The synthesis and properties of a few dozen highly evolved analogues of (S)-MHPOBC are reported. The liquid crystal phases, and phase transition temperatures and enthalpies, as evidenced by polarized optical microscopy and differential scanning calorimetry, respectively, are given. The helical pitch in pure compounds and some mixtures is estimated using the selective reflection method. All of the compounds show antiferroelectric phases, and some key structure–property relationships for the new materials are reported. Specifically, it is found that the length of the oligomethylene segment of a novel partially fluorinated alkoxy ether tail incorporated into the structures strongly influences the stability of the antiferroelectric phase and the observed phase sequences, as well as the values of the helical pitch and its temperature dependence. The formulation of a family of broad temperature range eutectic mixtures possessing the highly desirable orthoconic antiferroelectric phases with long helical pitch is described.

The design and characterisation of a reconfigurable multi-level spiral phase plate is shown. The device is based on a pie-shape liquid-crystal structure with 24 slices driven by custom electronics that allow independent excitation control of each electrode. The electrooptical cell was manufactured using maskless laser ablation lithography and has shown an unprecedented high fill factor. The topological charge can be dynamically changed between 1, 2, 3, 4, 6, 8 and 12. The device has been calibrated and characterised at 632.8 nm but can be employed at any wavelength in the visible and near infrared spectrum, just modifying the driving parameters of the electrodes. The experimental results have been compared to predictions derived from simulations. An excellent correspondence between theoretical and experimental result has been found in all cases.

Molecular structures and their relation to the mesogenic behavior as well as physical parameters of orthoconic antiferroelectric smectic phases formed by partially fluorinated esters are reviewed. New multicomponent mixtures with long pitch and their electrooptical performance are demonstrated.

Electro-optical properties and dielectric relaxation phenomenon have been investigated for antiferroelectric liquid-crystal mixture W-132A exhibiting $\mathrm{Sm}{\mathrm{A}}^{*}$ , $\mathrm{Sm}{\mathrm{C}}^{*}$ , and wide temperature range $(\sim 0–48°\mathrm{C})$ induced $\mathrm{Sm}{\mathrm{C}}_A^{*}$ phases. Spontaneous polarization, tilt angle, response time, viscosity, relaxation frequency, dielectric strength, and distribution parameter have been determined as a function of temperature. Switching process has been studied in the antiferroelectric $\mathrm{Sm}{\mathrm{C}}_A^{*}$ phase with the help of transmission intensity-voltage characteristics. Impedance spectroscopy of the material under the planar anchoring conditioning of the sample has been carried out in the frequency range of $1\mathrm{Hz}–10\mathrm{MHz}$ . Usual soft-mode dielectric relaxation in the $\mathrm{Sm}{\mathrm{A}}^{*}$ phase and Goldstone mode in the $\mathrm{Sm}{\mathrm{C}}^{*}$ phase have been observed. A tendency of the soft mode to penetrate into the $\mathrm{Sm}{\mathrm{C}}^{*}$ phase and that of the Goldstone mode into the $\mathrm{Sm}{\mathrm{C}}_A^{*}$ phase have been observed. The dielectric spectrum of the $\mathrm{Sm}{\mathrm{C}}_A^{*}$ phase exhibits two absorption peaks, namely, $P_L$ and $P_H$ modes which are separated by about two decades of frequency. $P_L$ is related to in-phase azimuthal angle fluctuation of the molecules in antitilt pairs, whereas $P_H$ is due to the antiphase fluctuation of the molecules in antitilt pairs.

The inclusion of nanoparticles modifies a number of fundamental properties of many materials. Doping of nanoparticles in self-organized materials such as liquid crystals may be of interest for the reciprocal interaction between the matrix and the nanoparticles. Elongated nanoparticles and nanotubes can be aligned and reoriented by the liquid crystal, inducing noticeable changes in their optical and electrical properties. In this work, cells of liquid crystal doped with high aspect ratio multi-walled carbon nanotubes have been prepared, and their characteristic impedance has been studied at different frequencies and excitation voltages. The results demonstrate alterations in the anisotropic conductivity of the samples with the applied electric field, which can be followed by monitoring the impedance evolution with the excitation voltage. Results are consistent with a possible electric contact between the coated substrates of the LC cell caused by the reorientation of the nanotubes. The reversibility of the doped system upon removal of the electric field is quite low.