Location of Phase Boundaries of Lyotropic Liquid Crystal Employing Positron Lifetime Spectroscopy and Electrical Conductivity Measurement

2012 ◽  
Vol 733 ◽  
pp. 127-131
Author(s):  
Ramesh Yadav ◽  
K. Chandramani Singh ◽  
S.R. Choudhary ◽  
P.C. Jain
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Conductivity Measurement ◽  
Lyotropic Liquid Crystals ◽  
Lyotropic Liquid Crystal ◽  
Ammonium Bromide ◽  
Phase Boundaries ◽  
New Findings ◽  
Positron Lifetime Spectroscopy ◽  
Surfactant Systems

Different compositions of surfactant systems give rise to a rich variety of structures of aggregates. At higher concentrations of surfactant in water, the surfactant molecules aggregate to form lyotropic liquid crystals [1]. In the present work we have prepared two surfactant systems consisting of (i) 20% of cetyl-trimethyl-ammonium-bromide (CTAB) in water, and (ii) 30% of tetra-decyl-trimethyl-ammonium-bromide (TTAB) in water. Both the systems exhibit various lyotropic liquid crystal structures when an increasing amount of co-surfactant is added as third component [2, 3]. These liquid crystalline structures are very sensitive to the solution conditions such as co-surfactant concentration, temperature, ionic strength, counter ion polarizability etc. In this study, positron life time spectroscopy and conductivity measurement have been employed to locate various phases exhibited by the lyotropic liquid crystals. In addition to delineating various phase boundaries of the systems, positron annihilation technique has also yielded new findings.

Fabrication and Characterizes of TiO2 Nanomaterials Templated by Lyotropic Liquid Crystal

2011 ◽  
Vol 399-401 ◽  
pp. 532-537
Author(s):  
Li Hua Liu ◽  
Ying Bai ◽  
Fu Min Wang ◽  
Ning Liu
Keyword(s):  
Aqueous Solution ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nonionic Surfactant ◽  
Formation Mechanism ◽  
Lyotropic Liquid Crystals ◽  
Lyotropic Liquid Crystal ◽  
Micro Structure ◽  
Ft Ir ◽  
Rod Structures

TiO2 nanomaterials were synthesized in lyotropic liquid crystal formed by nonionic surfactant TritonX-100 and TiOSO4 aqueous solution with NH3•H2O as precipitator. The lyotropic liquid crystals were characterized by means of POM and Low-angle XRD. FT-IR, TGA, XRD, TEM were used to characterize the TiO2 samples. It was found that all the lytropic liquid crystal were in lamellar liquid crysal phase and after casting the micro-structure of the LLC phase, the TiO2 samples were self-assemble to form lamellar, sphere and rod structures. According to the characterization results, possible formation mechanism was proposed.

A pirfenidone loaded spray dressing based on lyotropic liquid crystals for deep partial thickness burn treatment: healing promotion and scar prophylaxis

2020 ◽  
Vol 8 (13) ◽  
pp. 2573-2588 ◽  
Author(s):  
Jintian Chen ◽  
Hui Wang ◽  
Liling Mei ◽  
Bei Wang ◽  
Ying Huang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Lyotropic Liquid Crystals ◽  
Lyotropic Liquid Crystal ◽  
Burn Treatment ◽  
Partial Thickness ◽  
Partial Thickness Burn

This study develops a HA combined lyotropic liquid crystal based spray dressing loaded with pirfenidone for wound healing and scar prophylaxis.

Synthesis and Application of the Three-Component Lyotropic Liquid Crystal

2015 ◽  
Vol 1095 ◽  
pp. 371-376
Author(s):  
Qiu Li Yang ◽  
Xin Ran Guan ◽  
Xiao Na Xie ◽  
Shao Wei Wei ◽  
Yi Wen Fang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ternary System ◽  
Optical Microscopy ◽  
Lyotropic Liquid Crystals ◽  
Lyotropic Liquid Crystal ◽  
Polarized Optical Microscopy ◽  
Texture Structure

This paper focused on synthesizing the surfactant lyotropic liquid crystals (LLCs) through mixing the coconut diethanol amide (6501), primary alcobol ethoxylate (AEO9) and water. The LLCs phases formed in the ternary system are thoroughly investigated by polarized optical microscopy (POM). The obtained LLCs were characterized by XRD and SEM in order to analysis the texture, structure and the transformation. In addition, the LLCs have been applied in the preparation of TiO2nanoparticles in our research. The obtained TiO2powder were characterized by XRD and SEM, more importantly, the results showed that the LLCs are effective in the process of synthesizing TiO2nanoparticles.

Initiator-dependent kinetics of lyotropic liquid crystal-templated thermal polymerization

2021 ◽  
Vol 12 (15) ◽  
pp. 2236-2252
Author(s):  
Younes Saadat ◽  
Kyungtae Kim ◽  
Reza Foudazi
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Thermal Polymerization ◽  
Lyotropic Liquid Crystals ◽  
Lyotropic Liquid Crystal ◽  
Kinetics Of

In this study, we show that how the locus of initiation can change kinetics and mechanical properties of polymerized lyotropic liquid crystals.

scholarly journals Aligning lyotropic liquid crystals with unconventional organic layers

2017 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Eva Otón ◽  
Morten Andreas Geday ◽  
Caterina Maria Tone ◽  
José Manuel Otón ◽  
Xabier Quintana
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Chem Phys ◽  
Water Soluble ◽  
Lyotropic Liquid Crystals ◽  
Sunset Yellow ◽  
Lab On Chip ◽  
Wide Range ◽  
Homeotropic Alignment ◽  
Alignment Layers

Lyotropic chromonic liquid crystals (LCLC) are a kind of LCs far less known and more difficult to control than conventional thermotropic nematics. Nevertheless, LCLCs are a preferred option -often the only one- for applications where hydrophilic materials must be employed. Being water-soluble, LCLC can be used in numerous biology related devices, for example in target detection in lab-on-chip devices. However, their properties and procedures to align them are still less explored, with only a very limited number of options available, especially for homeotropic alignment. In this work, novel organic alignment layers and alignment properties have been explored for selected LCLCs. Non-conventional organic alignment layers were tested and new suitable procedures and materials for both homogeneous and homeotropic alignments have been found. Full Text: PDF ReferencesS.L. Hefinstine, O.D. Lavrentovich, C.J. Woolverton, "Lyotropic liquid crystal as a real-time detector of microbial immune complexes", Lett. Appl. Microbiol. 43, 27 (2006). CrossRef M.A. Geday, M. Ca-o-García, J.M. Escolano, E. Otón, J.M. Otón, X. Quintana, Conference on Liquid Crystals CLC'16, Poland (2016).M.A. Geday, E. Otón, J.M. Escolano, J.M. Otón, X. Quintana, Patent WO 2015193525 (2015). DirectLink Yu.A. Nastishin et al., "Optical characterization of the nematic lyotropic chromonic liquid crystals: Light absorption, birefringence, and scalar order parameter", Phys. Rev. E, 72 (4) 41711 (2005). CrossRef A. Mcguire, et al., "Orthogonal Orientation of Chromonic Liquid Crystals by Rubbed Polyamide Films", Chem. Phys. Chem. 15 (7) (2014). CrossRef J. Jeong, et al., "Homeotropic Alignment of Lyotropic Chromonic Liquid Crystals Using Noncovalent Interactions", Langmuir 30(10) 2914 (2014). CrossRef J.Y. Kim, H.-Tae Jung, "Macroscopic alignment of chromonic liquid crystals using patterned substrates", Phys. Chem. Chem. Phys. 18, 10362 (2016). CrossRef E. Otón, J.M. Escolano, X. Quintana, J.M. Otón, M.A. Geday, "Aligning lyotropic liquid crystals with silicon oxides", Liq. Cryst. 42 (8) 1069 (2015). CrossRef H.S. Park, et al., "Condensation of Self-Assembled Lyotropic Chromonic Liquid Crystal Sunset Yellow in Aqueous Solutions Crowded with Polyethylene Glycol and Doped with Salt", Langmuir 27, 4164 (2011). CrossRef H.S. Park, et al., "Self-Assembly of Lyotropic Chromonic Liquid Crystal Sunset Yellow and Effects of Ionic Additives", J. Phys. Chem. B 112, 16307 (2008). CrossRef R Caputo et al., "POLICRYPS: a liquid crystal composed nano/microstructure with a wide range of optical and electro-optical applications", J. Opt. A: Pure Appl. Opt. 11, 024017 (2009). CrossRef

Liquid crystal/glass interface effects on the orientation of lyotropic liquid crystals in magnetic fields

1978 ◽  
Vol 56 (16) ◽  
pp. 2178-2183 ◽  
Author(s):  
Fred Y. Fujiwara ◽  
Leonard W. Reeves
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Cylindrical Tube ◽  
Lyotropic Liquid Crystals ◽  
Crystal Glass ◽  
Type I ◽  
Type Ii ◽  
Glass Interface ◽  
Interface Effects

Lyotropic mesophases of both positive (type I) and negative (type II) diamagnetic anisotropy have been prepared. The deuterium magnetic resonance signal from D2O in the sample bas been studied during the process of orientation in a magnetic field. A type II mesophase oriented by a magnetic field in a cylindrical tube perpendicular to the lines of force does not achieve a uniform distribution of directors in a plane perpendicular to the field. The re orientation of a type I mesophase after an initial displacement of the director at an angle to the field has been studied. Previous equations derived for thermotropic liquid crystals are applicable but the velocity of re-orientation was found to be an inverse function of the radius, for nmr tubes of less than 4 mm in diameter, indicating that liquid crystal/glass interface effects are important.

Novel Dichroic Polarizing Materials and Approaches to Large-Area Processing

1998 ◽  
Vol 508 ◽  
Author(s):  
Yuri. A. Bobrov ◽  
Sean M. Casey ◽  
Leonid. Y. Ignatov ◽  
Pavel I. Lazarev ◽  
Daniel Phillips ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystal Display ◽  
Substrate Surface ◽  
Continuous Production ◽  
Lyotropic Liquid Crystals ◽  
Large Area ◽  
Rigid Plastic ◽  
Coating Materials ◽  
Wide Range

AbstractWe have developed new polarizing coating materials and processes which enable the fabrication of polarizers for large-area liquid-crystal displays. The polarizing materials are novel discotic surfactants which self-assemble in aqueous solutions to provide a stable liquid-crystalline phase within a wide range of concentrations and temperatures. These lyotropic liquid crystals in an aqueous medium can be spread on a substrate surface by a variety of techniques including a knife-like doctor blade, a rolling cylinder, or a roll-to-roll method. Under the shearing force applied during deposition, the liquid crystals align on the substrate forming a dichroic polarizer. This alignment process allows continuous production of large-area polarizing films at low cost compared with the current technology that requires stretching of the films. Thin coatings can be applied to flexible plastic films, glass, or rigid plastic substrates. Direct coating of the polarizing material on glass eliminates several process steps in liquid-crystal display production since lamination of the polarizing film is no longer required. These new polarizing films have a high optical performance including a polarizing efficiency of above 98% and a dichroic ratio as high as 7.7.

scholarly journals Light-Controlled Lyotropic Liquid Crystallinity of Polyaspartates

2021 ◽  
Author(s):  
Max Hirschmann ◽  
Christina M. Thiele
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Morphological Changes ◽  
Thermal Relaxation ◽  
Lyotropic Liquid Crystals ◽  
Solution Viscosity ◽  
Layer By Layer ◽  
Nano Technology ◽  
Biological Responses ◽  
Photo Alignment

<p><b>In nature, proteins like rhodopsin act as transducer for photo-chemical reactions causing biological responses (e.g. enabling vision)</b><b>. The underlying concept – a photo-induced conformational change of the protein as amplifier of the photo-responsive moiety – can also be adopted by synthetical polymers or foldamers</b><b> </b><b>that have the propensity to form ordered secondary structures (e.g. polypeptides)</b><b>. An alternative approach to amplify photo-chemical responses is their incorporation into liquid crystals</b><b>. With only a few exceptions</b><b>, photo-insensitive liquid crystals are doped with dyes</b><b> </b><b>that favour disorder upon irradiation</b><b>. In theory, photo-responsive polypeptides</b><b>, capable of forming lyotropic liquid crystals</b><b>, could exploit both amplification approaches but, in practice, their photo-responsivity is hampered by the reduced mobility of polypeptides in concentrated solutions</b><b>. Here we show that the E/Z photo-isomerisation of an azobenzene containing polyaspartate initiates a helix-coil backbone transition, which reversibly alters the polypeptide solution from anisotropic to isotropic. In contrast to other photo-responsible polymers</b><b>14</b><b>, in which thermal relaxation to the more stable photo-isomer is quite fast, both photo-isomers are thermally stable and interconvertible by visible light in a single solvent. Local irradiation and magnetic fields lead to spatial resolution and unidirectional architectures of the liquid crystal, respectively. Our results demonstrate that photo-isomerisation on a molecular level is amplified in three stages via intra- and intermolecular interactions to yield a unidirectional, chiral liquid crystal. We believe, the morphological changes of the liquid crystal induced by light will facilitate a multitude of applications, like photo-alignment</b><b> </b><b>or the photo-control of solution viscosity</b><b> </b><b>and anisotropic </b><br></p> <p><b>diffusion</b><b>. When incorporated into layer-by-layer architectures the polymer could find application in biomedicine</b><b> </b><b>and the spatial and temporal resolution could be exploited in nano-technology</b><b>. </b></p>

scholarly journals Novel Trends in Lyotropic Liquid Crystals

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 604 ◽  
Author(s):  
Ingo Dierking ◽  
Antônio Martins Figueiredo Neto
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Soft Matter ◽  
Anisotropic Materials ◽  
Lyotropic Liquid Crystals ◽  
Electro Optic ◽  
Thermotropic Liquid Crystals ◽  
Active Liquid ◽  
Biological Liquid

We introduce and shortly summarize a variety of more recent aspects of lyotropic liquid crystals (LLCs), which have drawn the attention of the liquid crystal and soft matter community and have recently led to an increasing number of groups studying this fascinating class of materials, alongside their normal activities in thermotopic LCs. The diversity of topics ranges from amphiphilic to inorganic liquid crystals, clays and biological liquid crystals, such as viruses, cellulose or DNA, to strongly anisotropic materials such as nanotubes, nanowires or graphene oxide dispersed in isotropic solvents. We conclude our admittedly somewhat subjective overview with materials exhibiting some fascinating properties, such as chromonics, ferroelectric lyotropics and active liquid crystals and living lyotropics, before we point out some possible and emerging applications of a class of materials that has long been standing in the shadow of the well-known applications of thermotropic liquid crystals, namely displays and electro-optic devices.

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