Orientation of Ferroelectric Liquid Crystals by Self-Assembled Bilayer Molecular Assembly

2001 ◽  
Vol 709 ◽  
Author(s):  
Sukhmal C. Jain ◽  
Vivechana Dixit ◽  
Vinod K. Tanwar ◽  
S. M. Shivaprasad
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Uv Spectroscopy ◽  
Large Change ◽  
Molecular Assembly ◽  
Ferroelectric Liquid Crystal ◽  
Assembly Technique

ABSTRACTMolecular films of amino propyl triethoxy silane (APTES) attached with cinnamoyl moieties were deposited on indium tin oxide (ITO) coated glass and quartz substrates by self-assembly technique. The deposition of the monolayer films resulted in a large change in the wettability of the substrates. X-ray photoelectron spectroscopy (XPS) and UV-spectroscopy were used to study the structure and properties of the grown films. The molecular assembly was photodimerized by irradiating it with a linearly polarized UV-light. Thus created polymer-solid interface has been shown to produce good, stable planar orientation of ferroelectric liquid crystal mixtures. The electro-optical and switching properties of the ferroelectric liquid crystal cells have been investigated and found to be quite similar to those prepared in conventional manner.

scholarly journals Fabrication and in vitro evaluation of stable collagen/hyaluronic acid biomimetic multilayer on titanium coatings

2013 ◽  
Vol 10 (84) ◽  
pp. 20130070 ◽  
Author(s):  
Haiyong Ao ◽  
Youtao Xie ◽  
Honglue Tan ◽  
Shengbing Yang ◽  
Kai Li ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Human Mesenchymal Stem Cells ◽  
Biological Properties ◽  
Covalent Immobilization ◽  
Layer By Layer ◽  
Titanium Coating ◽  
Assembly Technique

Layer-by-layer (LBL) self-assembly technique has been proved to be a highly effective method to immobilize the main components of the extracellular matrix such as collagen and hyaluronic acid on titanium-based implants and form a polyelectrolyte multilayer (PEM) film by electrostatic interaction. However, the formed PEM film is unstable in the physiological environment and affects the long-time effectiveness of PEM film. In this study, a modified LBL technology has been developed to fabricate a stable collagen/hyaluronic acid (Col/HA) PEM film on titanium coating (TC) by introducing covalent immobilization. Scanning electron microscopy, diffuse reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the PEM film. Results of Sirius red staining demonstrated that the chemical stability of PEM film was greatly improved by covalent cross-linking. Cell culture assays further illustrated that the functions of human mesenchymal stem cells, such as attachment, spreading, proliferation and differentiation, were obviously enhanced by the covalently immobilized Col/HA PEM on TCs compared with the absorbed Col/HA PEM. The improved stability and biological properties of the Col/HA PEM covalently immobilized TC may be beneficial to the early osseointegration of the implants.

The development of self-assembled liquid crystal display alignment layers

2007 ◽  
Vol 365 (1855) ◽  
pp. 1553-1576 ◽  
Author(s):  
Johan Hoogboom ◽  
Johannes A.A.W Elemans ◽  
Alan E Rowan ◽  
Theo H.M Rasing ◽  
Roeland J.M Nolte
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Self Assembly ◽  
Liquid Crystal Display ◽  
Alignment Layer ◽  
Siloxane Oligomers ◽  
Mobile Telephones ◽  
Phthalocyanine Dyes ◽  
Alignment Layers ◽  
Potential Use

From simple pocket calculators to mobile telephones and liquid crystal display (LCD)-TV, over the past few decades, devices based on LCD technology have proliferated and can now be found in all conceivable aspects of everyday life. Although used in cutting-edge technology, it is surprising that a vital part in the construction of such displays, namely the alignment layer, relies essentially on a mechanical rubbing process, invented almost 100 years ago. In this paper efforts to develop alignment layers (also called command layers) by processes other than rubbing, namely self-assembly of molecular and macromolecular components will be discussed. Two topics will be presented: (i) tuneable command layers formed by stepwise assembling of siloxane oligomers and phthalocyanine dyes on indium tin oxide surfaces and (ii) command layers formed by self-assembly of porphyrin trimers. The potential use of these layers in sensor devices will also be mentioned.

scholarly journals Synthesis, Self-Assembly and Photoresponsive Behavior of Liquid Crystals Based on Azobenzene

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1560
Author(s):  
Yaming Wu ◽  
Yuhai Liu ◽  
Jianxiang Chen ◽  
Runmiao Yang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Self Assembly ◽  
Driving Force ◽  
1H Nmr Spectroscopy ◽  
Uv Light ◽  
Light Exposure ◽  
Scanning Calorimetry ◽  
Stimulus Response ◽  
Cis Isomer

A new amphiphilic surfactant (C4-Azo-C5-HDA) was formed by liquid crystals (LCs) based on azobenzene, whose structures were characterized by 1H-NMR spectroscopy. The reversible hydrogelation upon changes in temperature and light exposure was also studied. Under the irradiation of UV light, the trans-isomer of C4-Azo-C5-HDA rapidly photoisomerized to the cis-isomer, resulting in rapid disruption of the gel. The thermotropic liquid crystal behavior of the gelator was investigated via Differential Scanning Calorimetry (DSC) and Polarizing Optical Microscopy (POM). The biocompatibility experiment of multi-stimulus response of the liquid crystal provides a potential driving force for the development of biomaterials.

Preparation of Poly(diallydimethyl ammonium chloride) (PDDA)/Au Nanocomposite Film by In Situ Electrochemical Reduction and its Electrocatalytic Properties

2010 ◽  
Vol 123-125 ◽  
pp. 189-192
Author(s):  
Hong Wei Shi ◽  
Li Zhang ◽  
Cong Wang ◽  
Ke Ying Zhang
Keyword(s):  
Electrochemical Reduction ◽  
Ammonium Chloride ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Composite Films ◽  
Nanocomposite Films ◽  
Layer By Layer ◽  
X Ray ◽  
Assembly Technique

Nanocomposite films containing Au nanoparticles were fabricated by alternating adsorption of poly(diallydimethyl ammonium chloride) (PDDA) and HAuCl4 using layer-by-layer self-assembly technique and subsequent in situ electrochemical reduction of the AuCl4- ions. The composition and properties of the composite films were characterized by ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV).The UV-vis characteristic absorbances of PDDA and Au increase almost linearly with the number of bilayers, which suggests a progressive deposition with almost an equal amount of the PDDA and Au in each cycle. X-ray photoelectron spectroscopy further confirms the presence of the main components (such as PDDA and Au) of the nanocomposite films. Furthermore, the nanocomposite films also exhibit good electrocatalytic activity for the oxidation of ascorbic acid (AA), which may be used in electrochemical biosensors.

Photocatalytic Activity of Pd Doped Tin Dioxide Inverse Opal Films

2012 ◽  
Vol 534 ◽  
pp. 135-140 ◽  
Author(s):  
Yang Liu ◽  
Bo Li ◽  
You Wei Yao ◽  
Jing Jing Gao ◽  
Zhen Dong Liu ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Self Assembly ◽  
Tin Dioxide ◽  
Uv Light ◽  
Sol Gel ◽  
The Self ◽  
Inverse Opal ◽  
Polystyrene Microsphere ◽  
Assembly Technique

Inverse opal films (IOFs) of SnO2 doped with Pd were prepared by the self-assembly technique using polystyrene microsphere (PS sphere) as template in combination with a sol-gel method. The photocatalysis properties of SnO2 IOFs were estimated through measuring the rate of the degradation of methylene blue (MB). The result shows that SnO2 IOFs have good photocatalytic activity, the solution of MB was degradated over 60% in 4 hours when it was dipped in SnO2 IOFs and exposed in the UV light. The addition of Pd in SnO2 IOFs improved the photocatalytic activity of the films and the degradation of MB can exceed 80% with the same condition. This sort of SnO2 IOFs doped with Pd indicated a potential application in photocatalysis field.

Ultraviolet light response of electrical and dielectric properties in zinc phthalocyanine and fullerene dispersed liquid crystal composites

2015 ◽  
Vol 93 (10) ◽  
pp. 1207-1212 ◽  
Author(s):  
O. Köysal ◽  
M. Gökçen ◽  
M. Yıldırım
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Uv Light ◽  
Light Response ◽  
Research Area ◽  
Open Circuit ◽  
Zinc Phthalocyanine ◽  
Dielectric Anisotropy ◽  
Photovoltaic Properties ◽  
Power Intensity

Liquid crystal composites form an attractive research area in liquid crystal studies. Among these composites, nematic liquid crystal composited E63 is of particular interest. In the present study, E63 coded liquid crystal composites were dispersed with zinc phthalocyanine (Zn-Pc) and fullerene (C60), and three samples were prepared as E63, E63/Zn-Pc, and E63/Zn-Pc/C60 in indium tin oxide coated cells via capillary action. Later, current and capacitance measurements of the samples were carried out in darkness and under ultraviolet (UV) illumination (365 nm) of 100 mW/cm2 power intensity. It was found that both current and capacitance in the samples are affected by UV light and dispersal of Zn-Pc and C60. Particularly, dispersal of Zn-Pc led to occurrence of photovoltaic properties, which yielded open-circuit voltage of 0.37 V for the E63/Zn-Pc sample. Furthermore, dielectric constant and dielectric anisotropy values were extracted from capacitance values, and UV light was seen to increase the transition frequency of dielectric anisotropy slightly for all samples.

scholarly journals Akaganeite nanorices deposited muscovite mica surfaces as sunlight active green photocatalyst

2019 ◽  
Vol 6 (3) ◽  
pp. 182212 ◽  
Author(s):  
Anoja Senthilnathan ◽  
D. M. S. N. Dissanayake ◽  
G. T. D. Chandrakumara ◽  
M. M. M. G. P. G. Mantilaka ◽  
R. M. G. Rajapakse ◽  
...  
Keyword(s):  
Self Assembly ◽  
Uv Light ◽  
Average Particle ◽  
Efficient Treatment ◽  
X Ray ◽  
Force Microscopy ◽  
Highly Active ◽  
Muscovite Mica ◽  
Assembly Technique ◽  
Particle Length

Thin films of akaganeite [FeO(OH)] nanorices deposited muscovite mica (ANPM) surfaces are synthesized using the facile urea assisted controlled self-assembly technique. The synthesized materials are characterized using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The prepared nanorices on mica surfaces show average particle length and width of 200 and 50 nm, respectively. Synthesized material acts as an efficient photocatalyst under UV and sunlight conditions as demonstrated by the degradation of standard methylene blue (MB) solution. The MB degradation efficiencies of the catalyst under exposure to 180 min sunlight and UV are 89% and 87.5%, respectively, which shows that the catalyst is more highly active under sunlight than under UV light. Therefore, the synthesized material is a potential green photocatalyst in efficient treatment of industrial dye effluents under direct sunlight.

Effects of Ultraviolet-Light on Polyimide Films for Liquid Crystal Alignment

1998 ◽  
Vol 508 ◽  
Author(s):  
Shaoqin Gong ◽  
Jerzy Kanicki ◽  
Lan Ma ◽  
John Z. Z. Zhong
Keyword(s):  
Liquid Crystal ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Polyimide Film ◽  
Polyimide Films ◽  
Film Property ◽  
Uv Illumination ◽  
Angle Measurements ◽  
Property Changes ◽  
Pretilt Angle

AbstractUV-light effects on the polyimide films have been studied by characterizing the film property changes and by measuring the liquid crystal pretilt angle. Infrared, UV-visible and X-ray photoelectron spectroscopy measurements indicate that bond-breaking and oxidation occur during broadband UV-illumination of the film in the air. Free radicals are formed during UV-illumination as evidenced by the analysis of electron spin resonance spectra. Surface tension and polarity are increased after UV-illumination based on the contact angle measurements. While the pretilt angle on the rubbed polyimide film is decreased after nonpolarized UV-illumination, polarized UV-light generates a relatively small pretilt angle on a nonrubbed surface.

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