TY - JOUR
T1 - Droplet Evaporation Dynamics of Low Surface Tension Fluids Using the Steady Method
AU - Günay, A Alperen
AU - Gnadt, Marisa
AU - Sett, Soumyadip
AU - Vahabi, Hamed
AU - Kota, Arun K
AU - Miljkovic, Nenad
N1 - Funding Information:
The authors gratefully acknowledge the funding support from the National Science Foundation under award no. 1554249. N.M. gratefully acknowledges the funding support from the International Institute for Carbon Neutral Energy Research (WPI–I2CNER), sponsored by the Japanese Ministry of Education, Culture, Sports, Science and Technology. A.K.K. gratefully acknowledges the support from the American Chemical Society Petroleum Research Fund and from the National Science Foundation under award 1751628.
PY - 2020/11/24
Y1 - 2020/11/24
N2 - Droplet evaporation governs many heat- and mass-transfer processes germane in nature and industry. In the past 3 centuries, transient techniques have been developed to characterize the evaporation of sessile droplets. These methods have difficulty in reconciling transient effects induced by the droplet shape and size changes during evaporation. Furthermore, investigation of evaporation of microdroplets residing on wetting substrates, or fluids having low surface tensions (<30 mN/m), is difficult to perform using established approaches. Here, we use the steady method to study the microdroplet evaporation dynamics of low surface tension liquids. We start by employing the steady method to benchmark with water droplets having base radii (20 ≤ R
b ≤ 260 μm), apparent advancing contact angle (45° ≤ θ
a,app ≤ 162°), surface temperature (30 < T
s < 60 °C), and relative humidity (40% < ϕ < 60%). Following validation, evaporation of ethanol (≈22 mN/m), hexane (≈18 mN/m), and dodecane (≈25 mN/m) were studied for 90 ≤ R
b ≤ 400 μm and 10 < T
s < 25 °C. We elucidate the mechanisms governing the observed behavior using heat and mass transport scaling analysis during evaporation, demonstrating our steady technique to be particularly advantageous for microdroplets, where Marangoni and buoyant forces are negligible. Our work not only elucidates the droplet evaporation mechanisms of low surface tension liquids but also demonstrates the steady method as a means to study phase change processes.
AB - Droplet evaporation governs many heat- and mass-transfer processes germane in nature and industry. In the past 3 centuries, transient techniques have been developed to characterize the evaporation of sessile droplets. These methods have difficulty in reconciling transient effects induced by the droplet shape and size changes during evaporation. Furthermore, investigation of evaporation of microdroplets residing on wetting substrates, or fluids having low surface tensions (<30 mN/m), is difficult to perform using established approaches. Here, we use the steady method to study the microdroplet evaporation dynamics of low surface tension liquids. We start by employing the steady method to benchmark with water droplets having base radii (20 ≤ R
b ≤ 260 μm), apparent advancing contact angle (45° ≤ θ
a,app ≤ 162°), surface temperature (30 < T
s < 60 °C), and relative humidity (40% < ϕ < 60%). Following validation, evaporation of ethanol (≈22 mN/m), hexane (≈18 mN/m), and dodecane (≈25 mN/m) were studied for 90 ≤ R
b ≤ 400 μm and 10 < T
s < 25 °C. We elucidate the mechanisms governing the observed behavior using heat and mass transport scaling analysis during evaporation, demonstrating our steady technique to be particularly advantageous for microdroplets, where Marangoni and buoyant forces are negligible. Our work not only elucidates the droplet evaporation mechanisms of low surface tension liquids but also demonstrates the steady method as a means to study phase change processes.
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U2 - 10.1021/acs.langmuir.0c02272
DO - 10.1021/acs.langmuir.0c02272
M3 - Article
C2 - 33167611
VL - 36
SP - 13860
EP - 13871
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 46
ER -