A5015530349- Liquid Crystal Research Advancements
- Photonic Crystals and Applications
- Advanced Materials and Mechanics
- Pickering emulsions and particle stabilization
- Theoretical and Computational Physics
- Mechanical and Optical Resonators
- Nanowire Synthesis and Applications
- Surfactants and Colloidal Systems
- Graphene research and applications
- Quantum Dots Synthesis And Properties
- Granular flow and fluidized beds
- Nonlinear Dynamics and Pattern Formation
- Scientific Research and Discoveries
- Phase-change materials and chalcogenides
- Molecular spectroscopy and chirality
- Fluid Dynamics and Thin Films
- Gold and Silver Nanoparticles Synthesis and Applications
- 2D Materials and Applications
- Planetary Science and Exploration
Case Western Reserve University
2022-2023
Institut des NanoSciences de Paris
2017-2022
Centre National de la Recherche Scientifique
2017-2022
Otto-von-Guericke University Magdeburg
2020-2022
Sorbonne Université
2017-2022
Centre de Nanosciences et de Nanotechnologies
2018
Université Paris-Saclay
2018
Université Paris-Sud
2018
Semiconducting 2D materials, such as transition metal dichalcogenides (TMDs), are emerging in nanomechanics, optoelectronics, and thermal transport. In each of these fields, perfect control over material properties including strain, doping, heating is necessary, especially on the nanoscale. Here, we study clean devices consisting membranes single-layer MoS2 suspended pillar arrays. Using Raman photoluminescence spectroscopy, have been able to extract, separate simulate different...
In this Letter, we show how advanced hierarchical structures of topological defects in the so-called smectic oily streaks can be used to sequentially transfer their geometrical features gold nanospheres. We use two kinds defects, 1D dislocations and 2D ribbon-like defects. The large trapping efficiency dislocation cores not only surpasses that elastically distorted zones around but also one defect. This enables formation a number aligned NP chains within quasi-fully filled without any...
New collective optical properties have emerged recently from organized and oriented arrays of closely packed semiconducting metallic nanoparticles (NPs). However, it is still challenging to obtain NP assemblies which are similar everywhere on a given sample and, most importantly, share unique common orientation that would guarantee behavior the sample. In this context, by combining microscopy, fluorescence microscopy synchrotron-based grazing incidence X-ray scattering (GISAXS) gold...
The authors show that mutual orientations of the defects as well alignment pair respective to far director field are essential parameters describing annihilation dynamics in liquid crystals.
Thin smectic liquid crystal films with competing boundary conditions (planar and homeotropic at opposing surfaces) form well-known striated structures known as “oily streaks”, which are a series of hemicylindrical caps that run perpendicular to the easy axis planar substrate. The streaks vanish on heating into nematic phase, where film becomes uniform exhibits hybrid alignment. On adding sufficient reactive mesogen polymerizing, oily streak texture is maintained through entire phase until...
The recent emergence of strain gradient engineering directly affects the nanomechanics, optoelectronics and thermal transport fields in 2D materials. More specifically, large suspended graphene under very high stress represents quintessence for nanomechanical mass detection through unique molecular reactions. Different techniques have been used to induce materials, instance by applying tip indentation, pressure or substrate bending on a membrane. Nevertheless, an efficient way control...
Freely suspended films in the smectic C phase are excellent templates for study of topological defect dynamics. It is well known that, during annihilation a pair disclinations with strengths +/−1, +1 moves faster because it carried towards its opponent by backflow, whereas flow vicinity −1 negligibly small. This backflow pattern created motion itself. An experimental confirmation this theoretical prediction and quantitative characterization achieved here fluorescence labeling. Film regions...
Liquid Crystal (LC) topological defects have been shown to trap nanoparticles (NPs) in the defect cores. The LC may thus be used as a matrix for new kinds of NP organizations templated by geometry. We here study composites smectic dislocations and gold NPs. Straight chains parallel are obtained leading highly anisotropic optical absorption NPs controlled light polarization. Combining Grazing Incidence Small Angle X-ray scattering (GISAXS), Rutherford Back Scattering (RBS), Spectrophotometry...
<title>Abstract</title> Understanding structure-property-process relationship aka rheology of regolith in varying gravity conditions is critical for exploration and future missions. In this work, a framework studying lunar simulant (Terrestrial, Lunar Martian) described theoretically/numerically, where the driving force flow simulants was gravitational acceleration. analysis particle-particle interaction forces were included. It found that dynamic behavior granular material extremely...
A wedge cell made of homeotropically treated glass plates is filled with a chirally doped nematic liquid crystal. When sufficiently large magnetic field applied in the plane, bend-like distortion occurs above Fréedericksz threshold Hth. Hth reduced from achiral case because field-induced bend that facilitates chiral twist distortion. Measurements vs sample thickness are reported and compared favorably theoretical model presented herein. further comparison between electric-field-induced...
A thin Smectic-A liquid crystal (LC) film is deposited on a polymer vinyl alcohol-coated substrate that had been scribed with uniform easy axis pattern over square of side length L ≤ 85 μm. The small size the patterned region facilitates material distribution to form either hill (for film) or divot thick above and having an oily streak (OS) texture. Optical profilometry measurements vs. thickness suggest OS structure aims adopt preferred z0 depends nature molecule, temperature, surface...
Smectic liquid crystals are fluids, and in most rheological situations they behave as such. Nevertheless, when thin freely floating films of smectic A or C materials compressed quickly in-plane, resist such stress by buckling similar to solid membranes under lateral stress. We report experimental observations wrinkling bulging finite domains within the films, so-called islands, give a qualitative explanation different observed patterns. Depending on external their dimensions, islands can...