关键词: 超疏水, 表面活性剂, 聚合物, 黏度, 沉积

Abstract:

High-speed cameras were used to capture the impact of deionized water droplets, three relative molecular masses of polyethylene oxide (PEO) droplets, bis(2-ethylhexyl)sulfosuccinate (AOT) droplets of surfactant and a combination of two additives on the surface of lotus leaves. Comparative analysis of the deposition characteristics of droplets with different characteristics on the leaf surface were studied by comparative analysis. The experimental results showed that PEO additives could significantly inhibit droplet rebound and increase droplet residence time on leaf surface, and prevent outward emission of satellite droplets. The inhibition effect of high relative molecular mass PEO (5×10⁵, 2×10⁶) was more obvious, but it would reduce the spreading area of droplets on the leaf surface. Low mass fraction (0.005%, 0.02%) of AOT additives could increased the spreading area of droplets on the leaf surface, reduced the droplet pop-up height and wet the local impact area, but at high impact velocities (v>1.66m/s), the droplets would break multiple satellite droplets and eject from the leaf surface during contraction. At increasing the AOT mass fraction at 0.1%, the droplets were able to wet the leaf surface at the spreading stage and spread to a larger area in a short time. A mixture of droplets using both PEO and AOT additives combining the advantages of polymers and surfactants, was capable of forming filaments that draw drew droplets in the localized wetted areas, enhancing the effective deposition of droplets on the leaf surface. By compiling and analyzing the experimental data, it was found that droplets were more likely to be deposited on the leaf surface by increasing the Weber number (We) while decreasing the Reynolds number (Re).

Key words: superhydrophobic, surfactants, polymers, viscosity, deposition