Hypothesis: Understanding the stability and rheological behavior of suspensions composed of anisotropic particles is challenging due to the complex interplay of hydrodynamic and colloidal forces. We propose that orientationally-dependent interactions resulting from the anisotropic nature of non-spherical sub-units strongly influences shear-induced particle aggregation/fragmentation and suspension rheological behavior.
Experiments: Wide-, small-, and ultra-small-angle X-ray scattering experiments were used to simultaneously monitor changes in size and fractal dimensions of boehmite aggregates from 6 to 10,000 Å as the sample was recirculated through an in-situ capillary rheometer. The latter also provided simultaneous suspension viscosity data. Computational fluid dynamics modeling of the apparatus provided a more rigorous analysis of the fluid flow.
Findings: Shear-induced aggregation/fragmentation was correlated with a complicated balance between hydrodynamic and colloidal forces. Multi-scale fractal aggregates formed in solution but the largest could be fragmented by shear. Orientationally-dependent interactions lead to a relatively large experimental suspension viscosity when the hydrodynamic force was small compared to colloidal forces. This manifests even at low boehmite mass fractions.
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http://dx.doi.org/10.1016/j.jcis.2020.04.016 | DOI Listing |
J Hazard Mater
December 2024
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address:
Understanding the behavior and fate of microplastics (MPs) in aquatic environment is crucial for assessing their potential risks. This study investigated the heteroaggregation behaviors of MPs with representative 2D nanosheets, MoS and graphene oxide (GO), under various conditions, focusing on the transport behavior of the resulting aggregates. It was found that the destabilization capabilities of 2D nanosheets are notably stronger than those of well-reported nanoparticles.
View Article and Find Full Text PDFNano Lett
January 2025
College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China.
The net charge of individual nanoparticles in nonpolar solvents plays a critical role in their intrinsic properties like charge carrier lifetime, electron transport, and interparticle interactions. However, there is a long-standing belief that the oil-dispersed nanoparticles inherently possess no net charge. This work presents an approach for directly quantifying the net charge of individual nanoparticles.
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY 14260, USA.
Langmuir
January 2025
Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Műegyetem rkp. 3, 1111 Budapest, Hungary.
During the experimental formation of sol-gel coatings, the colloid dispersions go through a drying process, and the structure of the coatings is formed as a result of complex chemical, colloidal, and capillary interactions. While computer simulations provide guidelines to tune and even design the nanomaterials synthesis, simulations of coating structure formation are hitherto unknown in the literature. Based on real experiments, we establish here a ReaxFF reactive force field-based molecular dynamics simulation protocol in order to investigate and determine the role of the experimental conditions on the pore structure formation in the coatings.
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January 2025
Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education of the P. R. China, Shandong University, Jinan, 250100, P. R. China.
The dual-site electrocatalysts formed by metal single atoms combines with metal nanoparticles represent a promising strategy to enhance both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance. Herein, defect engineering is applied to dual-site ORR and OER electrocatalysts. Its design, synthesis, structural properties, and catalytic performance experimentally and theoretically are insightfully studied for the single-atomic Fe─N and the adjacent FeCo nanoalloy (FeCo) as dual-site loading on nitrogen-doped graphene aerogel (Fe─N/FeCo@NGA).
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