title: Reversible Nanoparticle Cubic Lattices in Blue Phase Liquid Crystals.
abstract: 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.
authors.affiliation: Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada.|Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada.
authors.forename: Mohamed Amine
authors.initials: MA
authors.lastname: Gharbi
authors.affiliation: Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada.|Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada.
authors.forename: Sabine
authors.initials: S
authors.lastname: Manet
authors.affiliation: Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada.
authors.forename: Julien
authors.initials: J
authors.lastname: Lhermitte
authors.affiliation: Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada.|Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Brown
authors.affiliation: Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Milette
authors.affiliation: Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada.
authors.forename: Violeta
authors.initials: V
authors.lastname: Toader
authors.affiliation: Department of Physics, McGill University , Montreal, Québec H3A2T8, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Sutton
authors.affiliation: Centre for Self-Assembled Chemical Structures (CSACS/CRMAA), Department of Chemistry, McGill University , Montreal, Québec H3A0B8, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Reven
keywords: blue phase; colloidal crystal; liquid crystal; nanoparticles