scholarly journals Steady-state rheology and structure of soft hybrid mixtures of liquid crystals and magnetic nanoparticles

Soft Matter ◽  
2020 ◽  
Vol 16 (10) ◽  
pp. 2516-2527
Author(s):  
Gaurav P. Shrivastav ◽  
Nima H. Siboni ◽  
Sabine H. L. Klapp
Keyword(s):  
Liquid Crystal ◽  
Steady State ◽  
Liquid Crystals ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Dipolar Coupling ◽  
Hybrid Mixtures

The rhology of liquid crystal–magnetic nanoparticle mixtures is strongly dependent on the strength of the dipolar coupling among the magnetic nanoparticles.

Doping of nematic cyanobiphenyl liquid crystals with mesogen-hybridized magnetic nanoparticles

2017 ◽  
Vol 19 (19) ◽  
pp. 12127-12135 ◽  
Author(s):  
Ingo Appel ◽  
Hajnalka Nádasi ◽  
Christian Reitz ◽  
Nerea Sebastián ◽  
Horst Hahn ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Surface Engineering

Surface engineering of magnetic nanoparticles with (pro-)mesogenic ligands leads to colloidally stable magnetic nanoparticle–liquid crystal hybrids with interesting magneto-optical properties.

Evaluation of a Hue Capturing Based Transient Liquid Crystal Method for High-Resolution Mapping of Convective Heat Transfer on Curved Surfaces

1993 ◽  
Vol 115 (2) ◽  
pp. 311-318 ◽  
Author(s):  
C. Camci ◽  
K. Kim ◽  
S. A. Hippensteele ◽  
P. E. Poinsatte
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Steady State ◽  
Liquid Crystals ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Bottom Surface ◽  
Curved Surfaces ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Accurate determination of convective heat transfer coefficients on complex curved surfaces is essential in the aerothermal design and analysis of propulsion system components. The heat transfer surfaces are geometrically very complex in most of the propulsion applications. This study focuses on the evaluation of a hue capturing technique for the heat transfer interpretation of liquid crystal images from a complex curved heat transfer surface. Impulsively starting heat transfer experiments in a square to rectangular transition duct are reported. The present technique is different from existing steady-state hue capturing studies. A real-time hue conversion process on a complex curved surface is adopted for a transient heat transfer technique with high spatial resolution. The study also focuses on the use of encapsulated liquid crystals with narrow color band in contrast to previous steady-state hue based techniques using wide band liquid crystals. Using a narrow band crystal improves the accuracy of the heat transfer technique. Estimated uncertainty for the heat transfer coefficient from the technique is about 5.9 percent. A complete heat transfer map of the bottom surface was possible using only seven liquid crystal image frames out of the 97 available frames during the transient experiment. Significant variations of heat transfer coefficients are quantitatively visualized on the curved surfaces of the transition duct.

scholarly journals Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1023
Author(s):  
Peter Bury ◽  
Marek Veveričík ◽  
František Černobila ◽  
Peter Kopčanský ◽  
Milan Timko ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Magnetic Nanoparticles ◽  
Electric Fields ◽  
Acoustic Waves ◽  
Structural Changes ◽  
Surface Acoustic Waves ◽  
Theoretical Background ◽  
Isotropic Phase ◽  
Structure Of Nanoparticles

The surface acoustic waves (SAWs) were used to study the effect of magnetic nanoparticles on nematic liquid crystal (NLC) behavior in weak magnetic and electric fields. The measurement of the attenuation of SAW propagating along the interface between piezoelectric substrate and liquid crystal is showed as an effective tool to study processes of structural changes. The magnetic nanoparticles Fe3O4 of nanorod shape and different low volume concentration were added to the NLC (4-(trans-4′-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT)) during its isotropic phase. In contrast to undoped liquid crystals the distinctive different SAW attenuation responses induced by both magnetic and also electric fields in studied NLC samples were observed suggesting both structural changes and the orientational coupling between both magnetic and electric moments of nanoparticles and the director of the NLC molecules. Experimental measurements including the investigation under linearly increasing and/or jumped magnetic and electrical fields, respectively, as well as the investigation of temperature and time influences on structural changes were done. The investigation of the SAW anisotropy gives supplemental information about the internal structure of nanoparticles in investigated NLCs. In addition, some magneto-optical investigations were performed to support SAW results and study their stability and switching time. The analysis of observed SAW attenuation characteristics confirmed the role of concentration of magnetic nanoparticles on the resultant behavior of investigated NLC compounds. Obtained results are discussed within the context of previous ones. The theoretical background of the presented SAW investigation is introduced, too.

Structuralization of magnetic nanoparticles in 5CB liquid crystals

Soft Matter ◽  
2017 ◽  
Vol 13 (43) ◽  
pp. 7890-7896 ◽  
Author(s):  
Veronika Gdovinová ◽  
Martin A. Schroer ◽  
Natália Tomašovičová ◽  
Ingo Appel ◽  
Silke Behrens ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Magnetic Nanoparticles ◽  
Composite Systems

This work is devoted to the study of highly stable composite systems of the liquid crystal 4-n-pentyl-4′-cyanobiphenyl (5CB) doped with CoFe2O4 magnetic nanoparticles.

New structure induced by elastic anisotropy in cylindrical nematic liquid crystal

2017 ◽  
Vol 13 (2) ◽  
pp. 4705-4717
Author(s):  
Zhang Qian ◽  
Zhou Xuan ◽  
Zhang Zhidong
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals ◽  
Gennes Theory

Basing on Landau–de Gennes theory, this study investigated the chiral configurations of nematic liquid crystals confined to cylindrical capillaries with homeotropic anchoring on the cylinder walls. When the elastic anisotropy (L2/L1) is large enough, a new structure results from the convergence of two opposite escape directions of the heterochiral twist and escape radial (TER) configurations. The new defect presents when L2/L1≥7 and disappears when L2/L1<7. The new structure possesses a heterochiral hyperbolic defect at the center and two homochiral radial defects on both sides. The two radial defects show different chiralities.

scholarly journals Liquid Crystal Devices for Beam Steering Applications

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 247
Author(s):  
Rowan Morris ◽  
Cliff Jones ◽  
Mamatha Nagaraj
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Adaptive Optics ◽  
Beam Steering ◽  
Optical Components ◽  
Advantages And Disadvantages ◽  
Liquid Crystal Devices

Liquid crystals are valuable materials for applications in beam steering devices. In this paper, an overview of the use of liquid crystals in the field of adaptive optics specifically for beam steering and lensing devices is presented. The paper introduces the properties of liquid crystals that have made them useful in this field followed by a more detailed discussion of specific liquid crystal devices that act as switchable optical components of refractive and diffractive types. The relative advantages and disadvantages of the different devices and techniques are summarised.

scholarly journals Understanding intracellular nanoparticle trafficking fates through spatiotemporally resolved magnetic nanoparticle recovery

2021 ◽  
Author(s):  
Emily Sheridan ◽  
Silvia Vercellino ◽  
Lorenzo Cursi ◽  
Laurent Adumeau ◽  
James A. Behan ◽  
...  
Keyword(s):  
Decision Making ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Magnetic Extraction

We describe how magnetic nanoparticles can be used to study intracellular nanoparticle trafficking, and how magnetic extraction may be integrated with downstream analyses to investigate nanoscale decision-making events.

scholarly journals Therapeutic Potential of Magnetic Nanoparticle-Based Human Adipose-Derived Stem Cells in a Mouse Model of Parkinson’s Disease

2021 ◽  
Vol 22 (2) ◽  
pp. 654
Author(s):  
Ka Young Kim ◽  
Keun-A Chang
Keyword(s):  
Parkinson’S Disease ◽  
Stem Cells ◽  
Parkinson's Disease ◽  
Magnetic Nanoparticles ◽  
Substantia Nigra ◽  
Mouse Model ◽  
Magnetic Nanoparticle ◽  
Imaging System ◽  
Therapeutic Potential ◽  
Adipose Derived Stem Cells

Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra. Several treatments for PD have focused on the management of physical symptoms using dopaminergic agents. However, these treatments induce various adverse effects, including hallucinations and cognitive impairment, owing to non-targeted brain delivery, while alleviating motor symptoms. Furthermore, these therapies are not considered ultimate cures owing to limited brain self-repair and regeneration abilities. In the present study, we aimed to investigate the therapeutic potential of human adipose-derived stem cells (hASCs) using magnetic nanoparticles in a 6-hydroxydopamine (6-OHDA)-induced PD mouse model. We used the Maestro imaging system and magnetic resonance imaging (MRI) for in vivo tracking after transplantation of magnetic nanoparticle-loaded hASCs to the PD mouse model. The Maestro imaging system revealed strong hASCs signals in the brains of PD model mice. In particular, MRI revealed hASCs distribution in the substantia nigra of hASCs-injected PD mice. Behavioral evaluations, including apomorphine-induced rotation and rotarod performance, were significantly recovered in hASCs-injected 6-OHDA induced PD mice when compared with saline-treated counterparts. Herein, we investigated whether hASCs transplantation using magnetic nanoparticles recovered motor functions through targeted brain distribution in a 6-OHDA induced PD mice. These results indicate that magnetic nanoparticle-based hASCs transplantation could be a potential therapeutic strategy in PD.

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