TY - JOUR
T1 - Experimental study on spreading and evaporation of inkjet printed pico-liter droplet on a heated substrate
AU - Lim, Taewoong
AU - Han, Sewoon
AU - Chung, Jaewon
AU - Chung, Jin Taek
AU - Ko, Seunghwan
AU - Grigoropoulos, Costas P.
N1 - Funding Information:
Financial support to Korea University by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) under Grant No. KRF-2006-331-D00044 and by the Korea University Grant and to University of California, Berkeley, by the U.S. National Science Foundation under Grant CTS-0417563 is gratefully acknowledged.
PY - 2009/1/15
Y1 - 2009/1/15
N2 - In this work, the spreading and evaporation of 2-70 pL droplet (17-50 μm diameter) of water and ethylene glycol jetted by drop-on-demand piezo-driven jetting head on the heated substrate are studied. According to the experimental results, the interfacial oscillation phenomena of water droplet whose Ohnesorge number (Oh) is about 10-2 is similar to that in inviscid impact driven region, while that of ethylene glycol droplet (Oh ≈10-1) is similar to that in highly viscous impact driven region followed by capillary driven extra spreading. In addition, various time scales used for nano/micro-liter droplets agree well with the times for interfacial oscillation, viscous damping, extra wetting, and evaporation in pico-liter droplets. In the case of water droplet, the spreading processes end before the evaporation becomes significant. However, in the case of highly viscous ethylene glycol droplet, the extra wetting overlaps the evaporation at high temperature.
AB - In this work, the spreading and evaporation of 2-70 pL droplet (17-50 μm diameter) of water and ethylene glycol jetted by drop-on-demand piezo-driven jetting head on the heated substrate are studied. According to the experimental results, the interfacial oscillation phenomena of water droplet whose Ohnesorge number (Oh) is about 10-2 is similar to that in inviscid impact driven region, while that of ethylene glycol droplet (Oh ≈10-1) is similar to that in highly viscous impact driven region followed by capillary driven extra spreading. In addition, various time scales used for nano/micro-liter droplets agree well with the times for interfacial oscillation, viscous damping, extra wetting, and evaporation in pico-liter droplets. In the case of water droplet, the spreading processes end before the evaporation becomes significant. However, in the case of highly viscous ethylene glycol droplet, the extra wetting overlaps the evaporation at high temperature.
KW - Droplet
KW - Evaporation
KW - Flexible electronics
KW - Inkjet
KW - Spreading
UR - http://www.scopus.com/inward/record.url?scp=56949107628&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatmasstransfer.2008.05.028
DO - 10.1016/j.ijheatmasstransfer.2008.05.028
M3 - Article
AN - SCOPUS:56949107628
SN - 0017-9310
VL - 52
SP - 431
EP - 441
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
IS - 1-2
ER -