The phase transition behaviour of the chiral liquid crystal CE6 doped with spherical surface-functionalised CdSe nanoparticles has been examined by means of high-resolution adiabatic scanning calorimetry and polarising microscopy. The addition of nanoparticles results in an essentially stabilised blue phase III. The phase diagram is displayed upon heating and cooling and the enthalpy changes involved in the conversion between the blue phases are determined. The dispersion of functionalised nanoparticles is prominent for the stabilisation of blue phase III, which is potentially useful for applications, especially if applied on liquid crystals that exhibit blue phases close to room temperature.

A detailed x-ray scattering and high-resolution ac calorimetric study has been carried out near the smectic-$A$ to chiral smectic-$C$ phase transition of liquid-crystal compounds 4-(2-methyl butyl) phenyl 4-$n$-octylbiphenyl-4-carboxylate (CE8) and $p$-($n$-decyloxy) benzylidene-$p$-amino-(2-methylbutyl) cinnamate (DOBAMBC) confined in hydrophilic and hydrophobic aerosil nanoparticle networks. The character of the transition, which is mean field near a tricritical point in bulk, is changed dramatically with an increase of aerosil-induced disorder. X-ray measurements revealed pretransitional behavior and compression of the smectic layers, phenomena that are strongly pronounced in high aerosil concentrations. A theoretical model that takes into account the interplay of relevant mechanisms is proposed to explain the observed phenomena. The effect of chirality on the interaction of liquid crystals with aerosils is discussed.

Spherical CdSe nanoparticles, surface-treated with oleylamine and tri-octylphosphine, dispersed in ferroelectric liquid crystals, can efficiently target disclination lines, substantially altering the macroscopic properties of the host compound. Here we present an ac calorimetry and x-ray diffraction study demonstrating that for a large range of nanoparticle concentrations the smectic-$A$ layer thickness increases monotonically. This provides evidence for enhanced accumulation of nanoparticles at the smectic layers. Our results for the Smectic-$A$ (Sm$A$) to chiral smectic-$C$ (Sm${C}^{*}$) phase transition of the liquid crystal S-(+)4-(2${}^{$'${}}$-methylbutyl)phenyl-4${}^{$'${}}$-n-octylbiphenyl-4-carboxylate (CE8) reveal that the character of the transition is profoundly changed as a function of the nanoparticle concentration. Large transition temperature shifts are recorded. Moreover, the heat-capacity peaks exhibit a crossover trend to a step-like anomaly. This behavior may be linked to the weakening of the Sm$A$ and Sm${C}^{*}$ order parameter coupling responsible for the observed near-tricritical, mean-field character of the transition in bulk CE8. At lower temperatures, the presence of nanoparticles disrupts the phase sequence involving the tilted hexatic phases most likely by obstructing the establishment of long-range bond-orientational order.

Hydrophilic and hydrophobic aerosil particles immersed in S-(+)-[4-(2-methylbutyl) phenyl 4-$n$-octylbiphenyl-4-carboxylate] or [$p$-($n$-decyloxy) benzylidene-$p$-amino-(2-methylbutyl) cinnamate] compound have been studied by employing x-ray diffraction. The aerosil-induced relative layer compression $\Delta d$ has been measured in the smectic $A$ phase as a function of aerosil concentration $x$. $\Delta d\left(x\right)$ is shown to sensitively monitor the intermediate-rigid transition of the adaptive aerosil network. The dominant mechanism leading to the $\Delta d\left(x\right)$ profiles is the global establishment of the aerosil-induced molecular tilt in the smectic $A$ phase.