Towards an analytical description of active microswimmers in clean and in surfactant-covered drops
Towards an analytical description of active microswimmers in clean and in surfactant-covered drops
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DOI：
10.1140/epje/i2020-11980-9
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发表时间：
2020-09-11
影响因子：
1.8
通讯作者：
Daddi-Moussa-Ider, Abdallah
中科院分区：
文献类型：
--
作者：
Sprenger, Alexander R.;Shaik, Vaseem A.;Daddi-Moussa-Ider, Abdallah
几何约束在生物界中经常遇到，并强烈影响粘性流中活性悬浮液的稳定性、拓扑结构和输运性质。基于远场分析模型，从理论上研究了自推进微游泳器在清洁粘性液滴或表面活性剂均匀分布液滴中的低雷诺数运动.由表面活性剂引起的界面粘性应力由公认的Boussinesq-Scriven本构流变模型描述。此外，活性剂表示的力偶极子和由此产生的流体介导的流体动力学之间的耦合的游泳者和限制下降进行了研究。我们发现，表面活性剂的存在下，显着改变封装的游泳者的动力学，通过提高其重定向。引入了液滴内部Stokeslet流和偶极流奇点的速度图像的精确解，并用谐波分量的无穷级数表示。我们的研究结果提供了有用的见解的指导原则，用于控制有限的活性物质系统，并支持利用合成的microswimmer驱动液滴的目标，有针对性的药物输送应用。
Geometric confinements are frequently encountered in the biological world and strongly affect the stability, topology, and transport properties of active suspensions in viscous flow. Based on a far-field analytical model, the low-Reynolds-number locomotion of a self-propelled microswimmer moving inside a clean viscous drop or a drop covered with a homogeneously distributed surfactant, is theoretically examined. The interfacial viscous stresses induced by the surfactant are described by the well-established Boussinesq-Scriven constitutive rheological model. Moreover, the active agent is represented by a force dipole and the resulting fluid-mediated hydrodynamic couplings between the swimmer and the confining drop are investigated. We find that the presence of the surfactant significantly alters the dynamics of the encapsulated swimmer by enhancing its reorientation. Exact solutions for the velocity images for the Stokeslet and dipolar flow singularities inside the drop are introduced and expressed in terms of infinite series of harmonic components. Our results offer useful insights into guiding principles for the control of confined active matter systems and support the objective of utilizing synthetic microswimmers to drive drops for targeted drug delivery applications.