Molecular configurations in the droplet detachment process of a complex liquid

Sattler, Rainer; Kityk, A. V.; Wagner, Christian

doi:10.1103/physreve.75.051805

Cited by 8 publications

(6 citation statements)

References 29 publications

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“…Filaments retaining some fluid beads can easily be further extended by stretching out the thread to form daughter beads. The dry segments between the beads of a stretched filament provide molecular orientation 53 (as observed by the birefringence of the dried threads, see Fig. 6) and tensile strength to the spun biopolymer; however, the beads themselves may remain liquid-like for extended times.…”

Section: Fiber Formation and Capillary Instabilities At Large Deforma...mentioning

confidence: 99%

Microrheometry of sub-nanolitre biopolymer samples: non-Newtonian flow phenomena of carnivorous plant mucilage

et al. 2011

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Sundew plants (Drosera) capture insects using tiny drops of a viscoelastic fluid. These mucilage droplets are typically tens of micrometers in diameter, corresponding to fluid volumes in, or below, the nanoliter range. In contrast to other carnivorous plants, the physical principles and the role of rheology in the capturing mechanism are not yet fully understood. The rather simple chemical composition reported for the capturing fluid (a high molecular weight acidic polysaccharide composed of a D-glucurono-D-mannan backbone with alternating monosaccharide sidegroups) is in stark contrast to the compositional and structural complexity of other biological materials with strong extensional responses, including fibers, silks, or mucins. Here we show that the strategy used by the sundew plant combines the effects of high fluid viscosity, extensional viscoelasticity, capillary thinning and a liquid-to-solid transition driven by solvent mass transfer and aided by extensional strain-stiffening. More generally, we demonstrate how the rheological material functions of microscopic biopolymer samples in the sub-nanoliter range can be measured using an interferometry-based microrheometer for shear deformations and a capillary thinning microrheometer for extensional deformations.

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Section: Fiber Formation and Capillary Instabilities At Large Deforma...mentioning

confidence: 99%

Microrheometry of sub-nanolitre biopolymer samples: non-Newtonian flow phenomena of carnivorous plant mucilage

et al. 2011

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“…The rupture of Newtonian liquid columns can be modeled using self-similar solutions for the neck profile and power laws for the thinning of the neck [8]. Some complex fluids, however, exhibit an inhibition of such singular dynamics, which is replaced, in a sudden fashion, by single time dynamics represented by exponential thinning of the neck [6,[9][10][11][12]. Different classes of complex fluids have shown such a phenomenology: polymer solutions, corn starch solutions [13], and micellar phases of surfactant [14].…”

Section: Introductionmentioning

confidence: 99%

Stretching Polymers in Droplet-Pinch-Off Experiments

Ingremeau

Kellay

2013

Phys. Rev. X

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Droplet pinch off, which occurs when a drop of liquid detaches from a capillary, can be strongly modified in the presence of polymers, giving rise to long and slender filaments that thin slowly in time. However, little is known experimentally about the molecular conformations of the polymers in the filament itself. Since the thinning dynamics of these filaments can be used to extract macroscopic quantities of interest such as the elongational viscosity of polymer solutions, which is of importance in a variety of physical processes (electrospinning, spraying, or drag reduction), the link with the molecular scale dynamics would be an important step towards understanding the extensional properties of such solutions. We show here, experimentally, that the polymers are highly extended within this filament region and that the distribution of these extensions is stationary in time. We then determine the elongational viscosity from the full filament dynamics. Such a determination turns out to be consistent with the polymer extensions observed and also consistent with simple models of polymer elongational viscosities. The direct observation of stretched macromolecules within such suspended liquid filaments suggests that these filaments may be useful for preparing polymeric materials with specific anisotropy or for optical screening of biopolymers such as DNA.

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“…A powerful way to study the extensional behavior of complex fluids is the thinning and the ensuing rupture of liquid columns [2,[9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The rupture of Newtonian liquid cylinders can be modeled using self-similar solutions for the neck profile and power laws for the thinning of the neck [23].…”

mentioning

confidence: 99%

Depletion forces induce visco-elasto-capillary thinning of non-Brownian suspensions

Harich¹,

Deblais²,

Colin³

et al. 2016

EPL

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Droplet pinch-off, which occurs when a drop of liquid detaches from a capillary, can be strongly modified in the presence of complex fluids such as polymer solutions and suspensions giving rise to long and slender filaments that thin slowly in time. While for polymers, the molecular conformations of the molecules in the filament are responsible for such a behavior, in suspensions the mechanisms at play remain to be deciphered. Here we show, experimentally, that while liquid bridges of non-Brownian suspensions of moderate concentrations have a thinning behavior very close to that of the solvent, the addition of short-chain polymers inducing depletion attractions between the particles in the suspension changes the thinning dynamics and gives rise to exponential thinning in time. The characteristic time of this dynamics increases with polymer concentration and therefore the intensity of the depletion forces at play. The tunability of this dynamics may be important for injket and 3D printing applications where short rupture times are sought for or in other situations where drop formation has to be minimized or inhibited.

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Molecular configurations in the droplet detachment process of a complex liquid

Cited by 8 publications

References 29 publications

Microrheometry of sub-nanolitre biopolymer samples: non-Newtonian flow phenomena of carnivorous plant mucilage

Microrheometry of sub-nanolitre biopolymer samples: non-Newtonian flow phenomena of carnivorous plant mucilage

Stretching Polymers in Droplet-Pinch-Off Experiments

Depletion forces induce visco-elasto-capillary thinning of non-Brownian suspensions

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