Related Experiment Video
Updated: Jun 27, 2026

Glass-Based Devices to Generate Drops and Emulsions
Published on: April 5, 2022
Evaporation of sessile water/ethanol drops in a controlled environment
Chuanjun Liu1, Elmar Bonaccurso, Hans-Jürgen Butt
1Max Planck Institute for Polymer Research, Ackermannweg, 10, 55128 Mainz, Germany.
Abstract:
The evaporation of water/ethanol drops with different mixing ratios was investigated at controlled vapor pressure of water (relative humidity) and ethanol in the background gas. Therefore, a drop of about 1 microL was deposited on a hydrophobized silicon substrate at room temperature in a closed cell. With a microscope camera we monitored the contact angle, the volume and the contact radius of the drops as function of time. Pure water drops evaporated in constant contact angle mode. The evaporation rate of water decreased with increasing humidity. In mixed drops ethanol did not evaporate completely at first, but a fraction still remained in the drop until the end of evaporation. Depending on ethanol concentration in the drop and on relative humidity in the background gas, water vapor condensed at the beginning of the evaporation of mixed drops. Also, at a high vapor pressure of ethanol, ethanol condensed at the beginning of the evaporation. The presence of ethanol vapor accelerated the total evaporation time of water drops.
Related Concept Videos
Production of Alcohol
Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Distillation: Vapor–Liquid Equilibria
Acid-Catalyzed Dehydration of Alcohols to Alkenes
Vapor Pressure
Microbes in Beverage Production

