TY - JOUR
T1 - Macrotextures-enabled self-propelling of large condensate droplets
AU - Cheng, Yaqi
AU - Liu, Yuanbo
AU - Ye, Xuan
AU - Liu, Minjie
AU - Du, Bingang
AU - Jin, Yuankai
AU - Wen, Rongfu
AU - Lan, Zhong
AU - Wang, Zuankai
AU - Ma, Xuehu
N1 - Funding Information:
The authors gratefully acknowledge funding support from the National Natural Science Foundation of China (No. 51836002 ) and the Innovation and Technology Fund of Hong Kong (No. 9440175 ).
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/1
Y1 - 2021/2/1
N2 - On superhydrophobic surfaces, small condensate droplets exhibit a preferred self-propelled jumping by a coalescence-induced energy release, but large condensate droplets in several millimeters remain immobile. The accumulation of large condensate droplets leads to many problems such as shielding the growth of small droplets and increasing the thermal resistance of condensate. In this work, we present a largely unexplored strategy for enhancing the self-removal of large condensate droplets by the rational design of the millimetric macro-textured groove arrays (MGAs). In the condensation process, such macrotextures effectively create gradients in both concentration and diffusion flux of water vapor along the groove height, leading to a varying nucleation rate along the groove height. Facilitated by this preferential nucleation, large condensate droplets are objected to a Laplace pressure and undergo a self-propulsion to detach from the surface with ~50% decrease in diameter compared with the superhydrophobic surface without macro-textured groove arrays. Our findings enrich the fundamental understanding of how macrotextures regulate microscopic wetting state, and such macrotextures can be combined with the state-of-the-art micro/nano fabrication technologies for energy-water nexus applications.
AB - On superhydrophobic surfaces, small condensate droplets exhibit a preferred self-propelled jumping by a coalescence-induced energy release, but large condensate droplets in several millimeters remain immobile. The accumulation of large condensate droplets leads to many problems such as shielding the growth of small droplets and increasing the thermal resistance of condensate. In this work, we present a largely unexplored strategy for enhancing the self-removal of large condensate droplets by the rational design of the millimetric macro-textured groove arrays (MGAs). In the condensation process, such macrotextures effectively create gradients in both concentration and diffusion flux of water vapor along the groove height, leading to a varying nucleation rate along the groove height. Facilitated by this preferential nucleation, large condensate droplets are objected to a Laplace pressure and undergo a self-propulsion to detach from the surface with ~50% decrease in diameter compared with the superhydrophobic surface without macro-textured groove arrays. Our findings enrich the fundamental understanding of how macrotextures regulate microscopic wetting state, and such macrotextures can be combined with the state-of-the-art micro/nano fabrication technologies for energy-water nexus applications.
KW - Condensation
KW - Diffusion
KW - Macrotexture
KW - Nucleation
KW - Superhydrophobic surface
UR - http://www.scopus.com/inward/record.url?scp=85091357645&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2020.126901
DO - 10.1016/j.cej.2020.126901
M3 - Journal article
AN - SCOPUS:85091357645
SN - 1385-8947
VL - 405
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 126901
ER -