We show that forces between two colloidal particles in a thin layer of a chiral nematic liquid crystal strongly depend on the chirality of the liquid crystal. The observed pair potentials are attractive, but are oscillatory functions of colloidal separation. The number and the position of local energy minima increase with increasing chirality. The pair interaction is the strongest for the pitch equal to the colloidal diameter and decreases with increasing chirality. We show that the chirality of the medium is responsible for this oscillatory nature and screening of the colloidal interaction in the far and near field. The measurements are in agreement with numerical calculations using Landau-de Gennes theory.
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http://dx.doi.org/10.1103/PhysRevLett.110.177801 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Xiangtan University, College of Chemistry, CHINA.
Efficient circularly polarized luminescence (CPL) optical waveguides have significant potential for advancing photonic and optoelectronic devices. However, the development of CPL optical waveguides materials (OWMs) with low optical loss coefficient remains a considerable challenge. To overcome this, we design and synthesize CPL OWMs based on room-temperature phosphorescent liquid crystalline polymers (LCPs).
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Chemical and Biological Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada. Electronic address:
This study explores the effect of sucrose addition on the properties of chiral nematic cellulose nanocrystal (CNC) films for potential food industry applications, including biodegradable packaging and food coloring. The addition of sucrose altered the films' structural color, shifting from blue in pure CNC films to aqua blue, green, yellow-green, and red with increasing sucrose concentrations (up to 21 %). Surface analysis revealed a reduction in contact angle from 96° to 48° due to sucrose's hydrophilic nature and smoother film surfaces.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China. Electronic address:
Multidirectional strain sensors are of technological importance for wearable devices and soft robots. Here, we report that flexible materials capable of multidirectional anisotropic strain sensing can be constructed leveraging diffusion-induced infiltration of monomers and in situ polymerization of metal ion-containing double network hydrogels in and on the surface of micro-corrugated chiral nematic cellulose nanocrystal/glucose films. Integrating the micro-corrugated cellulose nanocrystal/glucose chiral nematic films with ionic conductive hydrogels of PAA-co-AAm/sodium alginate/Al endows the materials with multidirectional mechanoelectrical resistivity and mechanochromism anisotropy.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden; Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden. Electronic address:
Hypothesis: Charge-stabilized colloidal cellulose nanocrystals (CNCs) can self-assemble into higher-ordered chiral nematic structures by varying the volume fraction. The assembly process exhibits distinct dynamics during the isotropic to liquid crystal phase transition, which can be elucidated using X-ray photon correlation spectroscopy (XPCS).
Experiments: Anionic CNCs were dispersed in propylene glycol (PG) and water spanning a range of volume fractions, encompassing several phase transitions.
Phys Rev Lett
December 2024
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China.
We show that spontaneous density segregation in dense systems of aligning circle swimmers is a condensation phenomenon at odds with the phase separation scenarios usually observed in two-dimensional active matter. The condensates, which take the form of vortices or rotating polar packets, can absorb a finite fraction of the particles in the system, and keep a finite or slowly growing size as their mass increases. Our results are obtained both at particle and continuous levels.
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