Why do lamellar phase forming surfactants have better foaming properties than micelle forming surfactants ? What is the relationship of the interfacial and the foaming properties ?
Reference: Interfacial and foaming properties of some food grade low molecular weight surfactants. J.-B. Bezelgues; S. Serieyeb; L. Crosset-Perrotin; M.E. Leser; Colloids and Surfaces A: Physicochem. Eng. Aspects 331 (2008) 56–62.
The objective of the present work is to understand the relationship between the interfacial tension and the foaming properties of two different surfactant groups: lamellar phase forming surfactants and micelle forming surfactants. At the scale of the interface, drop tensiometry measurements and gas permeability experiments using the diminishing bubble technique are used. Lamellar phase forming surfactants show interesting interfacial properties: low equilibrium surface tension and high surface dilatational moduli suggesting exceptional foaming properties.
This has been conformed thanks to experiments at the scale of the foam using a FOAMSCAN™ foam analyzer and the Cell Size Analysis software where foams produced with lamellar phase forming surfactants give the most stable foams having the smallest bubbles.
TECLIS product: FOAMSCAN™ foam analyzer, Cell Size Analysis software
Key words: Lamellar phase/micelle forming surfactants, gas permeability, interfacial rheology , foamability, foam stability , bubble distribution
How does coalescence impact the
rheological properties of polyglycerol
ester (PGE) bubbles ?
Reference: Interfacial aspects of the stability of polyglycerol ester covered bubbles against coalescence C. Curschellas; D. Z. Gunes; H. Deyber; B. Watzke; E. Windhaba; H. J. Limbach; Soft Matter, 2012, 8, 11620.
Coalescence is one of the major destabilizing processes in liquid foams; it is thus important to have a clear understanding of this aging mechanism. In this work, interfaces covered with polyglycerol ester (PGE) molecules, a non-ionic surfactant, are investigated. The influence of large deformations, that can either induce the coalescence of two bubbles or be observed afterwards during the relaxation phase, on the interfacial properties of PGE covered interfaces is studied through interfacial shear rheology experiments, single bubble experiments using a pendant drop tensiometer with bulk phase exchange and finally the shape relaxation following the coalescence of two isolated bubbles was recorded. The recovery from the effect of large shear deformations was shown to be rapid until a certain limit only, with the full recovery requiring timescales of hours. While a temporary increase in the elastic dilatational modulus was observed as a result of compression.
TECLIS product: TRACKER™ automatic drop tensiometer with Phase exchange module
Key words: Non-ionic surfactant, bubble coalescence, interfacial shear and dilatational rheology, equilibrium surface/interfacial tension, 2D foam
How do proteins interact with different types of surfactant and what are the effects on the interfacial properties ?
Reference: Interaction Mechanism of Different Surfactants with Casein: A Perspective on Bulk and Interfacial Phase Behavior; Q. Tian; L. Lai; Z. Zhou; P. Mei; Q. Lu; Y. Wang; D. Xiang; Y. Liu; : J. Agric. Food Chem. 2019, 67, 6336−6349.
Protein/surfactant interactions are of major interest in the food industry. In this paper, the interactions between casein and different surfactants : Gemini surfactants (BQAS and SGS), biosurfactants (RL and SL) and SDS are studied. ). It has been found that the hydrophobicity of casein molecules increases when BQAS and SDS were added due to the formation of complexes. Dynamic interfacial tension measurements performed with a drop tensiometer (TRACKER™ by TECLIS) showed indeed that these complexes have a higher surface activity compared to that of pure casein. Additional interfacial dilational viscoelasticity experiments consisting in tracking surface tension variation during the oscillation of a bubble (performed with the TRACKER™) proved that the interface was covered by complexes in the case of BQAS/SGS and casein mixtures while competitive adsorption between casein and SGS, RL and SL has been demonstrated.
TECLIS product: TRACKER™ automatic drop tensiometer
Key words: Casein, Gemini surfactant, biosurfactant, surface and interfacial properties, equilibrium surface tension, dynamic interfacial tension, interfacial dilational viscoelasticity, UV-vis, DLS