Uniaxially anisotropic chitin-silica nanocomposite solids have been obtained thanks to the electric field-induced macroscopic alignment of liquid-crystalline reactive cosuspensions. We demonstrate how chitin nanorods (260 nm long, 23 nm thick) can be aligned upon the application of an alternating current (ac) electric field, and within water-ethanol suspensions containing reactive siloxane oligomers (D(h) ∼ 3 nm). The alignment at the millimeter length scale is monitored by in situ small-angle X-ray scattering (SAXS) and polarized light optical microscopy. The composition and state (isotropic, chiral nematic) of the cosuspensions are proven to be determining factors. For nematic phases, the alignment is preserved when the electric field is switched off. Further solvent evaporation induces sol-gel transition, and uniaxially anisotropic chitin-silica nanocomposites are formed after complete drying of the aligned nematic suspensions. Here, the collective response of colloidal mesophases to external electric fields and the subsequent formation of ordered nanocomposite solids would represent a new opportunity for materials design.
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http://dx.doi.org/10.1021/la401448e | DOI Listing |
Materials (Basel)
January 2025
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China.
Sensors (Basel)
December 2024
School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China.
In the case of waveguide-based devices, once they are fabricated, their optical properties are already determined and cannot be dynamically controlled, which limits their applications in practice. In this paper, an isosceles triangular-coupling structure which consists of an isosceles triangle coupled with a two-bus waveguide is proposed and researched numerically and theoretically. The coupled mode theory (CMT) is introduced to verify the correctness of the simulation results, which are based on the finite difference time domain (FDTD).
View Article and Find Full Text PDFMolecules
December 2024
Faculty of Physics, Alexandru Ioan Cuza University, 11 Carol I Blvd, RO-700506 Iasi, Romania.
A rapid and simple spectral method for determining the linear birefringence of thin anisotropic films, using the channeled spectra, is proposed in this article. Two channeled spectra must be recorded for a transparent system containing a thick anisotropic layer and a thin stretched polymer film, when the two anisotropic uniaxial layers have parallel and perpendicular optical axes, respectively. The sum and difference of the two channeled spectra indicate (by the positions of the maxima and minima in the resulting channeled spectra) the phase difference introduced by the thin polymer film.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Out of Equilibrium Group, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India.
In biological systems such as cells, the macromolecules, which are anisotropic particles, diffuse in a crowded medium. In the present work, we have studied the diffusion of spheroidal particles diffusing between cylindrical obstacles by varying the density of the obstacles as well as the spheroidal particles. Analytical calculation of the free energy showed that the orientational vector of a single oblate particle will be aligned perpendicular, and a prolate particle will be aligned parallel to the symmetry axis of the cylindrical obstacles in equilibrium.
View Article and Find Full Text PDFACS Biomater Sci Eng
January 2025
Department of Cell Engineering, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 16635-148, Iran.
To enhance therapeutic strategies for cardiovascular diseases, the development of more reliable in vitro preclinical systems is imperative. These models, crucial for disease modeling and drug testing, must accurately replicate the 3D architecture of native heart tissue. In this study, we engineered a scaffold with aligned poly(lactic--glycolic acid) (PLGA) microfilaments to induce cellular alignment in the engineered cardiac microtissue (ECMT).
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