G. Heppke, H.-S. Kitzerow, D. Lötzsch and C. Papenfuss
Blue phase mixtures exhibiting low fractions of a chiral compound:
Experimental observation of some unusual properties
Liquid Crystals 8, 1990, 407-418
We have used chiral compounds with very high helical twisting power as
components in induced-cholesteric mixtures in order to obtain new blue
phase systems. In one of these mixtures an unusual large blue phase
temperature range of 10K was observed. The lattice constant of BPI in
this system increases strongly with increasing temperature, a
behaviour observed for the first time. The threshold voltage for the
field induced BP/cholesteric phase transition in this mixture
decreases with increasing temperature. Thus the reentrant phase
sequence cholesteric phase - blue phase - cholesteric phase -
isotropic phase can be observed with increasing temperature if an
electric field is applied to the sample.