We report the elaboration of supercrystals made up of dodecanoic acid-coated 8.1 nm-Co nanocrystals with controlled supercrystallinity, morphology and magnetic properties. Supercrystal growth is controlled using a solvent-mediated ligand-ligand interaction strategy. Either face-centered cubic supercrystalline films or single colloidal crystals composed of cobalt nanocrystals are obtained. The change in supercrystal morphology is explained by Flory-type solvation theory using Hansen solubility colloidal parameters. The use of the same batch of Co nanocrystals for the fabrication of supercrystalline films and colloidal crystals enables accurate comparative structural and magnetic studies using (high-resolution) transmission electron microscopy, field emission gun scanning electron microscopy, grazing incidence small-angle X-ray scattering and vibrating sample magnetometry. The nearest neighbor distance between nanoparticles is interpreted using theoretical models proposed in the literature. We evidence the increase in both geometric anisotropy and magnetic dipolar interactions for colloidal crystals compared to supercrystalline films.
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http://dx.doi.org/10.1039/d0nr05517d | DOI Listing |
Phys Chem Chem Phys
January 2025
State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Mechanoresponsive colloidal photonic crystals embedded in elastic solid matrices exhibit tunable optical properties under mechanical force, showing great potential for various applications. However, the response of colloidal crystals embedded in a liquid matrix remains largely unexplored. In this study, we investigate the structural and optical transitions of colloidal crystals composed of particles suspended in a liquid oligomer under pressing and shear forces.
View Article and Find Full Text PDFSoft Matter
January 2025
Departamento de Estructura de la Materia, Física Térmica y Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
The effect of gravity on the collective motion of living microswimmers, such as bacteria and micro-algae, is pivotal to unravel not only bio-convection patterns but also the settling of bacterial biofilms on solid surfaces. In this work, we investigate suspensions of microswimmers under the influence of a gravitational field and hydrodynamics, simulated the dissipative particle dynamics (DPD) coarse-grained model. We first study the collective sedimentation of passive colloids and microswimmers of the puller and pusher types upon increasing the imposed gravitational field and compare them with previous results.
View Article and Find Full Text PDFAdv Mater
January 2025
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, 215123, China.
Formamidinium lead iodide (FAPbI) perovskite films, ensuring optically active phase purity with uniform crystal orientation, are ideal for photovoltaic applications. However, the optically active α-FAPbI phase is easy to degrade into δ-phase due to numerous defects within randomly oriented films. Here, a "quasi-2D" perovskite template is pre-deposited on the film surface within the crystallization process based on the two-step preparation technology, which directly induced pure and highly orientated crystallization of α-FAPbI across the downward growth process.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemistry, School of Science, Westlake University, Hangzhou, Zhejiang Province, China.
The self-assembly of small molecules through non-covalent interactions is an emerging and promising strategy for building dynamic, stable, and large-scale structures. One remaining challenge is making the non-covalent interactions occur in the ideal positions to generate strength comparable to that of covalent bonds. This work shows that small molecule YAWF can self-assemble into a liquid-crystal hydrogel (LCH), the mechanical properties of which could be controlled by water.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Institute of Health Sciences, China Medical University, Shenyang 110122, China. Electronic address:
A flexible cotton-based Ag/AgPO/MXene (APMX) ternary composite material was successfully synthesized, serving as a dual-function and reusable surface-enhanced Raman scattering (SERS) substrate for both sensitive detection and efficient organic dye degradation. The remarkable SERS properties of the composite can be attributed to the combined effects of electromagnetic enhancement by Ag nanoparticles (Ag NPs), charge transfer enhancement from AgPO, and the chemical enhancement mechanisms associated with MXene. When employed for the detection of crystal violet (CV), the material exhibits outstanding sensitivity, achieving a limit of detection (LOD) as low as 3.
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