nn5b07379_si_001.pdf (528.06 kB)
Reversible Nanoparticle Cubic Lattices in Blue Phase Liquid Crystals
journal contribution
posted on 2016-02-22, 00:00 authored by Mohamed
Amine Gharbi, Sabine Manet, Julien Lhermitte, Sarah Brown, Jonathan Milette, Violeta Toader, Mark Sutton, Linda RevenBlue
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.