Inter‐Nanoparticle Bonds in Agglomerates Studied by Nanoindentation

Raichman, Yulia; Kazakevich, M.; Rabkin, Eugen; Tsur, Yoed

doi:10.1002/adma.200600538

Cited by 42 publications

(23 citation statements)

References 9 publications

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“…Experimental measurements on nanoparticle agglomerates using Atomic Force Microscope (AFM) (Salameh et al, 2014) and nanoindentation (Raichman et al, 2006;Schilde and Kwade, 2012) showed that they are adhesive, and behave as elastic-plastic particles. Significant hysteresis of the forcedisplacement curves is observed when a nanoparticle agglomerate approaches and detaches with a substrate.…”

Section: Adhesive Contact Modelmentioning

confidence: 99%

An adhesive CFD‐DEM model for simulating nanoparticle agglomerate fluidization

et al. 2016

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Nanoparticle fluidization is an efficient technique to disperse and process nanoparticles. Previous studies show that nanoparticles are not fluidized individually, but as agglomerates with hierarchical fractal structures. In this study, an adhesive CFD-DEM (Computational Fluid Dynamics -Discrete Element Modelling) model is developed, in which we use the simple agglomerate as the discrete element, which are the building blocks of the larger complex agglomerates found in a fluidized bed. We show that both the particle contact model and drag force interaction in the conventional CFD-DEM model need modification for properly simulating fluidization of nanoparticle agglomerates. The contact model includes collision mechanisms of elastic-plastic, cohesive and viscoelastic forces, and the drag force is approximately corrected by a scale factor resulting from particle agglomeration. The model is tested for different cases, including the normal impact, response of angle, and fluidization. The simulation results are promising. With increasing particle cohesive force, the fluidized bed goes from a uniform fluid-like regime, to an agglomerate bubbling regime, and finally to defluidization. The current study provides a tool for gaining insights into the characteristics of nanoparticle fluidization.

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Section: Adhesive Contact Modelmentioning

confidence: 99%

An adhesive CFD‐DEM model for simulating nanoparticle agglomerate fluidization

et al. 2016

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“…Basic research on plastic and elastic deformation, as well as breakage of aggregates using nanoindentation were conducted by Kendall and Weihs [22] and Raichman et al [23]. The results of the stress and Figure 4.…”

Section: Measurement Of the Micro-mechanical Propertiesmentioning

confidence: 99%

Effect of Important Precipitation Process Parameters on the Redispersion Process and the Micromechanical Properties of Precipitated Silica

et al. 2009

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In the past, the importance of the industrial mass production of high-quality products and specialty chemicals by precipitation increased rapidly. In the industry, usually larger aggregates are produced and in order to produce colloidal systems with the desired properties, a more or less intense dispersion of the precipitated particles is necessary. The micromechanical properties such as the maximum indentation force, the plastic and elastic deformation energy, and the strength can give information on the product and the efficiency of the dispersion process. Generally, the temperature, as one of the most important parameters of the semibatch precipitation process of silica, was varied in order to change the structure, the primary particle size, the aggregate size, and the primary particle interactions in the aggregates. Dispersion of the precipitated silica in a stirred media mill and a dissolver show that the higher the precipitation temperature, the higher is the product fineness and, thus, the smaller is the strength of the aggregates. The reason for this effect is the increase of the primary particle size and the decrease of the solid bonds with increasing precipitation temperature. Because of higher stress intensities, the product fineness in a stirred media mill is considerably higher than in the dissolver. In principal, the maximum achievable product fineness and the energy efficiency of the dispersion process increase with decreasing particle strength and maximum indentation force. Besides the maximum indentation force, the maximum achievable product fineness and the energy efficiency of the dispersion process increase with increasing quotient of plastic and elastic deformation energy.

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“…Nanoindentation studies on bonded colloidal crystals [162,163] and assemblies [ 164 ] or nanoparticles agglomerates [ 165 ] missed most of the particulate features. A few other works have investigated colloidal ensembles by ultrafast optoacoustic [ 166 ] or microcompression techniques [167,168].…”

Section: Collective Behavior: Mechanical Propertiesmentioning

confidence: 99%

Colloidal crystals and water: Perspectives on liquid–solid nanoscale phenomena in wet particulate media

Gallego-Gómez

Morales‐Flórez

Morales

et al. 2016

Advances in Colloid and Interface Science

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Solid colloidal ensembles inherently contain water adsorbed from the ambient moisture. This water, confined in the porous network formed by the building submicron spheres, greatly affects the ensemble properties. Inversely, one can benefit from such influence on collective features to explore the water behavior in such nanoconfinements. Recently, novel approaches have been developed to investigate in-depth where and how water is placed in the nanometric pores of self-assembled colloidal crystals. Here we summarize these advances, along with new ones, that are linked to general interfacial water phenomena like adsorption, capillary forces and flow. Waterdependent structural properties of the colloidal crystal give clues to the interplay between nanoconfined water and solid fine particles that determines the behavior of ensembles. We elaborate on how the knowledge gained on water in colloidal crystals provides new opportunities for multidisciplinary study of interfacial and nanoconfined liquids and their essential role in the physics of utmost important systems such as particulate media.

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Inter‐Nanoparticle Bonds in Agglomerates Studied by Nanoindentation

Cited by 42 publications

References 9 publications

An adhesive CFD‐DEM model for simulating nanoparticle agglomerate fluidization

An adhesive CFD‐DEM model for simulating nanoparticle agglomerate fluidization

Effect of Important Precipitation Process Parameters on the Redispersion Process and the Micromechanical Properties of Precipitated Silica

Colloidal crystals and water: Perspectives on liquid–solid nanoscale phenomena in wet particulate media

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