A generalized model for the stability of polymer colloids

Jia, Zichen; Gauer, Cornelius; Wu, Hua; Morbidelli, Massimo; Chittofrati, A.; Apostolo, Marco

doi:10.1016/j.jcis.2006.06.011

Cited by 34 publications

(81 citation statements)

References 33 publications

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“…5). The theory is calculated assuming volume fraction 0.133, and provides a match with the data for values of F 0 well within the typical range of 10 6 to 5 × 10 8 Nm −2 (ref 19 ).…”

mentioning

confidence: 83%

Microscopic Origin of the Hofmeister Effect in Gelation Kinetics of Colloidal Silica

Linden

Conchuir

Spigone

et al. 2015

J. Phys. Chem. Lett.

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The gelation kinetics of silica nanoparticles is a central process in physical chemistry, yet not fully understood. Gelation times are measured to increase by over four orders of magnitude, simply changing the monovalent salt species from CsCl to LiCl. This striking effect has no microscopic explanation within current paradigms. The trend is consistent with the Hofmeister series, pointing to short-ranged solvation effects not included in the standard colloidal (DLVO) interaction potential. By implementing a simple form for short-range repulsion within a model that relates the gelation time-scale to the colloidal interaction forces, we are able to explain the many orders of magnitude difference in the gelation times at fixed salt concentration. The model allows to estimate the magnitude of the non-DLVO hydration forces, which dominate the interparticle interactions at the length-scale of the hydrated ion diameter. This opens the possibility of finely tuning the gelation time-scale of nanoparticles by just adjusting the background electrolyte species.

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“…5). The theory is calculated assuming volume fraction 0.133, and provides a match with the data for values of F 0 well within the typical range of 10 6 to 5 × 10 8 Nm −2 (ref 19 ).…”

mentioning

confidence: 83%

Microscopic Origin of the Hofmeister Effect in Gelation Kinetics of Colloidal Silica

Linden

Conchuir

Spigone

et al. 2015

J. Phys. Chem. Lett.

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“…For example, nonlinearity of the nanoscale forces can significantly modify the nano-micro hydrodynamic force balance thereby modifying the adhesion region. Our approach excludes spatial inhomogeneity arising through the material parameters, effects of catch behaviour (κ * s > 1.0), non-equilibrium binding effects, stochasticity and the discrete number of bonds (Zhu 2000), cellular viscoelasticity (needed to fully describe the cell rheology as mentioned by Dembo et al (1988)), electro-viscous drag on the spherical surfaces surrounded by ionic solution (Jia et al 2006) (which modifies the fluid velocity across the channel between the cells), as well as shearing forces large enough to tear the binding ligands from their anchoring surface (Varenberg and Gorb 2007). All these effects can lead to several non-trivial behaviours (including the possible absence of hysteresis in flow-phase transition) that deserves a full numerical investigation in the near future.…”

Section: Binder Kinetics At Steady Statementioning

confidence: 99%

“…Other examples of recent work includes developing probabilistic extensions of the Smoluchowski's multiplicative aggregation kernel in one (Odriozola et al 2007) and two dimensions (Moncho-Jordá et al 2001) and with kernels containing one scaling parameter to be fit to data. Jia et al (2006) developed a method for predicting critical coagulant concentration via deriving a kernel incorporating surface charge density and potential as a function of the electrolyte. Gilbert et al (2007) investigated and validated the forces and potentials for nanoparticles, whereas Bäbler and Morbidelli (2007) studied aggregation and fragmentation, but only driven by diffusion and shear flow.…”

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confidence: 99%

Surface deformation and shear flow in ligand mediated cell adhesion

Sircar

Roberts

2016

J. Math. Biol.

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We present a unified, multiscale model to study the attachment/detachment dynamics of two deforming, charged, near spherical cells, coated with binding ligands and subject to a slow, homogeneous shear flow in a viscous, ionic fluid medium. The binding ligands on the surface of the cells experience both attractive and repulsive forces in an ionic medium and exhibit finite resistance to rotation via bond tilting. The microscale drag forces and couples describing the fluid flow inside the small separation gap between the cells, are calculated using a combination of methods in lubrication theory and previously published numerical results. For a selected range of material and fluid parameters, a hysteretic transition of the sticking probability curves (i.e., the function [Formula: see text]) between the adhesion phase (when [Formula: see text]) and the fragmentation phase (when [Formula: see text]) is attributed to a nonlinear relation between the total nanoscale binding forces and the separation gap between the cells. We show that adhesion is favoured in highly ionic fluids, increased deformability of the cells, elastic binders and a higher fluid shear rate (until a critical threshold value of shear rate is reached). Within a selected range of critical shear rates, the continuation of the limit points (i.e., the turning points where the slope of [Formula: see text] changes sign) predict a bistable region, indicating an abrupt switching between the adhesion and the fragmentation regimes. Although, bistability in the adhesion-fragmentation phase diagram of two deformable, charged cells immersed in an ionic aqueous environment has been identified by some in vitro experiments, but until now, has not been quantified theoretically.

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“…Then, if an ionic surfactant is adsorbed on the particle surface, when coalescence occurs, the reduction in the total particle surface area changes the surfactant adsorption equilibrium, particularly, more surfactant molecules to be adsorbed on the particles, leading to increase in the colloidal stability. The consequence is that if one measures K 1,1 at different time, since the total surface area decreases with time, the K 1,1 value decreases with time as well for a coalescence system, while it remains constant for a noncoalescence one [6,33]. Therefore, to demonstrate the occurrence of coalescence under RLCA, we have added 0.7% (with respect to polymer mass) SDS to the given colloidal system and measured the rate constant for the doublet formation, K 1,1 , at three HCl concentrations, C HCl 00.33, 0.36, and 0.39 mol/L, respectively.…”

Section: Confirmation Of Coalescence Under Rlca From Doublet Formatiomentioning

confidence: 99%

“…Details about the technique require significant space to describe, thus not given here. Interested reader may refer to our previous publications [12,33]. It should be mentioned however that the technique is developed only for two extreme cases, non-coalescence and complete coalescence.…”

Section: Confirmation Of Coalescence Under Rlca From Doublet Formatiomentioning

confidence: 99%

Monitoring coalescence behavior of soft colloidal particles in water by small-angle light scattering

Wei

Xia

et al. 2012

Colloid Polym Sci

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The fractal dimension (D f ) of the clusters formed during the aggregation of colloidal systems reflects correctly the coalescence extent among the particles (Gauer et al., Macromolecules 42:9103, 2009). In this work, we propose to use the fast small-angle light scattering (SALS) technique to determine the D f value during the aggregation. It is found that in the diffusion-limited aggregation regime, the D f value can be correctly determined from both the power law regime of the average structure factor of the clusters and the scaling of the zero angle intensity versus the average radius of gyration. The obtained D f value is equal to that estimated from the technique proposed in the above work, based on dynamic light scattering (DLS). In the reactionlimited aggregation (RLCA) regime, due to contamination of small clusters and primary particles, the power law regime of the average structure factor cannot be properly defined for the D f estimation. However, the scaling of the zero angle intensity versus the average radius of gyration is still well defined, thus allowing one to estimate the D f value, i.e., the coalescence extent. Therefore, when the DLS-based technique cannot be applied in the RLCA regime, one can apply the SALS technique to monitor the coalescence extent. Applicability and reliability of the technique have been assessed by applying it to an acrylate copolymer colloid.

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A generalized model for the stability of polymer colloids

Cited by 34 publications

References 33 publications

Microscopic Origin of the Hofmeister Effect in Gelation Kinetics of Colloidal Silica

Microscopic Origin of the Hofmeister Effect in Gelation Kinetics of Colloidal Silica

Surface deformation and shear flow in ligand mediated cell adhesion

Monitoring coalescence behavior of soft colloidal particles in water by small-angle light scattering

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