TY - GEN
T1 - Effects of structural topography on nanofluids droplet evaporation on multifarious superhydrophobic surfaces
AU - Xu, Wei
AU - Choi, Chang Hwan
PY - 2010
Y1 - 2010
N2 - In this paper, we experimentally studied the evaporation kinetics and wetting dynamics of nanofluid sessile droplets on microstructured superhydrophobic surfaces of a constant air fraction but different structural topographies including arrays of pillars, lines, and wells. The dissimilar superhydrophobic surface patterns were fabricated on a silicon substrate by photolithography and deep reactive ion etching (DRIE) followed by Teflon coating. The 0.01wt% suspensions of gold (Au) nanoparticles of 250 nm in diameter were tested as nanofluids. The change of contact angle, base diameter, height, volume, and evaporation rate of the evaporating nanofluid droplet was measured in a room condition by using a goniometer. The results show that the change of structural topographies, despite the same air fraction on the surface, make significant difference in the droplet profile evolution during sequential evaporation phases. Compared to pure water tested as control, the distinctive influence of nanoparticles was especially observed in the final pinning phase with the tested nanofluid condition. This paper demonstrates that the evaporation kinetics and wetting dynamics of liquid droplets are significantly affected by the structural topography and the presences of nanoparticulates, which should be considered in the design and applications of superhydrophobic surfaces for droplet-based heat and mass transfer systems.
AB - In this paper, we experimentally studied the evaporation kinetics and wetting dynamics of nanofluid sessile droplets on microstructured superhydrophobic surfaces of a constant air fraction but different structural topographies including arrays of pillars, lines, and wells. The dissimilar superhydrophobic surface patterns were fabricated on a silicon substrate by photolithography and deep reactive ion etching (DRIE) followed by Teflon coating. The 0.01wt% suspensions of gold (Au) nanoparticles of 250 nm in diameter were tested as nanofluids. The change of contact angle, base diameter, height, volume, and evaporation rate of the evaporating nanofluid droplet was measured in a room condition by using a goniometer. The results show that the change of structural topographies, despite the same air fraction on the surface, make significant difference in the droplet profile evolution during sequential evaporation phases. Compared to pure water tested as control, the distinctive influence of nanoparticles was especially observed in the final pinning phase with the tested nanofluid condition. This paper demonstrates that the evaporation kinetics and wetting dynamics of liquid droplets are significantly affected by the structural topography and the presences of nanoparticulates, which should be considered in the design and applications of superhydrophobic surfaces for droplet-based heat and mass transfer systems.
KW - Evaporation
KW - Nanofluids
KW - Superhydrophobic surface
UR - http://www.scopus.com/inward/record.url?scp=77954341684&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77954341684&partnerID=8YFLogxK
U2 - 10.1115/MNHMT2009-18263
DO - 10.1115/MNHMT2009-18263
M3 - Conference contribution
AN - SCOPUS:77954341684
SN - 9780791843895
T3 - Proceedings of the ASME Micro/Nanoscale Heat and Mass Transfer International Conference 2009, MNHMT2009
SP - 497
EP - 505
BT - Proceedings of the ASME Micro/Nanoscale Heat and Mass Transfer International Conference 2009, MNHMT2009
T2 - ASME 2009 Micro/Nanoscale Heat and Mass Transfer International Conference 2009, MNHMT2009
Y2 - 18 December 2009 through 21 December 2009
ER -