Microstructures and mechanical properties of dense particle gels: Microstructural characterisation

Schenker, Iwan; Filser, Frank; Aste, Tomaso; Gauckler, Ludwig J.

doi:10.1016/j.jeurceramsoc.2007.12.007

Cited by 19 publications

(32 citation statements)

References 21 publications

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“…Modern materials science abounds with explorations into a diverse array of dissipative media (e.g., concentrated emulsions, granular materials, cellular materials, slurries, pastes, and molecular glasses) [1][2][3][4][5][6][7][8]. In part, this broad appeal arises from dissipative media's distinctive mechanical response to applied forces.…”

Section: Introductionmentioning

confidence: 99%

“…In part, this broad appeal arises from dissipative media's distinctive mechanical response to applied forces. On a macroscopic scale, such response often bears the hallmarks of complexity, including self-organization and emergent behavior (e.g., [2][3][4][5][9][10][11][12]). By far the best examples of these patterns of behavior, common in both nature and technology, are those exhibited by dense granular materials under quasistatic loading conditions [10][11][12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Transition dynamics and magic-number-like behavior of frictional granular clusters

et al. 2012

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Force chains, the primary load-bearing structures in dense granular materials, rearrange in response to applied stresses and strains. These self-organized grain columns rely on contacts from weakly stressed grains for lateral support to maintain and find new stable states. However, the dynamics associated with the regulation of the topology of contacts and strong versus weak forces through such contacts remains unclear. This study of local self-organization of frictional particles in a deforming dense granular material exploits a transition matrix to quantify preferred conformations and the most likely conformational transitions. It reveals that favored cluster conformations reside in distinct stability states, reminiscent of "magic numbers" for molecular clusters. To support axial loads, force chains typically reside in more stable states of the stability landscape, preferring stabilizing trusslike, three-cycle contact triangular topologies with neighboring grains. The most likely conformational transitions during force chain failure by buckling correspond to rearrangements among, or loss of, contacts which break the three-cycle topology.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transition dynamics and magic-number-like behavior of frictional granular clusters

et al. 2012

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“…The latter have great technological importance. Colloidal gels find applications in synthetic colloid porous materials (1,2), functionalization of surfaces and films production (3,4), ceramics processing (5,6), protein assemblies (7,8), food science (9,10), and soft matter (11,12). Although they have been known for some time (13,14), it has only recently been understood that the colloidal gels arise as a result of arrested phase separation (15)(16)(17)(18).…”

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confidence: 99%

Arrested demixing opens route to bigels

Varrato

Michele

Belushkin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

107

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Understanding and, ultimately, controlling the properties of amorphous materials is one of the key goals of material science. Among the different amorphous structures, a very important role is played by colloidal gels. It has been only recently understood that colloidal gels are the result of the interplay between phase separation and arrest. When short-ranged attractive colloids are quenched into the phase-separating region, density fluctuations are arrested and this results in ramified amorphous space-spanning structures that are capable of sustaining mechanical stress. We present a mechanism of aggregation through arrested demixing in binary colloidal mixtures, which leads to the formation of a yet unexplored class of materials--bigels. This material is obtained by tuning interspecies interactions. Using a computer model, we investigate the phase behavior and the structural properties of these bigels. We show the topological similarities and the geometrical differences between these binary, interpenetrating, arrested structures and their well-known monodisperse counterparts, colloidal gels. Our findings are supported by confocal microscopy experiments performed on mixtures of DNA-coated colloids. The mechanism of bigel formation is a generalization of arrested phase separation and is therefore universal.spinodal decomposition | DNA-coated colloids | programmable interactions | amorphous self-assembly T he properties of a self-assembled material are ultimately controlled by the interactions among its building blocks and by the conditions in which they are prepared. It is by tuning these two properties that different structures can be obtained. Shortranged attractive colloidal systems, for example, can form crystals, two glasses of different origin, or gels. The latter have great technological importance. Colloidal gels find applications in synthetic colloid porous materials (1, 2), functionalization of surfaces and films production (3, 4), ceramics processing (5, 6), protein assemblies (7, 8), food science (9, 10), and soft matter (11, 12). Although they have been known for some time (13,14), it has only recently been understood that the colloidal gels arise as a result of arrested phase separation (15-18).The gels are characterized by a ramified amorphous spacespanning structure that is capable of sustaining mechanical stress. The colloidal density plays a crucial role in the aggregation and therefore in the resulting structure. At low densities, irreversible aggregation leads to fractal gels. At intermediate densities more compact porous structures are observed, whereas a homogeneous glass emerges when the solute occupies more than 50% of the volume (11,10,14,19).It has been proven that when colloidal particles are quenched into the gas-liquid phase separation region, gelation occurs as a consequence of dynamic arrest that interferes with phase separation (15, 18). After the quench, the system is thermodynamically unstable and strong density fluctuations set in, favoring the separation of the fluid into two ...

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“…6 With some modification the same is possible when the spheres can intersect and have variable diameters. Statistical summary characteristics such as pair-correlation function, 2,4,6,7 Ripley's K-function 6 and bond angle distribution, 7 triangle distribution function, 7 common neighbour distribution, 1 dihedral angle distribution 1 straight path analysis 1 are then appropriate tools. They all characterize in various ways the relative positions of the spheres or objects.…”

Section: Introductionmentioning

confidence: 99%