Dielectric measurements have been made on three @entity70066 liquid crystal compounds exhibiting a @entity11280 ( @entity11280 ) to smectic C* (SmC*) transition, the @entity11280 phase being of the de Vries type. The electroclinic response of the molecules in the de Vries phase of these compounds exhibits a double-peak profile, and is thus different from the conventional chiral @entity11280 phase, a feature explained on the basis of an antiferroelectric (AF) block model (Krishna Prasad et al 2009 Phys. Rev. Lett. 102 147802). The differential interactions arising from the different molecular ends of these @entity19119 -based compounds, which are the basis for the @entity616 model, can also be expected to enhance the layer translational order. We present x-ray integrated intensity data that show a high (~0.9) translational order in the @entity11280 phase. Dielectric relaxation spectra bring out the fact that the magnitude of the soft mode relaxation parameters is dependent on the number of @entity19119 groups in the terminal part of the molecule. A range-shrinking analysis of the temperature-dependent dielectric relaxation strength has been carried out, using a power-law expression. The characteristic exponent shows a systematic growth with range shrinking and reaches limiting values comparable to that predicted for the 2D Ising universality class.

Critical behavior of three XXXX de Vries-type liquid crystals observed via the dielectric response.

@entity11280 :: ('6606', 'Gene') :: ['smectic A', 'SmA'] @entity19119 :: ('MESH:D012833', 'Chemical') :: ['siloxane'] @entity616 :: ('MESH:D006327', 'Disease') :: ['AF block'] @entity70066 :: ('CHEBI:48150', 'Chemical') :: ['organosiloxane']
@entity70066 :: (CHEBI:48150,Chemical) :: ['organosiloxane']
