Nematic Anchoring on Carbon Nanotubes

Isotropic to Nematic Phase Transition in Carbon Nanotube dispersed Liquid Crystal Composites

A high-resolution dielectric and calorimetric study of the isotropic (I) to nematic (N) phase transition of carbon nanotube (CNT) dispersed liquid crystal (LC) functional composites as a function of CNT concentration is reported. The evolution of the I-N phase transition, the temperature dependence of local nematic ordering formed by dispersed CNTs in the LC media and the transition enthalpy were coherently monitored. Anisotropic CNTs induce local deformation to the nematic director of LC and form lyotropic pseudo-nematic phase in the LC media. Results clearly indicate the dramatic impact of d…

Interaction of Spherical Colloidal Particles in Nematic Media with Degenerate Planar Anchoring

The interaction between two spherical colloidal particles with degenerate planar anchoring in a nematic media is studied by numerically minimizing the bulk Landau-de Gennes and surface energy using a finite element method. We find that the energy achieves its global minimum when the particles are in close contact and making an angle $θ= 28^\circ \pm 2$ with respect to the bulk nematic director, in agreement with the experiments. Although the quadrupolar structure of the director field is preserved in the majority of configurations, we show that for smaller orientation angles and at smaller int…

Self-organized composites of multiwalled carbon nanotubes and nematic liquid crystal 5CB: Optical singularities and percolation behavior in electrical conductivity

This work discusses optical singularities and electrical conductivity behavior in a thin electrooptical cell filled with composites including multi-walled carbon nanotubes (MWCNTs) and nematic liquid crystal (LC). The MWCNTs with high aspect ratio $L/d\approx 300\div1000$ and nematic LC 5CB (4-pentyl-4-0-cyanobiphenyl) were used. The composites were prepared by introduction of MWCNTs ($0.0001\div0.1$ % wt) into LC solvent with subsequent sonication. The increase of MWCNT concentration (between $0.005\div0.05$ % wt) resulted in self-organization of MWCNTs and formation of micron-sized aggregate…

向列型液晶中光激活胶体的群体感应

Quorum sensing of light-activated colloids in nematic liquid crystals

本研究提出一个实验平台，展示分散在向列型液晶中的光激活胶体可通过独特自驱动机制实现运动模式切换与群体感应，进而引发聚集相分离，为利用液晶和胶体特性创造类生命自适应材料提供了新途径。

Dielectric Hysteresis, Relaxation Dynamics, and Non-volatile Memory Effect in Carbon Nanotube Dispersed Liquid Crystal

The self-organizing properties of nematic liquid crystals (LC) can be used to template carbon nanotubes (CNTs) on a macroscopic dimension. The nematic director field, coupled to the dispersed CNT long-axis, enables controlled director reorientation using well-established methods of LC alignment techniques, such as patterned-electrode-surface, electric fields, and magnetic fields. Electric field induced director rotation of a nematic LC+CNT system is of potential interests due to its possible applications as a nano electromechanical system. The relaxation mechanism for a LC+CNT composite, on th…

Dispersions of multi-walled carbon nanotubes in liquid crystals: new challenges to molecular theories of anisotropic soft matter

Aggregation of carbon nanotubes dispersed in nematic liquid crystalline medium is discussed. A model is proposed, which assumes that the aggregates consist of a "skeleton" formed by stochastically arranged nanotubes and a "shell" ("coat") of incorporated and adjacent nematic molecules. The aggregates of this type can be considered as large quasi-macroscopic particles in the nematic matrix. The resulting composite system represents a new type of complex molecular liquids involving self-organization of particles in anisotropic medium. Many essential features and implications of the theoretical m…