Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706-1691, USA and Argonne National Laboratory, Argonne, Illinois 60349, USA.
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706-1691, USA.
Phys Rev Lett. 2013 Nov 27;111(22):227801. doi: 10.1103/PhysRevLett.111.227801. Epub 2013 Nov 26.
Common nematic oils, such as 5CB, experience planar anchoring at aqueous interfaces. When these oils are emulsified, this anchoring preference and the resulting topological constraints lead to the formation of droplets that exhibit one or two point defects within the nematic phase. Here, we explore the interactions of adsorbed particles at the aqueous interface through a combination of experiments and coarse-grained modeling, and demonstrate that surface-active particles, driven by elastic forces in the droplet, readily localize to these defect regions in a programmable manner. When droplets include two nanoparticles, these preferentially segregate to the two poles, thereby forming highly regular dipolar structures that could serve for hierarchical assembly of functional structures. Addition of sufficient concentrations of surfactant changes the interior morphology of the droplet, but pins defects to the interface, resulting in aggregation of the two particles.
常见的向列相液晶油，如 5CB，在水界面上经历面锚定。当这些油乳化时，这种锚定偏好和由此产生的拓扑约束导致形成在向列相中具有一个或两个点缺陷的液滴。在这里，我们通过实验和粗粒化建模相结合来探索吸附在水界面上的粒子的相互作用，并证明受液滴中弹性力驱动的表面活性粒子可以以可编程的方式容易地定位到这些缺陷区域。当液滴包含两个纳米颗粒时，它们优先分离到两个极点，从而形成高度规则的偶极子结构，可用于功能结构的分级组装。添加足够浓度的表面活性剂会改变液滴的内部形态，但会将缺陷固定在界面上，从而导致两个粒子的聚集。
