Viscoelastic necking dynamics between attractive microgels

Chen, Shensheng; Pirhadi, Emad; Yong, Xin

doi:10.1016/j.jcis.2022.03.048

Cited by 9 publications

(9 citation statements)

References 41 publications

(17 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the current study, we have considered coalescence as arrested if _ g arrest o 0.5%(_ g DIwater ), where _ g is the shear rate (see the ESI † for shear rate calculations). The value of y arrest obtained from the experiments is 0.56 radians which is in agreement with the value obtained from eqn (14) i.e. 0.52 radians.…”

Section: Arrested Coalescencesupporting

confidence: 89%

“…A recent study by Chen et al 14 on polymers and gels showed that at later time scales, coalescence is slower than in Newtonian droplets. This conclusion was drawn based on stress relaxation behaviour observed in polymers using molecular dynamics simulation.…”

Section: Introductionmentioning

confidence: 98%

“…Each subclass has a different micro-structure composition leading to distinct behaviors. However, there are few recent studies on a special class of non-Newtonian fluids i.e., macromolecular fluids [10][11][12][13][14] that have highlighted the deviation from proposed Newtonian behaviour. But a generalized theoretical framework unifying various constitutive laws to probe the phenomenon in viscoelastic droplets remains an open question.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sub-Newtonian coalescence in polymeric fluids

2023

View full text Add to dashboard Cite

show abstract

Section: Arrested Coalescencesupporting

confidence: 89%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sub-Newtonian coalescence in polymeric fluids

2023

View full text Add to dashboard Cite

show abstract

“…The study also showed a universal scaling of R * ∼ t * 0.36 in the coalescence of polymeric droplets by nondimensionalizing the neck radius and time with and t c = Oh λ( c / c *) 1.2 , respectively, where ν o is the kinematic viscosity of the fluid, λ is the relaxation time, Oh is the Ohnesorge number, and c / c * is the concentration ratio. Recently, a numerical study by Chen et al showed the effect of polymer chain relaxation on the coalescence process. This study is in qualitative agreement with our previous results showing the deviation from Newtonian droplets’ coalescence.…”

Section: Introductionmentioning

confidence: 99%

Rheocoalescence: Relaxation Time through Coalescence of Droplets

2022

View full text Add to dashboard Cite

The dynamics of the pendant drop coalescing with a sessile drop to form a single daughter droplet is known to form a bridge. The bridge evolution begins with a point contact between the two drops leading to a liquid neck of size comparable to the diameter of the drops. To probe this phenomenon in polymeric fluids, we quantify the neck radius growth during coalescence using high-speed imaging. In this study, we unveil the existence of three regimes on the basis of concentration ratio c/c*, namely, inertioelastic c/c* < c e /c*, viscoelastic c e /c* < c/c* < 20, and elasticity dominated regimes c/c* > 20. Our results suggest that the neck radius growth with time (t) obeys a power-law behavior t b , such that the coefficient b has a steady value in inertioelastic and viscoelastic regimes, with a monotonic decrease in elasticity dominated regime. On the basis of this dependence of b on concentration ratios, we propose a new measurement technique, rheocoalescence, which possibly can predict the relaxation time of these fluids in the elasticity dominated regime. We also show a deviation from universality proposed in the literature for the elasticity dominated regime.

show abstract

“…However, at very high concentrations, Varma et al 33 showed a continuous decrease in power law exponent from 0.36. This is further supported qualitatively by a numerical study on polymers and microgels by Chen et al 34 Even a separate study for coalescence of polymeric droplet in sessile-sessile configuration by Varma et al 35 reported a decrease in exponent from 2/3 in the inertial regime to 1/2 in the viscoelastic regime. Correspondingly, a recent numerical study by Chen et al 36 investigating coalescence of nonelastic, shear-thinning fluid highlighted a strong relation between power law rheology and scaling exponent at the onset of coalescence.…”

Section: Introductionmentioning

confidence: 59%

Elasticity can affect droplet coalescence

2022

View full text Add to dashboard Cite

Coalescence of two droplets on a solid substrate is an interfacial phenomenon that imposes the challenges of capturing the complex contact line motion and energy interaction between the solid-liquid interface. Recent investigations on the coalescence of polymeric droplets on a solid substrate have reported strong disagreements; the heart of the issue is whether coalescence of polymeric drops is similar to that of Newtonian fluid and is independent of molecular relaxation, or whether the role of entanglement of polymeric chains leads to a transition kinetics different from that of Newtonian fluid. Via this article, we resolve the disagreements through a discussion on the effects of merging method on the dominant forces governing the coalescence process, i.e., inertia, dissipation, and relaxation. In this regard, two methods of merging have been identified, namely droplet spreading method (DSM) and volume filling method (VFM). Our study unveils that the coalescence dynamics of polymeric drops is not universal and in fact, is contingent of the method by which the coalescence is triggered. Additionally, we demonstrate the spatial features of the bridge at different time instants by a similarity analysis. We also theoretically obtain a universal bridge profile by employing the similarity parameter in a modified thin film lubrication equation for polymeric fluids.

show abstract

Viscoelastic necking dynamics between attractive microgels

Cited by 9 publications

References 41 publications

Sub-Newtonian coalescence in polymeric fluids

Sub-Newtonian coalescence in polymeric fluids

Rheocoalescence: Relaxation Time through Coalescence of Droplets

Elasticity can affect droplet coalescence

Contact Info

Product

Resources

About