Slow relaxation effects at the second-order nematic to lamellar smectic phase transition in micellar liquid crystals

1990 ◽  
Vol 41 (2) ◽  
pp. 954-959 ◽  
Author(s):  
Panos Photinos ◽  
Alfred Saupe
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Smectic Phase ◽  
Second Order ◽  
Slow Relaxation ◽  
Relaxation Effects

Photo-induced guest-host interactions produce chiral conglomerates accompanying grain boundaries in a smectic phase

2021 ◽  
Author(s):  
Hideaki Sasaki ◽  
Koudai Abe ◽  
Masanobu Sagisaka ◽  
Atsushi Yoshizawa
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Physical Properties ◽  
Grain Boundaries ◽  
Smectic Phase ◽  
Host Interactions

Photo-induced isomerization of an azobenzene unit not only induces phase transition between two different phases but also brings marked changes of physical properties in solids and liquid crystals. We prepared...

scholarly journals Statistical Physics Approach to Liquid Crystals: Dynamics of Mobile Potts Model Leading to Smectic Phase, Phase Transition by Wang–Landau Method

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1232
Author(s):  
V. Thanh Ngo ◽  
Phuong-Thuy Nguyen ◽  
Hung T. Diep
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Potts Model ◽  
High Performance ◽  
Statistical Physics ◽  
Film Surface ◽  
Smectic Phase ◽  
Isotropic Phase ◽  
Smectic Liquid Crystals ◽  
Layer By Layer

We study the nature of the smectic–isotropic phase transition using a mobile 6-state Potts model. Each Potts state represents a molecular orientation. We show that with the choice of an appropriate microscopic Hamiltonian describing the interaction between individual molecules modeled by a mobile 6-state Potts spins, we observe the smectic phase dynamically formed when we cool the molecules from the isotropic phase to low temperatures (T). In order to elucidate the order of the transition and the low-T properties, we use the high-performance Wang–Landau flat energy-histogram technique. We show that the smectic phase goes to the liquid (isotropic) phase by melting/evaporating layer by layer starting from the film surface with increasing T. At a higher T, the whole remaining layers become orientationally disordered. The melting of each layer is characterized by a peak of the specific heat. Such a succession of partial transitions cannot be seen by the Metropolis algorithm. The successive layer meltings/evaporations at low T are found to have a first-order character by examining the energy histogram. These results are in agreement with experiments performed on some smectic liquid crystals.

Phase Transition and Dynamics in Imidazolium-Based Ionic Liquid Crystals through a Metastable Highly Ordered Smectic Phase

2016 ◽  
Vol 120 (23) ◽  
pp. 5291-5300 ◽  
Author(s):  
Yoko Nozaki ◽  
Keito Yamaguchi ◽  
Kenji Tomida ◽  
Natsumi Taniguchi ◽  
Hironori Hara ◽  
...  
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Liquid Crystals ◽  
Smectic Phase ◽  
Ionic Liquid Crystals

Void pattern fluctuation in p-AgBr interactions at 400 GeV/c

2016 ◽  
pp. 4115-4125
Author(s):  
Argha Deb
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Phase Space ◽  
Second Order ◽  
Hadron Phase

The event-by-event fluctuation of hadronic patterns is investigated by finding a measure of the non-hadronic regions, the voids, for the experimental data of p-AgBr interactions at 400 GeV/c considering the anisotropy of phase space. Two moments of the event-to-event fluctuation of voids, <Gq> and Sq have been calculated as defined by R. C. Hwa and Q. H. Zhang to quantify the dependence of the voids on the bin sizes. The results suggest that no quark-hadron phase transition of second order have taken place for p-AgBr interactions at 400 GeV/c. The result have been compared with the result of VENUS generated data.

scholarly journals Ion conformation and orientational order in a dicationic ionic liquid crystal studied by solid-state nuclear magnetic resonance spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debashis Majhi ◽  
Sergey V. Dvinskikh
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Crystals ◽  
Bond Order ◽  
Van Der Waals ◽  
Orientational Order ◽  
Smectic Phase ◽  
Side Chains ◽  
Dicationic Ionic Liquid ◽  
Ionic Liquid Crystals

AbstractIonic liquids crystals belong to a special class of ionic liquids that exhibit thermotropic liquid-crystalline behavior. Recently, dicationic ionic liquid crystals have been reported with a cation containing two single-charged ions covalently linked by a spacer. In ionic liquid crystals, electrostatic and hydrogen bonding interactions in ionic sublayer and van der Waals interaction in hydrophobic domains are the main forces contributing to the mesophase stabilization and determining the molecular orientational order and conformation. How these properties in dicationic materials are compared to those in conventional monocationic analogs? We address this question using a combination of advanced NMR methods and DFT analysis. Dicationic salt 3,3′-(1,6-hexanediyl)bis(1-dodecylimidazolium)dibromide was studied. Local bond order parameters of flexible alkyl side chains, linker chain, and alignment of rigid polar groups were analyzed. The dynamic spacer effectively “decouples” the motion of two ionic moieties. Hence, local order and alignment in dicationic mesophase were similar to those in analogous single-chain monocationic salts. Bond order parameters in the side chains in the dicationic smectic phase were found consistently lower compared to double-chain monocationic analogs, suggesting decreasing contribution of van der Waals forces. Overall dication reorientation in the smectic phase was characterized by low values of orientational order parameter S. With increased interaction energy in the polar domain the layered structure is stabilized despite less ordered dications. The results emphasized the trends in the orientational order in ionic liquid crystals and contributed to a better understanding of interparticle interactions driving smectic assembly in this and analogous ionic mesogens.

scholarly journals Emergence and stabilization of transient twisted defect structures in confined achiral liquid crystals at a phase transition.

Soft Matter ◽  
2021 ◽  
Author(s):  
Jose X Velez ◽  
Zhaofei Zheng ◽  
Daniel A. Beller ◽  
Francesca Serra
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Soft Matter ◽  
Capillary Tube ◽  
Nematic Liquid Crystals ◽  
Defect Structures

Spontaneous emergence of chirality is a pervasive theme in soft matter. We report a transient twist forming in achiral nematic liquid crystals confined to a capillary tube with square cross...

Second-order NLO response in chiral ferroelectric liquid crystals: Molecular and bulk consideration

2021 ◽  
pp. 115328
Author(s):  
Stijn van Cleuvenbergen ◽  
Griet Depotter ◽  
Koen Clays ◽  
Przemysław Kędziora
Keyword(s):  
Liquid Crystals ◽  
Second Order ◽  
Ferroelectric Liquid Crystals ◽  
Nlo Response
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