论文标题
肿胀的胶束吸附抑制可能会导致活性液滴的多稳定性
Adsorption inhibition by swollen micelles may cause multistability in active droplets
论文作者
论文摘要
实验表明，在大部分表面活性剂溶液中接受胶束溶解的微螺旋体可能会自发地激发Marangoni流动和自行性。令人惊讶的是，即使超过临界胶束浓度并且应饱和，也会出现自我刺激。为了解释这一点，我们提出了一个基于两个基本假设的溶解活性液滴的新型模型：（a）溶解化的产物可以抑制表面活性剂的吸附； （b）溶解化阻止在液滴界面形成表面活性剂分子的单层。我们使用数值仿真和渐近方法来证明我们的模型确实具有自发的液滴自我推测。我们的主要发现是，在轴对称流和浓度场的情况下，对于物理参数的相同值，两种质量上不同类型的液滴行为可能是稳定的：稳定的自我刺激和稳定的对称泵。尽管在没有轴向对称性的情况下不能保证这些稳定机制的稳定性，但我们认为它们将保留其各自的稳定流形在完全3D问题的相空间中。
Experiments indicate that microdroplets undergoing micellar solubilization in the bulk of surfactant solution may excite Marangoni flows and self-propel spontaneously. Surprisingly, self-propulsion emerges even when the critical micelle concentration is exceeded and the Marangoni effect should be saturated. To explain this, we propose a novel model of a dissolving active droplet that is based on two fundamental assumptions: (a) products of the solubilization may inhibit surfactant adsorption; (b) solubilization prevents the formation of a monolayer of surfactant molecules at the droplet interface. We use numerical simulations and asymptotic methods to demonstrate that our model indeed features spontaneous droplet self-propulsion. Our key finding is that in the case of axisymmetric flow and concentration fields, two qualitatively different types of droplet behavior may be stable for the same values of the physical parameters: steady self-propulsion and steady symmetric pumping. Although stability of these steady regimes is not guaranteed in the absence of axial symmetry, we argue that they will retain their respective stable manifolds in the phase space of a fully 3D problem.
