Evaporation of Ethanol-Water Mixture Drop on Horizontal Substrate

Abstract

This study investigates the evaporation of sessile drop comprising ethanol and water mixture on horizontal poly methyl methacrylate surface. The contact angle (θ) and contact radius (R) of ethanol-water mixture drop are recorded with time, considering the impacts of presence of ethanol. With excess ethanol, the drop evaporation is principally controlled by a phase in which both the contact angle and contact radius are falling. A diffusional model assuming linear relation between contact radius and time is proposed as θ = eR ⁻³ + cR ⁻¹, where e and c denote fitting coefficients. This model correlates with the experimental data.