Interfacial mechanisms in active emulsions
Interfacial mechanisms in active emulsions
复制标题
DOI：
10.1039/c4sm00550c
复制
发表时间：
2014-01-01
期刊：
影响因子：
3.4
通讯作者：
Bahr, Christian
中科院分区：
文献类型：
--
作者：
Herminghaus, Stephan;Maass, Corinna C.;Bahr, Christian
活性乳状液，即液滴执行自行式运动的乳状液，在模拟浮游植物和细菌菌落等生物种群中的集体现象方面具有极大的兴趣，但在远离热平衡的系统中也用于实验研究流变学、图案形成和相变。对于这种体系的燃料，涉及稳定乳化液的表面活性剂的分子过程是一个简单的概念。我们概述并比较了两种不同类型的反应，一种是对表面活性剂分子进行化学修饰，另一种是将它们转变为不同的胶体状态。虽然在第一种情况下对称性破缺遵循标准的线性不稳定性，但第二种情况被证明是更复杂的。根据溶解途径的不同，要么存在内在的非线性不稳定性，要么根本没有对称性破缺(因此没有运动)。
Active emulsions, i.e., emulsions whose droplets perform self-propelled motion, are of tremendous interest for mimicking collective phenomena in biological populations such as phytoplankton and bacterial colonies, but also for experimentally studying rheology, pattern formation, and phase transitions in systems far from thermal equilibrium. For fuelling such systems, molecular processes involving the surfactants which stabilize the emulsions are a straightforward concept. We outline and compare two different types of reactions, one which chemically modifies the surfactant molecules, the other which transfers them into a different colloidal state. While in the first case symmetry breaking follows a standard linear instability, the second case turns out to be more complex. Depending on the dissolution pathway, there is either an intrinsically nonlinear instability, or no symmetry breaking at all (and hence no locomotion).