Oscillatory rheology of aqueous foams: surfactant, liquid fraction, experimental protocol and aging effects

Marze, Sébastien; Guillermic, Reine‐Marie; Saint‐Jalmes, Arnaud

doi:10.1039/b817543h

Cited by 73 publications

(55 citation statements)

References 36 publications

(96 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…the foam yields, when the maximum in G 00 or the crossover of G 0 and G 00 is reached as also reported in earlier studies. 31,32 Similar behavior has been reported for whey protein isolate foams 7 and was explained as follows: in several studies BLG has been found to form aggregates in thin liquid lms that are able to "glue" the surfaces together. 33,34 The simultaneous decrease of both moduli was interpreted as a gradual destruction of the intralamellar protein networks before the bubbles start to move past each other.…”

Section: Foam Preparation and Measurementssupporting

confidence: 73%

“…30 The foams with lower gas volume fractions did not show this maximum which was explained by the occurrence of plastic deformation prior to yielding. Other studies 31,32 consider the point, where dissipation is maximal, as the transition point from elastic to viscous behavior, hence as the yield point. The simultaneous decrease of G 0 and G 00 for salt concentrations up to 30 mM indicates a gradual structure break down.…”

Section: Foam Preparation and Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

Relating foam and interfacial rheological properties of β-lactoglobulin solutions

Lexis

Willenbacher

2014

Soft Matter

View full text Add to dashboard Cite

We have determined bulk rheology of b-lactoglobulin (BLG) foams and surface viscoelasticity of corresponding protein solutions by varying pH as well as type, valency and concentration of the added salt in a wide range. Foam rheology was characterized by the storage modulus G 0 , the apparent yield stress s y , and the critical strain g c,foam defining the cessation of the linear viscoelastic response. These quantities were determined at gas volume fractions f between 82% and 96%. Surface viscoelasticity was characterized in shear and dilation, corresponding shear and dilational moduli G 0 i , E 0 as well as the critical stress s c,surface and strain g c,surface marking the onset of non-linear response in oscillatory surface shear experiments were determined at fixed frequency. Beyond the widely accepted assumption that G 0 and s y are solely determined by the Laplace pressure within the droplets and the gas volume fraction we have found that both quantities strongly depend on corresponding interfacial properties. G 0 increases linearly with G 0 i and even stronger with E 0 , s y varies proportional to s c,surface and g c,foam scales linearly with g c,surface . Furthermore, deviations from these simple scaling laws with significantly higher reduced G 0 and s y values are observed only for foams at pH 5 and when a trivalent salt was added. Then also the dependence of these quantities on f is unusually weak and we attribute these findings to protein aggregation and structure formation across the lamellae than the dominating bulk rheology.

show abstract

Section: Foam Preparation and Measurementssupporting

confidence: 73%

Section: Foam Preparation and Measurementsmentioning

confidence: 99%

Relating foam and interfacial rheological properties of β-lactoglobulin solutions

Lexis

Willenbacher

2014

Soft Matter

View full text Add to dashboard Cite

show abstract

“…Apart from this, the SRFS procedure supplies a unified picture of the slow relaxation dynamics [15] in a wide range of soft materials and is of intrinsic interest. Similar results have been confirmed in a micelle-forming triblock copolymer [16], aqueous foams [17], and dough mixed with gluten [18]. However, the results in Wyss, et.al.…”

Section: Introductionsupporting

confidence: 71%

Strain-rate frequency superposition in large-amplitude oscillatory shear

2010

View full text Add to dashboard Cite

In a recent work, Wyss, et.al. [Phys. Rev. Lett., 98, 238303 (2007)] have noted a property of 'soft solids' under oscillatory shear, the so-called strain-rate frequency superposition (SRFS). We extend this study to the case of soft solids under large-amplitude oscillatory shear (LAOS). We show results from LAOS studies in a monodisperse hydrogel suspension, an aqueous gel, and a biopolymer suspension, and show that constant strain-rate frequency sweep measurements with soft solids can be superimposed onto master curves for higher harmonic moduli, with the same shift factors as for the linear viscoelastic moduli. We show that the behavior of higher harmonic moduli at low frequencies in constant strain-rate frequency sweep measurements is similar to that at large strain amplitudes in strain-amplitude sweep tests. We show surface plots of the harmonic moduli and the energy dissipation rate per unit volume in LAOS for soft solids, and show experimentally that the energy dissipated per unit volume depends on the first harmonic loss modulus alone, in both the linear and the nonlinear viscoelastic regime.

show abstract

“…In practice, σ y is often determined by measuring the stress response to an oscillatory strain of increasing amplitude. Except for cases where shear banding occurs, the different approaches for measuring a yield stress generally give consistent results [41][42][43]. Typical results for foams and emulsions obtained using the oscillatory technique, expressed in terms of a strain amplitude ε 0 dependent complex shear modulus G * (ε 0 ) = G′(ε 0 ) + iG″(ε 0 ), are shown in Fig.…”

Section: Yieldingmentioning

confidence: 85%