Reversible Nanoparticle Cubic Lattices in Blue Phase Liquid Crystals

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• 作者：Mohamed Amine Gharbi ; Sabine Manet ; Julien Lhermitte ; Sarah Brown ; Jonathan Milette ; Violeta Toader ; Mark Sutton ; Linda Reven
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：March 22, 2016
• 年：2016
• 卷：10
• 期：3
• 页码：3410-3415
• 全文大小：367K
• ISSN：1936-086X

文摘

Blue phases (BPs), a distinct class of liquid crystals (LCs) with 3D periodic ordering of double twist cylinders involving orthogonal helical director twists, have been theoretically studied as potential templates for tunable colloidal crystals. Here, we report the spontaneous formation of thermally reversible, cubic crystal nanoparticle (NP) assemblies in BPs. Gold NPs, functionalized to be highly miscible in cyanobiphenyl-based LCs, were dispersed in BP mixtures and characterized by polarized optical microscopy and synchrotron small-angle X-ray scattering (SAXS). The NPs assemble by selectively migrating to periodic strong trapping sites in the BP disclination lines. The NP lattice, remarkably robust given the small particle size (4.5 nm diameter), is commensurate with that of the BP matrix. At the BP I to BP II phase transition, the NP lattice reversibly switches between two different cubic structures. The simultaneous presence of two different symmetries in a single material presents an interesting opportunity to develop novel dynamic optical materials.