2020 年 48 巻 1 号 p. 15-25
Foams have a large number of applications in our daily life. Their stability depends on the thin liquid film, which consists of an aqueous phase bound by two air-water interfaces. During its processing, foam is exposed to a large deformation. Therefore, the study of the air-water interface under large amplitude oscillatory shear (LAOS) flow is highly relevant for foam stability. In this article, the LAOS behavior of the air-water interface was investigated. The interface was formed by 0.1 mol m−3 hexadecyltrimethylammonium bromide and 0.5% w/v silica nanoparticles. The LAOS study was performed by analyzing the intracycle stress waveforms and Lissajous-Bowditch curves. The Fourier transform rheology and Chebyshev polynomial approaches were used to describe the LAOS flow of the interface. The air-water interface exhibited intracycle strain-hardening and shear thickening behavior under the LAOS flow. However, at very large strain amplitude (i.e. 45%), the interface displayed intracycle shear thinning behavior.