Dynamics and Rheology of Soft Colloidal Glasses

Wen, Yu; Schaefer, Jennifer L.; Archer, Lynden A.

doi:10.1021/mz5006662

Cited by 31 publications

(28 citation statements)

References 49 publications

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“…An effective noise temperature x, that is used to describe the interaction between different elements, controls the jamming extent and determines the rheological response of relaxation dynamics 30,50,53 . That is, for x > 3, the system exhibits Maxwell-like liquid behaviour, and for 1 < x < 3, the model predicts G  , as is the case for the low frequency dynamics (see Figure 3b).…”

Section: Linear Viscoelasticitymentioning

confidence: 99%

Interfacial Particle Dynamics: One and Two Step Yielding in Colloidal Glass

Zhang

Cayre

et al. 2016

Langmuir

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The yielding behaviour of silica nanoparticles partitioned at an air-aqueous interface is reported. Linear viscoelasticity of the particle-laden interface can be retrieved via a timedependent and electrolyte-dependent superposition, and the applicability of the 'soft glassy rheology' (SGR) model is confirmed. With increasing electrolyte concentration a non-ergodic state is achieved with particle dynamics arrested firstly from attraction induced bonding bridges and then from the cage effect of particle jamming, manifesting in a two-step yielding process under large amplitude oscillation strain (LAOS). The Lissajous curves disclose a shear-induced in-cage particle re-displacement within oscillation cycles between the two yielding steps, exhibiting a 'strain softening' transitioning to 'strain stiffening' as the interparticle attraction increases. By varying and the particle spreading concentration, , a variety of phase transitions from fluid-to gel-and glass-like can be unified to construct a state diagram mapping the yielding behaviors from one-step to two-step before finally exhibiting one-step yielding at high and .

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Section: Linear Viscoelasticitymentioning

confidence: 99%

Interfacial Particle Dynamics: One and Two Step Yielding in Colloidal Glass

Zhang

Cayre

et al. 2016

Langmuir

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“…Chain conformations are thought to depend strongly on both grafting density and surface curvature, but such dependence is not well‐established due to a lack of direct experimental verification. Although, there has recently been marked rise in investigations probing the dynamics of PGNPs in polymer matrices, the effort on single‐component PGNPs is more limited both for experiments and simulations . Surprisingly, the study of neat PGNP structure is even more limited than is the study of neat PGNP dynamics.…”

Section: Introductionmentioning

confidence: 99%

Scaling Laws for Polymer Chains Grafted onto Nanoparticles

Yang

Kim

Wang

et al. 2018

Macro Chemistry & Physics

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An experimental approach is presented for identifying the scaling laws for polymer chains grafted onto gold nanoparticles. Poly(ethylene oxide) of various molecular weights are grafted onto gold nanoparticles via thiol end‐functional groups. The polymer‐grafted nanoparticles are self‐assembled into monolayers from solvents of different quality. Over a significant range of graft densities, nanoparticle monolayers deposited from good (athermal) solvent exhibit particle spacing that scales according to theoretical predictions for chains in dilute solution. This unexpected result for ordered nanoparticle monolayers is discussed in the context of the deposition process. In monolayers deposited from theta solvent, molecular weight scaling of particle spacing breaks down, possibly due to chain length dependence of solvent quality. In poor solvent, the structure of nanoparticle assemblies is not sufficiently ordered to obtain reliable measurements, possibly due to loss of nanoparticle dispersion. This approach opens up the possibility for accurate measurement of the effect of solvent on grafted chain scaling in nanoparticle assemblies.

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“…In colloidal suspensions, [31][32][33][34] there is competition between cage-rattling and cage breaking mechanisms that leads to shallow relaxations at short times and quasiexponential decays at long times. [35][36][37][38][39][40] In polymer systems, 41 polymer segments relax subdiffusively through Zimm or Rouse motion before the chain moves diffusively so that the stress response decays as a power-law on short time scales followed by an exponential at long times. [42][43][44] We observe a similar complex response in the stress relaxation of the WLM emulsions and choose to model the stress relaxation through an analogous process (Fig.…”

Section: Wlm Emulsionmentioning

confidence: 99%

Correlation of droplet elasticity and volume fraction effects on emulsion dynamics

Poling-Skutvik

2020

Soft Matter

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The rheological properties of emulsions are of considerable importance in a diverse range of scenarios. Here we describe a superposition of the effects of droplet elasticity and volume fraction on the dynamics of emulsions. The superposition is governed by physical interactions between droplets, and provides a new mechanism for modifying the flow behavior of emulsions, by controlling the elasticity of the dispersed phase. We investigate the properties of suspensions of emulsified wormlike micelles (WLM). Dense suspensions of the emulsified WLM droplets exhibit thermally responsive properties in which the viscoelastic moduli decrease by an order of magnitude over a temperature range of 0 • C to 25 • C. Surprisingly, the fragility (i.e. the volume-fraction dependence of the modulus) of the emulsions does not change with temperature. Instead, the emulsion modulus scales as a power-law with volume fraction with a constant exponent across all temperatures even as the droplet properties change from elastic to viscous. Nevertheless, the underlying droplet dynamics depend strongly on temperature. From stress relaxation experiments, we quantify droplet dynamics across the cage breaking time scale below which the droplets are locally caged by neighbors and above which the droplets escape their cages to fully relax. For elastic droplets and high volume fractions, droplets relax less stress through cage rattling and the terminal relaxations are slower than for viscous droplets and lower volume fractions. The cage rattling and cage breaking dynamics are highly correlated for variations in both temperature and emulsion concentration, suggesting that thermal and volume fraction effects represent independent parameters to control emulsion properties. arXiv:1912.03231v1 [cond-mat.soft]

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Dynamics and Rheology of Soft Colloidal Glasses

Cited by 31 publications

References 49 publications

Interfacial Particle Dynamics: One and Two Step Yielding in Colloidal Glass

Interfacial Particle Dynamics: One and Two Step Yielding in Colloidal Glass

Scaling Laws for Polymer Chains Grafted onto Nanoparticles

Correlation of droplet elasticity and volume fraction effects on emulsion dynamics

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