Influence of nanoparticles on rheological properties and foam properties of mixed solutions of fluorocarbon and hydrocarbon surfactants

Mixed dispersions of silica nanoparticles (NPs), nonionic hydrocarbon surfactant (APG0810), and fluorocarbon surfactant (FS-50) in water were prepared. The molecular interactions, rheological properties, and foam properties of the mixed dispersions were experimentally investigated. The enhancement mechanism of the NPs on the foam stability of the mixture of APG0810/FS-50 was analyzed. Results showed that the NPs strongly influenced the rheological and foam properties of the mixed solutions. The viscosity of the APG0810/FS-50/NPs dispersions varied linearly with the shear rate, and the viscoelastic modulus of the dispersions increased with increasing NP concentration. With the increase of NP concentration, the foam stability was enhanced but the foaming properties was weakened. Foam drainage, foam coarsening, and foam mechanical strength were apparently enhanced because of the aggregation of a large amount of NPs in the plateau borders. This research gives theoretical guidance for the application of NPs in fire extinguishing agent.