Oscillation of interfacial properties in liquid systems: assessment of harmonic distortion

Loglio, G.; Pandolfini, P.; Miller, R.; Makievski, A. V.; Krägel, J.; Ravera, Francesca

doi:10.1039/b314592c

Cited by 29 publications

(23 citation statements)

References 5 publications

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“…In addition to the analysis described in this paper, the observed surface oscillation response could be expanded in a Fourier series 16,17 or a series of Chebyshev polynomials. 15 However, we believe that in this situation the graphical presentation leads to more insight.…”

Section: Methodsmentioning

confidence: 99%

Non-linear surface dilatational rheology as a tool for understanding microstructures of air/water interfaces stabilized by oligofructose fatty acid esters

et al. 2013

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Section: Methodsmentioning

confidence: 99%

Non-linear surface dilatational rheology as a tool for understanding microstructures of air/water interfaces stabilized by oligofructose fatty acid esters

et al. 2013

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“…In the literature, the THD-parameter was used to quantify the inaccuracies of dosing system and disturbances [35,36]. We show that THD is significantly influenced by a, but is not influenced by f. Generally, a nonlinearity appears at higher a. Saulnier et al [32] found that nonlinear phenomena appear for a DPPC monolayer when a > 10%.…”

Section: Dependence Of η and ε On Oscillation Frequency And Amplitudementioning

confidence: 97%

“…Inaccuracies of dosing and disturbances were quantified by the total harmonic distortion (THD) [35,36], expressed as a percentage of a 1 :…”

Section: Surface Rheology Measurementsmentioning

confidence: 99%

Surface rheology of monolayers of phospholipids and cholesterol measured with axisymmetric drop shape analysis

Vrânceanu

Winkler

Nirschl

et al. 2007

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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Surface rheology of monolayers of a saturated phospholipid (dipalmitoylphosphatidylcholine, DPPC), an unsaturated phospholipid (dioleoylphosphatidylcholine, DOPC) and cholesterol is studied with axisymmetric drop shape analysis at the argon/water interface. Measurement techniques for lipids are described in detail. Profile analysis tensiometry (PAT) is used to determine the film pressure Π, surface elasticity and surface dilational viscosity of monolayers upon sinusoidal oscillations of the drop surface for various amplitudes a and frequencies f to assess their dependence on these dynamic parameters. It is shown that surface dilational viscosity strongly depends on the frequency and decreases by a factor 2-5 with increasing f in the considered range. Dilational viscosity is higher the more the monolayer approaches a relaxed state. Thus, the molecular interactions are stronger in the relaxed than in the stressed state. Surface elasticity is much less dependent on dynamic conditions. For DPPC a minimum of the dynamic surface elasticity is found for f = 12.5 mHz (at Π = 17.5 mN m −1 ) which coincides well with the relaxation frequencies measured in stress relaxation experiments. The dynamic surface elasticity of DPPC exhibits a plateau in the range 13.5 mN m −1 ≤ Π ≤ 27 mN m −1 in good coincidence with the phase boundaries of the coexistence region of micron-sized liquid crystalline domains surrounded by a fluid monolayer phase. In equilibrium measurements (Π/A-isotherms) a plateau of the film pressure is seen at the lower bound and a break at the upper bound of the coexistence region. Film pressure/area isotherms produced by PAT and a Langmuir film balance closely coincide as is shown in a comparison to literature values. However, the surface elasticities measured dynamically with oscillating surfaces widely deviate from those derived from isotherms in the case of DPPC and cholesterol, whereas for DOPC very good agreement can be found.

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“…The excitation-response behavior of the drop needs to be in linearity for a harmonic behavior. If the relationship is non-linear, the system shows non-harmonic distortion which can result in severe a calculation mistake [30]. The harmonic distortion was observed.…”

Section: Dilatational Rheologymentioning

confidence: 99%

“…So far, no study systematically analyzed the applicability of the interfacial methods at an increased concentration far beyond the common concentrations of 1-2%. However, the suitability of the measurement equipment as well as the model-based calculations can be verified via specific indicators for accuracy of measurement and calculation [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Interfacial Properties of β-Lactoglobulin at the Oil/Water Interface: Influence of Starch Conversion Products with Varying Dextrose Equivalents

et al. 2020

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In spray dried emulsions, frequently milk proteins are used as interfacial active components and starch conversion products are added as matrix material at high concentrations. To characterize interfacial properties at the oil/water interface by commonly applied methods, low protein, and carbohydrate concentrations from 1 to 2% are usually analyzed. The impact of a higher concentration of starch conversion products was not investigated so far. Therefore, the formation and rheological properties of β-lactoglobulin (β-LG) stabilized films at the oil/water interface were investigated via short and long-time adsorption behavior using pendant drop tensiometry as well as dilatational and interfacial shear rheology. Suitability of the applied methods to the chosen samples with higher concentrations >1–2% was verified by calculation of selected key numbers like capillary number and by detailed reviewing of the results which is summarized further on as key indicators. It is hypothesized, that the increase in concentration via presence of starch conversion products will delay interfacial stabilization as a result of increased bulk viscosity with decreasing degree of degradation (dextrose equivalent) of the starch. Furthermore, this increase in concentration leads to more stable interfacial films due to thermodynamic incompatibility effects between protein and starch conversion products which results in increases of local protein concentration. Key indicators proved a general suitability of applied methods for the evaluation of the investigated samples. Moreover, results showed an increase in interfacial film stability and elastic properties alongside a decreased interfacial tension if starch conversion products were present in a high concentration.

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Oscillation of interfacial properties in liquid systems: assessment of harmonic distortion

Cited by 29 publications

References 5 publications

Non-linear surface dilatational rheology as a tool for understanding microstructures of air/water interfaces stabilized by oligofructose fatty acid esters

Non-linear surface dilatational rheology as a tool for understanding microstructures of air/water interfaces stabilized by oligofructose fatty acid esters

Surface rheology of monolayers of phospholipids and cholesterol measured with axisymmetric drop shape analysis

Interfacial Properties of β-Lactoglobulin at the Oil/Water Interface: Influence of Starch Conversion Products with Varying Dextrose Equivalents

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