This paper deals with the potential of aggregates of surfactant and SiO₂ nanoparticles as foam stabilizers for practical applications. The effects of different chain lengths and concentrations of the cationic surfactant ${\mathrm{C}}_n$TAB on the performance of ${\mathrm{C}}_n$TAB–SiO₂ nanofluids are examined to gain a comprehensive understanding of their ability to stabilize foam. The results indicate enhanced foam stability in the presence of SiO₂ nanoparticles. These findings help to better understand foam stabilization and its potential in various industrial applications such as enhanced oil recovery and foam-based separation processes.

Today, naturally occurring foam constituents and surface-active proteins with intriguing structures and functions are being identified from a variety of biological and chemical sources. In this paper we studied the colloid chemical properties of high-molecular natural surfactants such as keratin hydrolyzate (1.5–15%), gelatin (0.1–1%), and egg albumin (0.1–1%) in a wide concentration range. The foaming ability and foam-stabilizing properties of mixtures of these proteins were established. The high stability of foams obtained from mixtures of surfactants can be explained by the formation of mixed structured layers from the surface-active associates, promoting the thickening of foam films. The ratio of polymer mixtures was optimized (keratin (15%)-albumin (1%) (1:1)) to produce high-quality foaming agents. The foam parameters such as surface tension, capillary pressure of the Plateau-Gibbs channels, radii of curvature, critical micelle concentration, and relative viscosity were defined. The high surface activity and foam stability corresponds to a pH close to the isoelectric state of the proteins. This occurs due to the conformational changes of macromolecules of the protein at the liquid-gas interface, forming particles of colloidal size.

The interaction between nanoparticles and cationic surfactants is an exciting and emerging field in interfacial science. This area of research holds significant promise, linking fundamental principles to practical applications in a variety of industries, including chemical processes, biomedical applications and the petroleum industry. This study explores the interaction between dodecyltrimethylammonium bromide (DoTAB) and silica (SiO₂) nanoparticles, investigating their influence on dynamic interfacial properties and foam characteristics. Through equilibrium and dynamic surface tension measurements, along with examining the dilational visco-elasticity behavior, this research reveals the complex surface behavior of DoTAB/SiO₂ mixtures compared to individual surfactant solutions. The foamability and stability experiments indicate that the addition of SiO₂ significantly improves the foam stability. Notably, stable foams are achieved at low SiO₂ concentrations, suggesting a cost-effective approach to enhancing the foam stability. This study identifies the optimal stability conditions for 12 mM DoTAB solutions, emphasizing the crucial role of the critical aggregation concentration region. These findings offer valuable insights for designing surfactant-nanoparticle formulations to enhance foam performance in various industrial applications.

Controlling the interfacial behavior is essential for understanding the efficiency of surfactant–nanoparticle systems in practice. In this study, we investigate how silica (SiO₂) nanoparticles alter the surface and interfacial properties of sodium dodecyl sulfate (SDS) solutions at water–air and water–hexane interfaces, as well as their impact on the formation and stabilization of foams. While the negatively charged SiO₂ nanoparticles alone exhibit negligible surface activity, their combination with SDS leads to the formation of composite interfacial layers with enhanced surface pressure and dilational viscoelasticity. The increase in interfacial pressure reflects a high surface concentration and denser packing of SDS–SiO₂ associates. Interfacial rheology measurements show that SDS–SiO₂ nanofluids form more elastic interfacial films compared to pure SDS, with a maximum dilational elasticity at intermediate surfactant concentrations. This indicates the formation of mechanically stronger interfacial layers capable of resisting deformation. Foam experiments demonstrate that silica nanoparticles significantly improve foam formation and foam stability. These improvements correlate with increased surface pressure and interfacial elasticity, demonstrating that foam stability is primarily determined by the formation of robust interfacial layers and not solely by a reduction in surface tension. Overall, this study demonstrates how the presence of silica nanoparticles can affect the adsorption of SDS via hydrophobic interaction, leading to the formation of stronger interfacial films, improved foam stability, and expanded potential for applications in industrial processes, such as foam flooding based on nanoparticle/surfactant solutions to enhance oil–gas recovery.

This study focuses on the properties of the nonionic surfactant Genapol and the cationic surfactant cetylpyridinium chloride (CPC) to develop a composite detergent with bactericidal activity. Research includes studying the properties of CPC and Genapol solutions, creating composite mixtures with different concentration ratios and assessing the bactericidal effectiveness of the resulting detergents. The main foaming agents CPC and Genapol were used without purification, which emphasizes their high biodegradability. Various tests, including surface tension measurements, contact angle evaluation and pH measurements, were carried out at room temperature to evaluate the properties of surfactants and surfactant mixtures. The results show that CPC exhibits foaming, emulsifying and bactericidal properties due to its high surface activity and adsorption capacity. Genapol has the advantages of high surface activity at different pH levels, excellent foaming and emulsifying properties. The combination of these surfactants in a complex detergent creates a universal cleaner with antibacterial properties independent of pH and environmental harshness. The bactericidal effect of solutions of CPC Genapol mixtures was also determined. The results show that the composite solution exhibits a noticeable bactericidal effect with zones of growth inhibition ranging from 13.5±0.5 mm to 17±0.1 mm. The greatest antibacterial activity was observed against Micobacterium citreum and Bacillus subtilis. Sarcina flava and Staphylococcus aureus showed similar growth inhibition results.