(443e) Stabilizing Blue Phase Liquid Crystal Under Spherical Confinement

At high level of chirality, cholesteric liquid crystals self-organize their helical structure into double twisted cylinders, which are interspersed by line defects. The double twisted cylinders organize into three-dimensional cubic lattice structures that can reflect the incident light in the wavelength range of visible spectrum. These structures, that emerge between cholesteric and isotropic phases, are known as cholesteric “Blue Phases, BPs”. The blue phase liquid crystals are, however, thermodynamically stable over a narrow temperature range. Introducing reactive mesogens into the defect structures followed by polymerization has been proven as a successful strategy to expand the stability temperature of BPs. While the bulk properties of the polymer-stabilized blue phases have extensively been explored, the effect of geometrical confinement on the stabilized blue phases remains as an open question. Our experimental and computational studies show that confining the polymer-stabilized blue phases within the spherical droplets significantly influences their internal structures, reflected color and stability temperature. Using a super-resolution confocal laser scanning microscopy, we have been able to image the periodic structure of the double twisted cylinders in real space. We have found that the orientation of the lattice structures in the stabilized BP droplets can be manipulated by controlling the droplet size and polymerization time, which can be exploited to achieve monodomain blue phase structures. These new findings offer tremendous opportunities for engineering optical devices based on the high chirality liquid crystals.