Thermotropic properties of monosubstituted ferrocene derivatives bearing bidentateN-benzoyl-N′-arylthiourea ligands—novel building blocks for heterometallic liquid crystal systems

1998 ◽  
Vol 8 (6) ◽  
pp. 1345 ◽  
Author(s):  
Tarimala Seshadri ◽  
Hans-jürgen Haupt
Keyword(s):  
Liquid Crystal ◽  
Building Blocks ◽  
Ferrocene Derivatives ◽  
Thermotropic Properties

Reversible microscale assembly of nanoparticles driven by the phase transition of a thermotropic liquid crystal

2017 ◽  
Author(s):  
Niamh Mac Fhionnlaoich ◽  
Stephen Schrettl ◽  
Nicholas B. Tito ◽  
Ye Yang ◽  
Malavika Nair ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Self Assembly ◽  
Nematic Phase ◽  
Hierarchical Control ◽  
Building Blocks ◽  
Model System ◽  
Microscopic Level ◽  
Reversible Process ◽  
Thermotropic Liquid Crystal

The arrangement of nanoscale building blocks into patterns with microscale periodicity is challenging to achieve via self-assembly processes. Here, we report on the phase transition-driven collective assembly of gold nanoparticles in a thermotropic liquid crystal. A temperature-induced transition from the isotropic to the nematic phase leads to the assembly of individual nanometre-sized particles into arrays of micrometre-sized aggregates, whose size and characteristic spacing can be tuned by varying the cooling rate. This fully reversible process offers hierarchical control over structural order on the molecular, nanoscopic, and microscopic level and is an interesting model system for the programmable patterning of nanocomposites with access to micrometre-sized periodicities.

Thermotropic properties of ferrocene derivatives bearing a cholesteryl unit: structure-properties correlations

2005 ◽  
Vol 19 (9) ◽  
pp. 1022-1037 ◽  
Author(s):  
Daniela Apreutesei ◽  
Gabriela Lisa ◽  
Hiroki Akutsu ◽  
Nicolae Hurduc ◽  
Shin'ichi Nakatsuji ◽  
...  
Keyword(s):  
Ferrocene Derivatives ◽  
Unit Structure ◽  
Thermotropic Properties ◽  
Structure Properties

scholarly journals Electrically powered motions of toron crystallites in chiral liquid crystals

2020 ◽  
Vol 117 (12) ◽  
pp. 6437-6445 ◽  
Author(s):  
Hayley R. O. Sohn ◽  
Ivan I. Smalyukh
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Soft Matter ◽  
Building Blocks ◽  
Rigid Particles ◽  
Deformable Particle ◽  
External Stresses ◽  
Oscillating Electric Field ◽  
Experimental Geometry ◽  
Chiral Liquid Crystals

Malleability of metals is an example of how the dynamics of defects like dislocations induced by external stresses alters material properties and enables technological applications. However, these defects move merely to comply with the mechanical forces applied on macroscopic scales, whereas the molecular and atomic building blocks behave like rigid particles. Here, we demonstrate how motions of crystallites and the defects between them can arise within the soft matter medium in an oscillating electric field applied to a chiral liquid crystal with polycrystalline quasi-hexagonal arrangements of self-assembled topological solitons called “torons.” Periodic oscillations of electric field applied perpendicular to the plane of hexagonal lattices prompt repetitive shear-like deformations of the solitons, which synchronize the electrically powered self-shearing directions. The temporal evolution of deformations upon turning voltage on and off is not invariant upon reversal of time, prompting lateral translations of the crystallites of torons within quasi-hexagonal periodically deformed lattices. We probe how these motions depend on voltage and frequency of oscillating field applied in an experimental geometry resembling that of liquid crystal displays. We study the interrelations between synchronized deformations of the soft solitonic particles and their arrays, and the ensuing dynamics and giant number fluctuations mediated by motions of crystallites, five–seven defects pairs, and grain boundaries in the orderly organizations of solitons. We discuss how our findings may lead to technological and fundamental science applications of dynamic self-assemblies of topologically protected but highly deformable particle-like solitons.

Synthesis and thermotropic properties of new green electrochromic ionic liquid crystals

2019 ◽  
Vol 43 (46) ◽  
pp. 18285-18293 ◽  
Author(s):  
Lucia Veltri ◽  
Gabriella Cavallo ◽  
Amerigo Beneduci ◽  
Pierangelo Metrangolo ◽  
Giuseppina Anna Corrente ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Small Molecules ◽  
Ionic Liquid Crystals ◽  
Thermotropic Properties

New liquid crystal viologens, which exhibit green electrochromic behavior in the LC phase, rarely observed for small molecules, have been developed.

scholarly journals Experimental Investigation of the Transition to Spatiotemporal Chaos with a System-Size Control Parameter

2008 ◽  
Vol 2008 ◽  
pp. 1-5
Author(s):  
Daniel R. Spiegel ◽  
Elliot R. Johnson
Keyword(s):  
Liquid Crystal ◽  
Control Parameter ◽  
Quantitative Measure ◽  
Building Blocks ◽  
System Size ◽  
Spatiotemporal Chaos ◽  
Length Scale ◽  
Fourth Moment ◽  
Pattern Size ◽  
Temporal Periodicity

Using a localized laser-heating method to allow the use of system size as a control parameter, we experimentally investigate, using liquid-crystal electroconvection with soft boundary conditions, the onset of spatial temporal chaos (STC) with increasing system size. We find that temporal periodicity is significantly quenched as the system size increases. The increase of the fourth moment (kurtosis) of the temporal Fourier transform provides a very useful quantitative measure of the loss of temporal periodicity (hence the onset of STC) as the pattern size increases, and also provides a simple means for determining a natural chaotic length scale. This length scale is comparable to the length of vertical rows observed in the original pattern. Our experiments, thus, imply that there are well-defined building blocks, which in our case are easily visualized, that control the dynamics in STC liquid crystal convection. The results of our experiments appear to be consistent with the conclusions of recent STC computer simulations carried out by Fishman and Egolf.

scholarly journals Liquid-crystal-based topological photonics

2021 ◽  
Vol 118 (4) ◽  
pp. e2020525118
Author(s):  
Hamed Abbaszadeh ◽  
Michel Fruchart ◽  
Wim van Saarloos ◽  
Vincenzo Vitelli
Keyword(s):  
Liquid Crystal ◽  
Geometric Phase ◽  
Soft Matter ◽  
Light Propagation ◽  
Orientational Order ◽  
Building Blocks ◽  
Photonic Materials ◽  
Nematic Director ◽  
Optical Axes ◽  
Topological States

Liquid crystals are complex fluids that allow exquisite control of light propagation thanks to their orientational order and optical anisotropy. Inspired by recent advances in liquid-crystal photo-patterning technology, we propose a soft-matter platform for assembling topological photonic materials that holds promise for protected unidirectional waveguides, sensors, and lasers. Crucial to our approach is to use spatial variations in the orientation of the nematic liquid-crystal molecules to emulate the time modulations needed in a so-called Floquet topological insulator. The varying orientation of the nematic director introduces a geometric phase that rotates the local optical axes. In conjunction with suitably designed structural properties, this geometric phase leads to the creation of topologically protected states of light. We propose and analyze in detail soft photonic realizations of two iconic topological systems: a Su–Schrieffer–Heeger chain and a Chern insulator. The use of soft building blocks potentially allows for reconfigurable systems that exploit the interplay between topological states of light and the underlying responsive medium.

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