The effect of binding of an oligomeric cationic fluorooxetane surfactant on the interfacial properties of adsorbed gelatin-fluorooxetane complexes has been studied using dynamic surface tension and dilational rheological measurements. Adsorption kinetics of gelatin-fluorooxetane complexes are reminiscent of a mixed (barrier/diffusion limited) process, while the dilational rheological properties of the interface exhibit a strong dependence on surfactant concentration. At low surfactant concentrations, dilational surface moduli as well as phase angles are relatively insensitive to the presence of the fluorooxetane. However, at the critical aggregation concentration of the polymer-surfactant system, there is a sharp increase in the complex modulus. Further increase in the fluorooxetane concentration does not significantly affect the complex modulus. The phase angle, however, does increase with increasing fluorooxetane concentration due to the transport of bound fluorooxetane from the subsurface to the solution-air interface. These results indicate that, at fluorooxetane concentrations exceeding the critical aggregation concentration, the polymer-surfactant complexes adsorb to form cross-linked multilayers at the solution-air interface.
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Food Chem
December 2024
State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China.
The intricate interactions between stevioside (STE) and milk protein (mixtures of whey protein isolate and sodium caseinate, WPI/SC) as well as interfacial stabilization mechanisms were investigated. At the molecular scale, it was observed that the incorporation of the steviol hydrophobic skeleton enhanced the surface hydrophobicity of WPI/SC (from 1560.73 to 2175.
View Article and Find Full Text PDFSoft Matter
November 2024
Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
We present experiments involving oscillating droplets in aqueous cyclodextrin-surfactant solutions. In these experiments, α-cyclodextrin (αCD) and anionic surfactants exhibit remarkable viscoelasticity at the liquid/air interface, with dilatational modulus varying across orders of magnitude. This rheological response depends on the concentrations of different complexes in the solution, particularly of the 2 : 1 inclusion complexes formed by two αCD molecules (αCD), and one surfactant (S).
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Laboratory of Biobased Chemistry and Technology, Wageningen University, Bornse Weilanden 9, 6708WG Wageningen, The Netherlands. Electronic address:
Hypothesis: Oilseeds use triacylglycerides as main energy source, and pack them into highly stable droplets (oleosomes) to facilitate the triacylglycerides' long-term storage in the aqueous cytosol. To prevent the coalescence of oleosomes, they are stabilized by a phospholipid monolayer and unique surfactant-shaped proteins, called oleosins. In this study, we use state-of-the-art interfacial techniques to reveal the function of each component at the oleosome interface.
View Article and Find Full Text PDFNat Protoc
September 2024
Institute of Energy, Peking University, Beijing, P.R. China.
J Colloid Interface Sci
January 2025
Department of Chemical Engineering, The City College of New York, New York, NY, 10031, USA. Electronic address:
Hypothesis: Lanthanide Binding Tag (LBT) peptides that coordinate selectively with lanthanide ions can be used to replace the energy intensive processes used for the separation of rare earth elements (REEs). These surface-active biomolecules, once selectively complexed with the trivalent REE cations, can adsorb to air/aqueous interfaces of bubbles for foam-based REEs recovery. Glutaraldehyde, an organic compound that is a homobifunctional crosslinker for proteins and peptides, can be used to enhance the adsorption and interfacial stabilization of lanthanide-bound peptides films.
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