Binary sessile drops evaporation: IR and acoustic methods for alcohol concentration tracking at the interface and the surface
Résumé
Evaporation process of droplets of three pure liquids (water, 1-butanol, and ethanol) and four binary solutions (5 wt % 1-butanol water-based solution and 5, 25, and 50 wt % ethanol−water-based solutions) deposited on hydrophobic silicon substrate was studied under ambient condition. An optical technique combined by CCD and infrared cameras was used to investigate the dynamic evolution of contact angle, diameter, and volume of the droplets and the infrared thermal mapping on air/liquid interface. Meanwhile, an acoustic high-frequency echography technique was, for the first time, applied to track the alcohol concentration variation in a binary-solution droplet.