Liquid Crystalline Blue Phases - Liquid Crystalline Functional Assemblies and Their Supramolecular Structures - page 110

Kitzerow et al. in 1993 formed blue phases of polymeric liquid crystal
monomers and polymerized these monomers while maintaining the blue-
phase structure, leading to a solid resin of fixed blue-phase structure [22].
Such a substance, although maintaining the blue-phase structure, provided
none of the dynamics of liquid crystal, since all the constituent molecules
were polymerized.
In 2002, Kikuchi et al. reported that the temperature range of the blue
phase can be expanded by several tens of degrees Celsius by forming a small
quantity of polymers at a ratio of 7-8 wt % within the blue phase. In this
system, referred to as “polymer-stabilized blue phases” (Fig. 11) [23], the
molecules retain their dynamics and exhibit rapid electro-optical responses
to an applied electric field. It is considered that the blue phase is stabi-
lized when the polymers formed within the blue phase are condensed into
disclinations, and the disclinations are then thermally stabilized. In 2005,
Yoshizawa, et al. synthesized T-shaped and dimeric liquid crystal molecules,
which broadened the temperature range of blue phases to 13 K [24] (Fig. 12).
It was suggested that this expanded temperature range is ascribable to the
biaxiality of the T-shaped liquid crystal molecules. Also in 2005, Coles et al.
reported that in dimer liquid crystals with large flexoelectricity, the tempera-
ture range of the blue phase was larger than 44 K [25] (Fig. 13). Flexoelectric-
Fig. 11 Phase diagram of polymer-stabilized blue phases and schematic illustration of
aggregation state of polymers [23]