D'Adamo G, Marenduzzo D, Micheletti C, Orlandini E
SISSA, International School for Advanced Studies, via Bonomea 265, I-34136 Trieste, Italy.
SUPA, School of Physics and Astronomy, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom.
Phys Rev Lett. 2015 May 1;114(17):177801. doi: 10.1103/PhysRevLett.114.177801. Epub 2015 Apr 30.
We study how dispersions of colloidal particles in a cholesteric liquid crystal behave under a time-dependent electric field. By controlling the amplitude and shape of the applied field wave, we show that the system can be reproducibly driven out of equilibrium through different kinetic pathways and navigated through a glassylike free energy landscape encompassing many competing metastable equilibria. Such states range from simple Saturn rings to complex structures featuring amorphous defect networks, or stacks of disclination loops. A nonequilibrium electric field can also trigger the alignment of particles into columnar arrays, through defect-mediated force impulses, or their repositioning within a plane. Our results are promising in terms of providing new avenues towards controlled patterning and self-assembly of soft colloid-liquid crystal composite materials.
我们研究了胆甾型液晶中胶体颗粒的分散体在随时间变化的电场作用下的行为。通过控制外加电场波的幅度和形状，我们表明该系统可以通过不同的动力学途径被可重复地驱动到非平衡状态，并在包含许多相互竞争的亚稳平衡的类玻璃自由能景观中导航。这些状态范围从简单的土星环到具有无定形缺陷网络或位错环堆叠的复杂结构。非平衡电场还可以通过缺陷介导的力脉冲触发颗粒排列成柱状阵列，或者使它们在平面内重新定位。我们的研究结果在为软胶体 - 液晶复合材料的可控图案化和自组装提供新途径方面很有前景。
