Wang Xiaoguang, Miller Daniel S, de Pablo Juan J, Abbott Nicholas L
Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States.
Institute for Molecular Engineering, University of Chicago, 5801 South Ellis Avenue Chicago, Illinois 60637, United States.
Adv Funct Mater. 2014 Oct 22;24(39):6219-6226. doi: 10.1002/adfm.201400911.
The spontaneous positioning of colloids on the surfaces of micrometer-sized liquid crystalline droplets and their subsequent polymerization offers the basis of a general and facile method for the synthesis of patchy microparticles. The existence of multiple local energetic minima, however, can generate kinetic traps for colloids on the surfaces of the liquid crystal (LC) droplets and result in heterogeneous populations of patchy microparticles. To address this issue, here we demonstrate that adsorbate-driven switching of the internal configurations of LC droplets can be used to sweep colloids to a single location on the LC droplet surfaces, thus resulting in the synthesis of homogeneous populations of patchy microparticles. The surface-driven switching of the LC can be triggered by addition of surfactant or salts, and permits the synthesis of dipolar microparticles as well as "Janus-like" microparticles. By using magnetic colloids, we illustrate the utility of the approach by synthesizing magnetically-responsive patchy microdroplets of LC with either dipolar or quadrupolar symmetry that exhibit distinct optical responses upon application of an external magnetic field.
胶体在微米级液晶微滴表面的自发定位及其随后的聚合反应为合成斑状微粒提供了一种通用且简便的方法基础。然而，多个局部能量极小值的存在会在液晶（LC）微滴表面为胶体产生动力学陷阱，并导致斑状微粒群体的异质性。为了解决这个问题，我们在此证明，吸附质驱动的LC微滴内部构型切换可用于将胶体扫至LC微滴表面的单个位置，从而合成均匀的斑状微粒群体。LC的表面驱动切换可通过添加表面活性剂或盐来触发，并允许合成偶极微粒以及“类 Janus”微粒。通过使用磁性胶体，我们通过合成具有偶极或四极对称性的磁性响应性LC斑状微滴来说明该方法的实用性，这些微滴在施加外部磁场时表现出不同的光学响应。
