Abstract
We have found the new types of photonic liquid crystal, SmBPIso phase,which shows the uniform isotropic iridescent color strongly dependent onthe concentration, chirality and temperature for the first time. SmBPIso has both the finite local order parameter of the helix of the orientation and the smectic layer simultaneously, but spontaneously achieves complete isotropic nature in optical wave-length without any characteristic discontinuity in mesoscopic length scales. It was confirmed by visco-elastic measurement that the SmBPIso should be originated from the anomalous softening of the smectic layers due to the freezing effect on the molecular fluctuation induced by the introduction of the connection of the molecules in chiral twin and monomer commensurate mixture. We expected that the random distribution of the locally distinct helix in 3-dimensional space can be stabilized by the apparent elastic long-range interaction "field" produced by the deformation of the smectic order together with helixes themselves.
