scholarly journals Mesoscale martensitic transformation in single crystals of topological defects

2017 ◽  
Vol 114 (38) ◽  
pp. 10011-10016 ◽  
Author(s):  
Xiao Li ◽  
José A. Martínez-González ◽  
Juan P. Hernández-Ortiz ◽  
Abelardo Ramírez-Hernández ◽  
Ye Zhou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Soft Matter ◽  
Orientational Order ◽  
Topological Defects ◽  
Martensitic Transformations ◽  
Crystal Nucleation ◽  
Ordered Arrays ◽  
Blue Phases ◽  
Theory And Experiments ◽  
Crystalline Array

Liquid-crystal blue phases (BPs) are highly ordered at two levels. Molecules exhibit orientational order at nanometer length scales, while chirality leads to ordered arrays of double-twisted cylinders over micrometer scales. Past studies of polycrystalline BPs were challenged by the existence of grain boundaries between randomly oriented crystalline nanodomains. Here, the nucleation of BPs is controlled with precision by relying on chemically nanopatterned surfaces, leading to macroscopic single-crystal BP specimens where the dynamics of mesocrystal formation can be directly observed. Theory and experiments show that transitions between two BPs having a different network structure proceed through local reorganization of the crystalline array, without diffusion of the double-twisted cylinders. In solid crystals, martensitic transformations between crystal structures involve the concerted motion of a few atoms, without diffusion. The transformation between BPs, where crystal features arise in the submicron regime, is found to be martensitic in nature when one considers the collective behavior of the double-twist cylinders. Single-crystal BPs are shown to offer fertile grounds for the study of directed crystal nucleation and the controlled growth of soft matter.

scholarly journals The exploration of the crystal nucleation parameters and physico-chemical analysis of a single crystal: 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine

RSC Advances ◽  
2021 ◽  
Vol 11 (26) ◽  
pp. 15710-15721
Author(s):  
Paavai Era ◽  
RO. MU. Jauhar ◽  
V. Viswanathan ◽  
M. Madhangi ◽  
G. Vinitha ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Single Crystal ◽  
Chemical Properties ◽  
Crystal Nucleation ◽  
Nucleation Parameters ◽  
Physico Chemical

This paper discusses the structural orientations and the physico-chemical properties of a single crystal of 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine (2ADT).

Topological liquid crystal superstructures as structured light lasers

2021 ◽  
Vol 118 (49) ◽  
pp. e2110839118
Author(s):  
Miha Papič ◽  
Urban Mur ◽  
Kottoli Poyil Zuhail ◽  
Miha Ravnik ◽  
Igor Muševič ◽  
...  
Keyword(s):  
Self Assembly ◽  
Soft Matter ◽  
Structured Light ◽  
Topological Defects ◽  
Photonic Devices ◽  
Light Polarization ◽  
Self Healing ◽  
Fabry Perot ◽  
Self Assembled ◽  
External Stimuli

Liquid crystals (LCs) form an extremely rich range of self-assembled topological structures with artificially or naturally created topological defects. Some of the main applications of LCs are various optical and photonic devices, where compared to their solid-state counterparts, soft photonic systems are fundamentally different in terms of unique properties such as self-assembly, self-healing, large tunability, sensitivity to external stimuli, and biocompatibility. Here we show that complex tunable microlasers emitting structured light can be generated from self-assembled topological LC superstructures containing topological defects inserted into a thin Fabry–Pérot microcavity. The topology and geometry of the LC superstructure determine the structuring of the emitted light by providing complex three-dimensionally varying optical axis and order parameter singularities, also affecting the topology of the light polarization. The microlaser can be switched between modes by an electric field, and its wavelength can be tuned with temperature. The proposed soft matter microlaser approach opens directions in soft matter photonics research, where structured light with specifically tailored intensity and polarization fields could be designed and implemented.

scholarly journals Topology control of human fibroblast cells monolayer by liquid crystal elastomer

2020 ◽  
Vol 6 (20) ◽  
pp. eaaz6485 ◽  
Author(s):  
Taras Turiv ◽  
Jess Krieger ◽  
Greta Babakhanova ◽  
Hao Yu ◽  
Sergij V. Shiyanovskii ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Orientational Order ◽  
Topological Defects ◽  
Density Fluctuations ◽  
Dermal Fibroblasts ◽  
Produce Cell ◽  
Surface Anchoring ◽  
Liquid Crystal Elastomer ◽  
Anisotropic Surface ◽  
Living Tissues

Eukaryotic cells in living tissues form dynamic patterns with spatially varying orientational order that affects important physiological processes such as apoptosis and cell migration. The challenge is how to impart a predesigned map of orientational order onto a growing tissue. Here, we demonstrate an approach to produce cell monolayers of human dermal fibroblasts with predesigned orientational patterns and topological defects using a photoaligned liquid crystal elastomer (LCE) that swells anisotropically in an aqueous medium. The patterns inscribed into the LCE are replicated by the tissue monolayer and cause a strong spatial variation of cells phenotype, their surface density, and number density fluctuations. Unbinding dynamics of defect pairs intrinsic to active matter is suppressed by anisotropic surface anchoring allowing the estimation of the elastic characteristics of the tissues. The demonstrated patterned LCE approach has potential to control the collective behavior of cells in living tissues, cell differentiation, and tissue morphogenesis.

scholarly journals Correction: Spatially heterogeneous dynamics of cells in a growing tumor spheroid: comparison between theory and experiments

Soft Matter ◽  
2020 ◽  
Vol 16 (27) ◽  
pp. 6442-6442
Author(s):  
Sumit Sinha ◽  
Abdul N. Malmi-Kakkada ◽  
Xin Li ◽  
Himadri S. Samanta ◽  
D. Thirumalai
Keyword(s):  
Soft Matter ◽  
Tumor Spheroid ◽  
Heterogeneous Dynamics ◽  
Spatially Heterogeneous Dynamics ◽  
Theory And Experiments

Correction for ‘Spatially heterogeneous dynamics of cells in a growing tumor spheroid: comparison between theory and experiments’ by Sumit Sinha et al., Soft Matter, 2020, 16, 5294–5304, DOI: 10.1039/C9SM02277E.

scholarly journals Liquid crystal elastomer shell actuators with negative order parameter

2019 ◽  
Vol 5 (4) ◽  
pp. eaaw2476 ◽  
Author(s):  
V. S. R. Jampani ◽  
R. H. Volpe ◽  
K. Reguengo de Sousa ◽  
J. Ferreira Machado ◽  
C. M. Yakacki ◽  
...  
Keyword(s):  
Order Parameter ◽  
Soft Matter ◽  
Orientational Order ◽  
Liquid Crystallinity ◽  
Liquid Crystal Elastomer ◽  
Negative Order ◽  
Value Range ◽  
Scalar Order Parameter ◽  
New Challenges ◽  
Soft Matter Physics

Liquid crystals (LCs) are nonsolids with long-range orientational order, described by a scalar order parameter〈P2〉=12〈3cos2β−1〉. Despite the vast set of existing LC materials, one-third of the order parameter value range,−1/2< 〈P2〉 < 0, has until now been inaccessible. Here, we present the first material with negative LC order parameter in its ground state, in the form of elastomeric shells. The optical and actuation characteristics are opposite to those of conventional LC elastomers (LCEs). This novel class of anti-ordered elastomers gives access to the previously secluded range of liquid crystallinity with 〈P2〉 < 0, providing new challenges for soft matter physics and adding a complementary type of LCE actuator that is attractive for applications in, e.g., soft robotics.

Two interferometric methods for the mechanical characterization of thin films by bulging tests. Application to single crystal of silicon

1997 ◽  
Vol 12 (9) ◽  
pp. 2234-2248 ◽  
Author(s):  
E. Bonnotte ◽  
P. Delobelle ◽  
L. Bornier ◽  
B. Trolard ◽  
G. Tribillon
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Mechanical Characterization ◽  
Optical Methods ◽  
Fringe Projection ◽  
Phase Measurements ◽  
Experimental Apparatus ◽  
Theory And Experiments ◽  
Good Agreement

Two optical methods are presented for the mechanical characterization of thin films, namely real time holographic interferometry and a fringe projection method called “contouring.” These two methods are coupled to the interferometry by the phase measurements, thus allowing the displacement field to be measured at all points on the membrane. We discuss the solutions retained in terms of their precision and sensitivity. These methods are then applied to membrane bulging tests, a type of test that is widely used in micro-mechanical studies. The measurements are performed on silicon single crystal and the results are compared to the solutions calculated by finite element methods. In both cases, the good agreement between theory and experiments allows the experimental apparatus to be validated.

Interactions and dynamics of topological defects: Theory and experiments near the onset of weak turbulence

1989 ◽  
Vol 63 (12) ◽  
pp. 1237-1240 ◽  
Author(s):  
Gilad Goren ◽  
Itamar Procaccia ◽  
Steffen Rasenat ◽  
Victor Steinberg
Keyword(s):  
Topological Defects ◽  
Weak Turbulence ◽  
Theory And Experiments
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