scholarly journals LIQUID CRYSTAL MATERIALS ORIENTATION USING NEW APPROACH

2019 ◽  
Vol 7 ◽  
pp. 933-937
Author(s):  
Natalia Kamanina

It is well known that the liquid crystal (LC) mesophase is actively used in display technique and biomedicine devices. Unfortunately, the switching time of the devices based on the LCs is not fast enough; thus, it is very important to find novel perspective ways to obtain the good switching time of the LC dipoles used in these devices. Initial orientation of the LC molecules influences the dynamic parameters, for example, the switch-on and switch-off characteristics and the diffraction efficiency of the final devices. Among the different methods and approaches to find the optimized orientation of the inertial LC molecules a nanotechnology approach has shown the best results. This approach allows increasing the transparency, to decrease the resistivity and the number of the functional layers in the sandwich LC structures. Thus, it results in a decrease in the applied bias voltage. The effect is based on the fact that the ITO coating can be considered as the conducting layer and as the orienting (alignment) layer simultaneously. In the current paper, we continue our steps in the direction to find the best way of the LC molecules orientation. It is proposed to consider the LC media sensitization process as the method to change the surface relief when this relief is prepared from the polymeric orienting materials doped with the carbon nano-objects. Based on the solid fullerene-doped polyimide thin films and other organics it can be shown that the content of the fullerenes influences the wetting angle significantly. The fullerene concentration is correlated with the different surface relief view applied in the aligning of the LC molecules. The switching of the LC can be improved; furthermore the novel relief depended on the fullerene content can be used for the optical limiting of the laser irradiation.

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2587
Author(s):  
Fu-Lun Chen ◽  
Hui-Tzung Luh ◽  
Yu-Cheng Hsiao

We reveal a novel design for dye-doped liquid crystal (DDLC) microfluidic biosensing chips in the polydimethylsiloxane material. With this design chip, the orientation of DDLCs was affected by the interface between the walls of the channels and DDLCs. When the inside of a channel was coated with an N,N-dimethyl-n-octadecyl-3-aminopropyltrimethoxysilyl chloride (DMOAP) alignment layer, the DDLCs oriented homeotropically in a homeotropic (H) state under cross-polarized microscopy. After immobilization of antigens with antibodies on the alignment layer-coated microchannel walls, the optical intensity of the DDLC change from the dark H state to the bright planar (P) state. Using pressure-driven flow, the binding of antigens/antibodies to the DDLCs could be detected in an experimental sequential order. The microfluidic DDLCs were tested by detecting bovine serum albumin (BSA) and its immune-responses of antigens/antibodies. We proved that this immunoassay chip was able to detect BSA antigens/antibodies pairs with the detection limit about 0.5 µg/mL. The novel DDLC chip was shown to be a simple, multi-detection device, and label-free microfluidic chips are presented.


RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41693-41702
Author(s):  
Yunho Shin ◽  
Jinghua Jiang ◽  
Guangkui Qin ◽  
Qian Wang ◽  
Ziyuan Zhou ◽  
...  

A polymer stabilized LC based light waveguide display is reported. Performance is improved by patterned photo-polymerization or electrode. It has high brightness, ultrafast switching time, high contrast ratio, and high transmittance for transparent and augmented displays.


2008 ◽  
Vol 47 (6) ◽  
pp. 4751-4754 ◽  
Author(s):  
Sudarshan Kundu ◽  
Mitsuhiro Akimoto ◽  
Itaru Hirayama ◽  
Masaru Inoue ◽  
Shunsuke Kobayashi ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1098
Author(s):  
Agata Blacha-Grzechnik

For many years, the research on conjugated polymers (CPs) has been mainly focused on their application in organic electronics. Recent works, however, show that due to the unique optical and photophysical properties of CPs, such as high absorption in UV–Vis or even near-infrared (NIR) region and efficient intra-/intermolecular energy transfer, which can be relatively easily optimized, CPs can be considered as an effective light-activated source of versatile and highly reactive singlet oxygen for medical or catalytic use. The aim of this short review is to present the novel possibilities that lie dormant in those exceptional polymers with the extended system of π-conjugated bonds.


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 268
Author(s):  
Jeong-Hoon Ko ◽  
Jun-Chan Choi ◽  
Dong-Jin Lee ◽  
Jae-Won Lee ◽  
Hak-Rin Kim

In liquid crystal (LC) displays, deriving an optimum resistance level of an LC alignment polyimide (PI) layer is important because of the trade-off between the voltage holding and surface-discharging properties. In particular, to apply a power-saving low-frequency operation scheme to fringe-field switching (FFS) LC modes with negative dielectric LC (n-LC), delicate material engineering is required to avoid surface-charge-dependent image flickering and sticking problems, which severely degrade with lowering operation frequency. Therefore, this paper proposes a photocontrolled variable-resistivity PI layer in order to systematically investigate the voltage holding and discharging properties of the FFS n-LC modes, according to the PI resistivity (ρ) levels. By doping fullerene into the high-ρ PI as the photoexcited charge-generating nanoparticles, the ρ levels of the PI were continuously controllable with a wide tunable range (0.95 × 1015 Ω∙cm to 5.36 × 1013 Ω∙cm) through Ar laser irradiation under the same LC and LC alignment conditions. The frequency-dependent voltage holding and discharge behaviors were analyzed with photocontrolled ρ variation. Thus, the proposed experimental scheme is a feasible approach in PI engineering for a power-saving low-frequency FFS n-LC mode without the image flickering and image sticking issues.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 547
Author(s):  
DaEun Yang ◽  
Kyutae Seo ◽  
Hyo Kang

We synthesized a series of renewable and plant-based isoeugenol-substituted polystyrenes (PIEU#, # = 100, 80, 60, 40, and 20, where # is the molar percent content of isoeugenol moiety), using polymer modification reactions to study their liquid crystal (LC) alignment behavior. In general, the LC cells fabricated using polymer film with a higher molar content of isoeugenol side groups showed vertical LC alignment behavior. This alignment behavior was well related to the surface energy value of the polymer layer. For example, vertical alignments were observed when the polar surface energy value of the polymer was smaller than approximately 3.59 mJ/m2, generated by the nonpolar isoeugenol moiety with long and bulky carbon groups. Good alignment stability at 100 °C and under ultraviolet (UV) irradiation of 15 J/cm2 was observed for the LC cells fabricated using PIEU100 as a LC alignment layer. Therefore, renewable isoeugenol-based materials can be used to produce an eco-friendly vertical LC alignment system.


2007 ◽  
Vol 20 (S1) ◽  
pp. 198-201 ◽  
Author(s):  
Pavani Kotakonda ◽  
Izabela Naydenova ◽  
Robert Howard ◽  
Suzanne Martin ◽  
Vincent Toal

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