Nanoparticles in Liquid Crystals and Liquid Crystalline Nanoparticles

Abstract

Combinations of liquid crystals and materials with unique features as well as properties at the nanoscale are reviewed. Particular attention is paid to recent developments, i.e., since 2007, in areas ranging from liquid crystal-nanoparticle dispersions to nanomaterials forming liquid crystalline phases after surface modification with mesogenic or promesogenic moieties. Experimental and synthetic approaches are summarized, design strategies compared, and potential as well as existing applications discussed. Finally, a critical outlook into the future of this fascinating field of liquid crystal research is provided.

Nano-Objects and Ions in Liquid Crystals: Ion Trapping Effect and Related Phenomena

“…Since the well-developed surface (in other words, the high surface to volume ratio) and strong enough attractive interactions between the surface of the purifying agents and the ion are the two major factors affecting the trapping efficiency, nanoparticles known for their extremely high surface to volume ratio are promising candidates for the development of the ion capturing agents. Recent progress in the design of nanomaterials and their successful incorporation in liquid crystals [105][106][107][108][109][110][111][112][113][114][115][116][117] provides the foundation for considering nano-objects embedded in liquid crystals as ion capturing agents. We will discuss the property of nanoparticles to trap ions in the next section of this manuscript.…”

“…The intriguing properties of nanoparticles in liquid crystals are being actively studied in many laboratories around the globe, and we refer readers to review manuscripts available on this subject for more details [105][106][107][108][109][110][111][112][113][114][115][116][117]. In this section, we will analyze the existing literature from the perspective of the ion capturing phenomenon.…”

“…Metal nanoparticles are widely used as dopants to modify/change/alter the physical properties of liquid crystals [106][107][108]110,113,115]. Table 3 provides a short summary of their effects on the electrical properties of liquid crystals [154][155][156][157][158][159][160][161][162][163][164][165][166][167][168][169][170][171][172].…”

Discotic liquid crystal-nanoparticle hybrid systems

“…Both SWNTs and MWNTs have been dispersed in many LCs, and their effects on the electro-optical properties of LCs have been extensively studied by several researchers. 4,6,74,75 DLCs and CNTs have many similarities, for example, both are anisotropic materials; both possess self-assembling properties and often form hexagonal aggregates; and both exhibit 1-D conducting properties and have thus been considered as 'molecular wires.' These similarities prompted us to prepare DLC-CNT hybrid systems.…”

“…[6][7][8] Efforts have been made to alter the physical properties of NPs and LCs either by attaching liquid crystalline molecules covalently to NPs or by adding a low concentration of NPs to a liquid crystalline matrix. A variety of zero-dimensional (0-D), one-dimensional (1-D) and two-dimensional (2-D) NPs have been explored to prepare LC-NP hybrid systems.…”