High-resolution dielectric anisotropy investigation of carbon nanotube-smectic-A liquid crystal dispersions: An upper limit of the latent heat and the pretransitional anomaly at the nematic-smectic-A transition.

Within the entire mesomorphic range, high-precision dielectric anisotropy data with the high-temperature resolution is presented for a highly polar smectic-A liquid crystal 8CB (octylcyanobiphenyl) as well as 8CB nanocomposites doped with both pristine multi-walled carbon nanotubes (p-MWCNTs) and carboxyl group (-COOH) functionalized MWCNTs (f-MWCNTs). The temperature variation of the nematic order parameter across both the nematic-isotropic (N-I) and the nematic-smectic-A (N-Sm-A) phase transitions of the neat 8CB and 8CB+MWCNT nanocomposites has then been derived from the dielectric anisotropy data within the framework of the Maier-Meier theory. With the inclusion of MWCNTs, both the N-I and the N-Sm-A transition temperatures have been noted to shift to lower temperatures as compared to the 8CB host.

Test of Halperin-Lubensky-Ma crossover function at the N-Sm-A transition in liquid crystal binary mixtures via high-resolution birefringence measurements.

We report optical birefringence data for a series of mixtures of the liquid crystals octylcyanobiphenyl (8CB) and decylcyanobiphenyl (10CB). Nematic order parameter S data in the nematic and smectic A phases have been derived from phase angle changes obtained in temperature scans with a rotating analyzer method. These S values have been used to arrive at values for possible entropy discontinuities at the smectic A to nematic phase transition temperature T_{NA}.

Critical behavior of a nonpolar smectogen from high-resolution birefringence measurements.

We report high-sensitivity and high-temperature resolution experimental data for the temperature dependence of the optical birefringence of a nonpolar monolayer smectogen 4-butyloxyphenyl-4'-decyloxybenzoate (10[over ¯].O.4[over ¯]) liquid crystal by using a rotating-analyzer technique.

Scaling of thermal hysteresis at nematic-smectic-A phase transition in a binary mixture.

The photon transmission method was applied to study the scaling of thermal hysteresis at the nematic-smectic-A transition in a binary mixture of 4-ethoxy-4(')-(6-vinyloxyhexyloxyl) azobenzene monomer, smectogen, and 4-hexoxy-3(')-methly-4(')-(6-acryloyloxyhexyloxy) azobenzene. The thermal hysteresis loops were obtained under linearly varying temperature. It has been found that the area A of the hysteresis loops scales with the temperature scanning rate R as A=A(0)+bR(n) with the exponent n equal to 0.