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It is well known that doping nanoparticles (NPs) in liquid crystals (LCs) can easily change the physical and electro-optical properties of LC mixture. In this paper, we demonstrate homogeneous, aligned nematic LC (N-LC) system dispersed in iron oxide (Fe2O3) NPs. The prepared Fe2O3 NPs have an average particle size of 50 nm. By changing the doping concentration of Fe2O3 NPs, we observed the characteristics of LC systems. Electrooptical (EO) characteristics included faster rising and falling times (2.14 ms and 10.24 ms, respectively) and lower driving voltage (1.45 V) compared with a pure N-LC cell. We demonstrated these results via the relationship between dielectric con- stant and LC device properties. The results were verified by software simulation based on general physical properties. Moreover, we observed that LC system with Fe2O3 NPs could be accomplished without capacitance hysteresis by capturing charged impurities. Superior performance of LC cell with Fe2O3 NPs indicates that the proposed LC system have strong potential for use in the production of advanced LC displays.

Uniaxial alignment of liquid crystals (LCs) is prerequisite for a vast number of LC applications. To accomplish stable and uniform LC orientation, an alignment process to orient the LCs is required. Herein, we demonstrate a simple strategy for fabricating novel LC alignment layers that ensures well aligned LC, superior switching without any capacitance hysteresis, low transmittance loss, and high thermal stability with sufficient anchoring action. Thin films of reactive mesogens (RMs) were transferred onto conventional homeotropic polyimides from a UV-cured RM stamp via contact printing. LC displays using defect free RM/PI polymeric stacks exhibited superior electro-optic (EO) properties to those containing rubbed PI layers. This approach allows for the fabrication of various-mode LC displays such as twisted nematic (TN), in-plane switching (IPS), and optically compensated bend (OCB) mode LCDs by changing the combinations of RMs, base PIs and LCs.

We examined the properties of nematic liquid crystal (N-LC) systems with dispersed nickel oxide nanoparticles (NPs). Uniform LC alignments with regular pretilt angles were achieved on rubbed polymer surface regardless of NiO nanoparticles concentration. We confirmed the electro-optical characteristics of twisted nematic (TN) cells containing NiO nanoparticles on rubbed polymer surface, which exhibited lower threshold voltages and faster response times with less capacitance hysteresis than pure LC cells. It is clear that the response time of TN cells on rubbed polymer surfaces decreases with increasing the NiO nanoparticles concentration. These results demonstrate the relationship between NP doping concentration and trapping of impurity ions, and were confirmed by a software simulation of electric flux and field density. NiO nanoparticles in the LC cells focused the electric field flux and strengthened the electric field. Further, NiO nanoparticles in LC medium trapped charged ionic impurities and suppressed the screen effect, leading to a stronger electric field and the van der Waals interactions between LC molecules and the alignment layers.