TY - JOUR
T1 - Breaking Droplet Jumping Energy Conversion Limits with Superhydrophobic Microgrooves
AU - Peng, Qi
AU - Yan, Xiao
AU - Li, Jiaqi
AU - Li, Longnan
AU - Cha, Hyeongyun
AU - Ding, Yi
AU - Dang, Chao
AU - Jia, Li
AU - Miljkovic, Nenad
N1 - Funding Information:
This work was supported by the National Key R&D Program of China (2018YFB0604301) and China Scholarship Council (Grant 201907090086). N.M., X.Y., and L.L. gratefully acknowledge funding support from the Air Conditioning and Refrigeration Center, an NSF-founded I/UCRC at UIUC. N.M. gratefully acknowledges the support of the International Institute for Carbon Neutral Energy Research, sponsored by the Japanese Ministry of Education, Culture, Sports, Science and Technology. Scanning electron microscopy was carried out in part in the Materials Research Laboratory Central Facilities, University of Illinois.
PY - 2020/8/18
Y1 - 2020/8/18
N2 - Coalescence-induced droplet jumping has the potential to enhance the performance of a variety of applications including condensation heat transfer, surface self-cleaning, anti-icing, and defrosting to name a few. Here, we study droplet jumping on hierarchical microgrooved and nanostructured smooth superhydrophobic surfaces. We show that the confined microgroove structures play a key role in tailoring droplet coalescence hydrodynamics, which in turn affects the droplet jumping velocity and energy conversion efficiency. We observed self-jumping of individual deformed droplets within microgrooves having maximum surface-To-kinetic energy conversion efficiency of 8%. Furthermore, various coalescence-induced jumping modes were observed on the hierarchical microgrooved superhydrophobic surface. The microgroove structure enabled high droplet jumping velocity (≈0.74U) and energy conversion efficiency (≈46%) by enabling the coalescence of deformed droplets in microgrooves with undeformed droplets on adjacent plateaus. The jumping velocity and energy conversion efficiency enhancements are 1.93× and 6.67× higher than traditional coalescence-induced droplet jumping on smooth superhydrophobic surfaces. This work not only demonstrates high droplet jumping velocity and energy conversion efficiency but also demonstrates the key role played by macroscale structures on coalescence hydrodynamics and elucidates a method to further control droplet jumping physics for a plethora of applications.
AB - Coalescence-induced droplet jumping has the potential to enhance the performance of a variety of applications including condensation heat transfer, surface self-cleaning, anti-icing, and defrosting to name a few. Here, we study droplet jumping on hierarchical microgrooved and nanostructured smooth superhydrophobic surfaces. We show that the confined microgroove structures play a key role in tailoring droplet coalescence hydrodynamics, which in turn affects the droplet jumping velocity and energy conversion efficiency. We observed self-jumping of individual deformed droplets within microgrooves having maximum surface-To-kinetic energy conversion efficiency of 8%. Furthermore, various coalescence-induced jumping modes were observed on the hierarchical microgrooved superhydrophobic surface. The microgroove structure enabled high droplet jumping velocity (≈0.74U) and energy conversion efficiency (≈46%) by enabling the coalescence of deformed droplets in microgrooves with undeformed droplets on adjacent plateaus. The jumping velocity and energy conversion efficiency enhancements are 1.93× and 6.67× higher than traditional coalescence-induced droplet jumping on smooth superhydrophobic surfaces. This work not only demonstrates high droplet jumping velocity and energy conversion efficiency but also demonstrates the key role played by macroscale structures on coalescence hydrodynamics and elucidates a method to further control droplet jumping physics for a plethora of applications.
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U2 - 10.1021/acs.langmuir.0c01494
DO - 10.1021/acs.langmuir.0c01494
M3 - Article
C2 - 32689802
AN - SCOPUS:85089710971
VL - 36
SP - 9510
EP - 9522
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 32
ER -