Role of SiO2 optically active mediators to tailor optical and electro-optical properties of ferroelectric liquid crystalline nanocomposites

Characterization of optically thin cells and experimental liquid crystals

The current development of new liquid crystal devices often requires the use of thin cells and new experimental materials. Characterizing these devices and materials with optical methods can be challenging if (1) the total phase lag is small ("thin cells") or (2) the liquid crystal optical and dielectric properties are only partially known. We explore the limitations of these two challenges for efficient characterization and assessment of new, to the best of our knowledge, liquid crystal devices. We show that it is possible to extract a wealth of liquid crystal parameters even for cells with a phase lag of ΔΦ≈π, such as E7 liquid crystal in a 1.5 µm cell, using cross-polarized intensity measurements. The reliability of the optical method is also demonstrated for liquid crystals without precise values of dielectric or refractive index coefficients.

Conventional and unconventional ionic phenomena in tunable soft materials made of liquid crystals and nanoparticles

A great variety of tunable multifunctional materials can be produced by combining nanoparticles and liquid crystals. Typically, the tunability of such soft nanocomposites is achieved via external electric fields resulting in the field-induced reorientation of liquid crystals. This reorientation can be altered by ions normally present in liquid crystals in small quantities. In addition, nanomaterials dispersed in liquid crystals can also affect the behavior of ions. Therefore, an understanding of ionic phenomena in liquid crystals doped with nanoparticles is essential for future advances in liquid crystal-aided nanoscience and nanotechnology. This paper provides an overview of the ionic effects observed in liquid crystals doped with nanomaterials. An introduction to liquid crystals is followed by a brief overview of nanomaterials in liquid crystals. After giving a basic description of ions in liquid crystals and experimental methods to measure them, a wide range of ionic phenomena in liquid crystals doped with different types of nanomaterials is discussed. After that, both existing and emerging applications of tunable soft materials made of liquid crystals and nanodopants are presented with an emphasis on the role of ionic effects in such systems. Finally, the discussion of unsolved problems and future research directions completes the review.

Synthesis of high molar extinction coefficient push–pull tricyanofuran-based disperse dyes: Biological activity and dyeing performance

Novel push–pull tricyanofuran-based disperse dyes demonstrated high extinction coefficient, good antimicrobial performance and high colorfastness on polyester fibers.