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Effect of the surrounding anisotropic liquid crystal medium on the surface plasmon resonance (SPR) exhibited by concentrated suspensions of gold nanospheres has been investigated experimentally and compared with the Mie scattering theory. The observed polarization-sensitive SPR and the red-shift in the SPR wavelength with increasing concentration of the gold nanospheres in the liquid crystal matrix have been explained using calculations based on the Maxwell Garnet effective medium theory. Agglomeration of the gold nanospheres that could also lead to such a red-shift has been ruled out using Atomic force microscopy study of thin nanoparticle-doped smectic films obtained on solid substrates. Our study demonstrates feasibility of obtaining tunable optical bulk metamaterials based on smectic liquid crystal - nanoparticle composites.

We report on two anomalous trends in the temperature dependences of the splay (K11) and bend (K33) elastic constants in the nematic (N) phase of mixtures of compounds with rodlike (R) and bent-core (BC) molecules: As the sample is cooled from the isotropic to N transition point, (i) K33 increases, attains a maximum value and then decreases, and (ii) close to the N to smectic A (SmA) transition point, K11 decreases sharply. At higher temperatures the bow axes of BC molecules are aligned along the director n, strongly favoring a bend distortion of n as the orientational order parameter is increased. Close to the N-SmA transition point the smecticlike short-range order builds up, and the arrow axes of BC molecules are aligned along n, facilitating a splay distortion of n. A simple model calculation brings out the anomalous trend in K33.

We report the discovery of an orientational transition of bent-core molecules in a background anisotropic medium, in this case a smectic liquid crystal made of rod-like molecules. The resulting director is apolar in nature, and the medium can be described as an orthogonal biaxial smectic. The detailed phase diagram of mixtures of the two types of compounds revealed the induction of two liquid crystalline phases that are specific to compounds with bent-core molecules. The chemical nature of the bounding surface had a marked influence on the observed textures.

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We demonstrate that the layer structure and elasticity stabilize dispersions of colloidal nanoparticles in smectic liquid crystals. We use surface plasmon resonance spectra of gold nanospheres to probe their spatial distributions in the bulk of smectic lamellae. The average interparticle distances between the well-separated nanoinclusions in thin ͑Ͻ100 nm͒ smectic films are probed by atomic force microscopy. We show that limited motion of nanoparticles across layers due to the one-dimensional quasi-long-range solid-like structure and their elasticity-mediated interactions preclude irreversible aggregation and enhance the stability of the ensuing nanoscale dispersions in thermotropic smectic liquid crystals.

In some binary mixtures of smectogenic and non-mesomorphic aliphatic compounds, the smectic A phase separates in the form of cylindrical structures. Our observations on some of these systems indicate that such structures are stabilised by a negative radial concentration gradient of the non-mesomorphic component. If the concentration of the non-mesomorphic component is allowed to increase in the isotropic phase, the cylindrical structures develop an undulation instability. It is argued that the concentration gradient leads to a spontaneous curvature in the smectic layers, which makes it necessary to include a term linear in curvature in the elastic energy density of such systems

We report calorimetric, Xray, electrooptic, electric-field and dielectric experiments conducted on the recently discovered undulated twist grain boundary-C* liquid crystal. The results are discussed on the basis of the structure of this new phase which is characterised by a two-dimensional modulation orthogonal to the TGB helical axis and a helical arrangement of the molecular director within the smectic blocks.