Comment pubs.acs.org/Langmuir
Reply to Comment on Increased Evaporation Kinetics of Sessile Droplets by Using Nanoparticles
W
e write in response to the comments on our recent paper1 concerning the analytical model of the combined pinned−depinning evaporation lifetime of a sessile droplet. We thank Stauber et al.,2 who confirmed that there is no real contradiction in our work. We take this opportunity to discuss further our analytical model presented in ref 1. Specifically, the normalized droplet lifetime, τ, of the combined evaporation mode is a sum of two positive functions of the initial contact angle, θ0, and the transition contact angle, θ*. We agree that τ is bounded by ineq 5 as described in ref 1 only if θ0 < 148°. Indeed, our Figure 2 presented in ref 1 shows that when θ0 < 148°, τ is shorter than the lifetime of the receding mode but longer than the lifetime of the pinned mode and that when θ0 > 148°, the upper and lower limits of τ are inverse and the two signs of our ineq 5 should be converse. We did also emphasize that the dependence of droplet lifetime on the initial contact angle would not be very strong for these evaporation modes with large θ0 such as in the case of evaporation on superhydrophobic surfaces.1,3
Tuan A. H. Nguyen Anh V. Nguyen*
■ ■
School of Chemical Engineering, The University of Queensland, Brisbane, Queensland QLD 4072, Australia
ACKNOWLEDGMENTS We sincerely thank Dr. Bruce Armitage, Senior Editor of Langmuir, for his encouragement in writing this reply. REFERENCES
(1) Nguyen, T. A. H.; Nguyen, A. V. Increased evaporation kinetics of sessile droplets by using nanoparticles. Langmuir 2012, 28, 16725− 16728. (2) Stauber, J. M.; Wilson, S. K.; Duffy, B. R.; Sefiane, K. Comment on Increased evaporation kinetics of sessile droplet by using nanoparticles.Langmuir 2013, doi: 10.1012/la401717c. (3) Nguyen, T. A. H.; Nguyen, A. V. On the lifetime of evaporating sessile droplets. Langmuir 2012, 28, 1924−1930.
Published: September 19, 2013 © 2013 American Chemical Society
12330
dx.doi.org/10.1021/la403151k | Langmuir 2013, 29, 12330−12330
