Nikoubashman Arash, Bianchi Emanuela, Panagiotopoulos Athanassios Z
Institute of Theoretical Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, A-1040 Vienna, Austria.
Soft Matter. 2015 May 21;11(19):3767-71. doi: 10.1039/c5sm00281h.
We investigate the self-assembly of colloidal Janus particles under shear flow by employing hybrid molecular dynamics simulations that explicitly take into account hydrodynamic interactions. Under quiescent conditions, the amphiphilic colloids form spherical micellar aggregates of different sizes, where the solvophobic hemispheres are directed towards the core and the solvophilic caps are exposed to the solvent. When sufficiently strong shear is applied, the micelles disaggregate with a consequent decay of the average cluster size. Nonetheless, we find an intermediate shear rate regime where the balance between rearrangement and dissociation favors the growth of the aggregates. Additionally, our simulations show that clusters composed of either 6 or 13 particles are the most stable towards the shear flow due to their high geometric symmetry. Our findings open up a new range of applications for Janus particles, ranging from biotechnology to sensor systems.
我们通过采用明确考虑流体动力学相互作用的混合分子动力学模拟，研究了剪切流作用下胶体Janus粒子的自组装过程。在静态条件下，两亲性胶体形成不同尺寸的球形胶束聚集体，其中疏溶剂半球指向核心，亲溶剂帽暴露于溶剂中。当施加足够强的剪切力时，胶束会解体，平均簇尺寸随之减小。尽管如此，我们发现了一个中间剪切速率范围，其中重排和解离之间的平衡有利于聚集体的生长。此外，我们的模拟表明，由6个或13个粒子组成的簇由于其高几何对称性，对剪切流最为稳定。我们的研究结果为Janus粒子开辟了一系列新的应用领域，从生物技术到传感系统。
