Aligning large populations of colloidal nanorods (NRs) into ordered assemblies provides a strategy for engineering macroscopic functional materials with strong optical anisotropy. The bulk optical properties of such systems depend not only on the individual NR building blocks but also on their meso- and macroscale ordering, in addition to more complex interparticle coupling effects. Here, we investigate the dynamic alignment of colloidal CdSe/CdS NRs in the presence of AC electric fields by measuring concurrent changes in optical transmission. Our work identifies two distinct scales of interaction that give rise to the field-driven optical response: (1) the spontaneous mesoscale self-assembly of colloidal NRs into structures with increased optical anisotropy and (2) the macroscopic ordering of NR assemblies along the direction of the applied AC field. By modeling the alignment of NR ensembles using directional statistics, we experimentally quantify the maximum degree of order in terms of the average deviation angle relative to the field axis. Results show a consistent improvement in alignment as a function of NR concentration─with a minimum average deviation of 36.2°─indicating that mesoscale assembly helps facilitate field-driven alignment of colloidal NRs.
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http://dx.doi.org/10.1021/acsnano.1c08488 | DOI Listing |
J Colloid Interface Sci
January 2025
Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8904, Tokyo, Japan; Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8505, Tokyo, Japan. Electronic address:
Phase separation, a fundamental phenomenon in both natural and industrial settings, involves the coarsening of domains over time t to reduce interfacial energy. While well-understood for simple viscous liquid mixtures, the physical laws governing coarsening dynamics in complex fluids, such as colloidal suspensions, remain unclear. Here, we investigate colloidal phase separation through particle-based simulations with and without hydrodynamic interactions (HIs).
View Article and Find Full Text PDFLangmuir
January 2025
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe, Mizuho, Nagoya 467-8603, Aichi, Japan.
In this study, we demonstrate a novel and efficient fabrication methodology for nonclose-packed, two-dimensional (2D) colloidal crystals exhibiting square lattice structures. In our recent work, we detailed the formation of 2D colloidal crystals via the electrostatic adsorption of three-dimensional (3D) charged colloidal crystals onto oppositely charged substrates. These 3D colloidal crystals possessed a face-centered cubic (FCC) lattice structure with their (111) planes aligned parallel to the substrate, facilitating the formation of 2D crystals with triangular lattice arrangements upon adsorption.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Wide-Bandgap Semiconductor Devices and Integrated Technology, Xidian University, Xi'an 710071, PR China.
Commercial SnO nanocrystals used for producing electron transporting layers (ETLs) of perovskite solar cells (PSC) are prone to aggregation at room temperature and contain many structural defects. Herein, we report that the LiOH additive can simultaneously delay the aggregation and donate the beneficial aging effect to SnO nanocrystals. The resulting SnO ETLs show the desired characteristics, including a broadened absorption range, reduced defects, improved transporting properties, and decreased work function.
View Article and Find Full Text PDFBiomolecules
November 2024
Department of Pathology and Medical Biology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
To accelerate cutaneous wound healing and prevent scarring, regenerative approaches such as injecting a mechanically derived tissue stromal vascular fraction (tSVF) are currently under clinical and laboratory investigations. The aim of our study was to investigate a platform to assess the interaction between skin-derived extracellular matrix (ECM) hydrogels and tSVF and their effects on their microenvironment in the first ten days of culture. A tSVF mixed with ECM hydrogel was cultured for ten days.
View Article and Find Full Text PDFSci Rep
January 2025
Cellulose and Paper Department, National Research Centre, 33 El Bohouth Str, P.O. 12622, Dokki Giza, Egypt.
A new method was developed to quickly produce carboxymethyl hemicellulose (CM-Hemi) and fluorescent nitrogen-doped carbon dots (N-CDs) from sugarcane bagasse (SB). These materials were then combined with calcium chloride (CaCl₂) to create hydrogel sensors with antibacterial and antifungal properties. The CM-Hemi@Ca-N-CDs hydrogel was effective against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria compared to CM-Hemi@Ca which give no antibacterial activity.
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