Preparation and yielding behavior of pendular network suspensions

Yang, Junyi; Velankar, Sachin

doi:10.1122/1.4973962

Cited by 21 publications

(19 citation statements)

References 55 publications

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“…This behaviour is characteristic for pendular state samples. 29,31,50 As was previously hypothesised and confirmed with confocal images, 22,46 the stress increase at relatively low amounts of secondary fluid should appear due to the buildup of binary capillary bridges, where the maximum is attributed to a coalescence of adjacent bridges, termed the funicular state. The decrease for relatively high amounts of secondary fluid is explained by the formation of large and dense particle agglomerates (e.g.…”

Section: Connecting Microstructure and Rheologysupporting

confidence: 52%

Connecting particle clustering and rheology in attractive particle networks

et al. 2020

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Section: Connecting Microstructure and Rheologysupporting

confidence: 52%

Connecting particle clustering and rheology in attractive particle networks

et al. 2020

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“…merged capillary bridges [26, 70], while the ensuing decrease occurs due to the formation of larger dense agglomerates, which lead to a weakening of the network structure [5, 9]. The details of yield stress dependence on second fluid content have already been thoroughly investigated by Dittmann et al on the same sample system [9], and are a general characteristics of pendular state capillary suspensions [71].…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, a mixed contribution of both effects is likely to appear. Accordingly, ϕ sec / ϕ solid has already been used as relevant property involved in structural transitions of capillary suspensions in other studies [5, 20, 65, 71]. The transition from the yield stress increase to the maximum plateau value at ϕ sec / ϕ solid ≈ 0.02–0.04 agrees well with the ratio of single bridge to particle volumes V bridge / V particle = 0.021–0.025 where the pendular-to-funicular transition was calculated for glass bead based capillary suspensions with contact angles in the range of θ = 40–61° [26].…”

Section: Resultsmentioning

confidence: 99%

Fractal approaches to characterize the structure of capillary suspensions using rheology and confocal microscopy

Bossler

Maurath

Dyhr

et al. 2018

Journal of Rheology

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The rheological properties of a particle suspension can be substantially altered by adding a small amount of a secondary fluid that is immiscible with the bulk phase. The drastic change in the strength of these capillary suspensions arises due to the capillary forces, induced by the added liquid, leading to a percolating particle network. Using rheological scaling models, fractal dimensions are deduced from the yield stress and from oscillatory strain amplitude sweep data as function of the solid volume fraction. Exponents obtained using aluminum-oxide-based capillary suspensions, with a preferentially wetting secondary fluid, indicate an increase in the particle gel's fractal dimension with increasing particle size. This may be explained by a corresponding relative reduction in the capillary force compared to other forces. Confocal images using a glass model system show the microstructure to consist of compact particle flocs interconnected by a sparse backbone. Thus, using the rheological models two different fractal dimensionalities are distinguished - a lower network backbone dimension ( = 1.86-2.05) and an intrafloc dimension ( = 2.57-2.74). The latter is higher due to the higher local solid volume fraction inside of the flocs compared to the sparse backbone. Both of these dimensions are compared with values obtained by analysis of spatial particle positions from 3D confocal microscopy images, where dimensions between 2.43 and 2.63 are computed, lying between the two dimension ranges obtained from rheology. The fractal dimensions determined via this method corroborate the increase in structural compactness with increasing particle size.

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“…This behaviour is characteristic for pendular state samples. [14,45,6] As was previously hypothesised and confirmed with confocal images, [28,5] the stress increase at relatively low amounts of secondary fluid should appear due to the buildup of binary capillary bridges, where the maximum is attributed to a coalescence of adjacent bridges, termed the funicular state. The decrease for relatively high amounts of secondary fluid is explained by the formation of large and dense particle agglomerates that begin to destabilise the structure.…”

Section: Resultsmentioning

confidence: 53%

Connecting particle clustering and rheology in attractive particle networks

Bindgen,

Bossler,

Allard

et al. 2020

Preprint

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The structural properties of suspensions and other multiphase systems are vital to overall processability, functionality and acceptance among consumers. Therefore, it is crucial to understand the intrinsic connection between the microstructure of a material and the resulting rheological properties. Here, we demonstrate how the transitions in the microstructural conformations can be quantified and correlated to rheological measurements. We find semi-local parameters from graph theory, the mathematical study of networks, to be useful in linking structure and rheology. Our results, using capillary suspensions as a model system, show that the use of the clustering coefficient, in combination with the coordination number, is able to capture not only the agglomeration of particles, but also measures the formation of groups. These phenomena are tightly connected to the rheological properties.

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Preparation and yielding behavior of pendular network suspensions

Cited by 21 publications

References 55 publications

Connecting particle clustering and rheology in attractive particle networks

Connecting particle clustering and rheology in attractive particle networks

Fractal approaches to characterize the structure of capillary suspensions using rheology and confocal microscopy

Connecting particle clustering and rheology in attractive particle networks

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