Effect of substrate temperature on pattern formation of nanoparticles from volatile drops.
This study investigates pattern formation during evaporation of water-based nanofluid sessile droplets placed on a smooth silicon surface at various temperatures. An infrared thermography technique was employed to observe the temperature distribution along the air-liquid interface of evaporating droplets. In addition, an optical interferometry technique is used to quantify and characterize the deposited patterns. Depending on the substrate temperature, three distinctive deposition patterns are observed: a nearly uniform coverage pattern, a "dual-ring" pattern, and multiple rings corresponding to "stick-slip" pattern. At all substrate temperatures, the internal flow within the drop builds a ringlike cluster of the solute on the top region of drying droplets, which is found essential for the formation of the secondary ring deposition onto the substrate for the deposits with the "dual-ring" pattern. The size of the secondary ring is found to be dependent on the substrate temperature. For the deposits with the rather uniform coverage pattern, the ringlike cluster of the solute does not deposit as a distinct secondary ring; instead, it is deformed by the contact line depinning. In the case of the "stick-slip" pattern, the internal flow behavior is complex and found to be vigorous with rapid circulating flow which appears near the edge of the drop.
†TEMPO Laboratory, University of Valenciennes, Valenciennes 59313, France.|‡The VEDECOM Institute, 77 Rue des Chantiers, Versailles 78000, France.
Maryam
M
Parsa
†TEMPO Laboratory, University of Valenciennes, Valenciennes 59313, France.
Souad
S
Harmand
§School of Engineering, Kings Buildings, University of Edinburgh, Edinburgh EH9 3JL, United Kingdom.|∥International Institute for Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
Khellil
K
Sefiane
†TEMPO Laboratory, University of Valenciennes, Valenciennes 59313, France.
Maxence
M
Bigerelle
†TEMPO Laboratory, University of Valenciennes, Valenciennes 59313, France.
Raphaël
R
Deltombe
D053758:Nanoparticles / Q000737:chemistry*; D013696:Temperature; D014835:Volatilization