self-folding of active interfaces

Author: Zhao, Liang, Gulati, Paarth, Caballero, Fernando, Kolvin, Itamar, Adkins, Raymond, Marchetti, M. Cristina, Dogic, Zvonimir

Issue&Volume: 2024-12-10

Abstract: We study the structure and dynamics of the interface separating a passive fluid from a microtubule-based active fluid. Turbulent-like active flows power giant interfacial fluctuations, which exhibit pronounced asymmetry between regions of positive and negative curvature. Experiments, numerical simulations, and theoretical arguments reveal how the interface breaks up the spatial symmetry of the fundamental bend instability to generate local vortical flows that lead to asymmetric interface fluctuations. The magnitude of interface deformations increases with activity: In the high activity limit, the interface self-folds invaginating passive droplets and generating a foam-like phase, where active fluid is perforated with passive droplets. These results demonstrate how active stresses control the structure, dynamics, and break-up of soft, deformable, and reconfigurable liquid–liquid interfaces.

DOI: 10.1073/pnas.2410345121

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2410345121