Abstract
We have investigated the collective fluctuation in the chiral smectic phases of main‐chain polyesters having a mesogenic p,p′‐dibenzoate unit via dielectric and dynamic electrooptical measurements. A relaxation due to the Goldstone mode was observed at several tens of Hz in the chiral smectic C (SmC*) phase in both measurements, where another relaxation associated with the soft mode was also confirmed around the SmA–SmC* phase transition temperature. Although the mesogens are linked together in a main‐chain liquid crystalline polymer, the observed soft mode is associated with the tilt fluctuation of the average direction of the mesogens.
Acknowledgements
We thank Mr. Inada, Mr. Hohrai, Miss Toyota, Mr. Kon, and Mr. Sagano for experimental assistance. K. H. wishes to acknowledge valuable discussions with Prof. Lubensky in the FLC conference held at Brest. This work was supported by the Grant‐in Aid for Scientific Research (#17550169) and the ‘Academic Frontier’ Project for Private Universities (2001–2005 & 2006–2008): matching fund subsidy from the Ministry of Education, Culture, Sports, Science and Technology (MEXT).