Jumping droplets are interesting because of their applications in energy harvesting, heat transfer, anti-icing surfaces, and displays. Typically, droplets “jump” from a surface when two or more drops coalesce. Here, we demonstrate an approach to get a single droplet of liquid metal (eutectic gallium indium) to jump by using electrochemistry in a solution of 1M NaOH. Applying a positive potential to the metal (∼1 V relative to the open circuit potential) drives electrochemical surface oxidation that lowers the interfacial tension from ∼450 mN/m to ∼0 mN/m. In the low interfacial tension state, the droplet flattens due to gravity. Rapid switching to a negative potential (relative to the open circuit potential) reduces the surface oxide, returning the deformed droplet to a state of high interfacial tension. This rapid change in interfacial tension in the flattened state generates excess surface energy, which drives the droplet to return to a spherical shape with enough momentum that the liquid droplet jumps. This work is unique because (1) the jumping is controlled and tuned electrically, (2) the approach works with a single droplet, (3) it does not require a superhydrophobic surface, which is typically used to prevent droplets from adhering to the substrate, (4) the drops jump through a viscous medium rather than air, and (5) the potential energy obtained by the jumping drops is one order of magnitude higher than previous approaches. Yet, a limitation of this approach relative to conventional jumping drops is the need for electrolyte and a source of electricity to enable jumping. Herein, we characterize and optimize the jumping height (∼6 mm for a 3.6 mm diameter drop) by changing the reductive and oxidative potential and time.

1.
C.
Liu
,
M.
Zhao
,
Y.
Zheng
,
L.
Cheng
,
J.
Zhang
, and
C. A. T. H.
Tee
,
Langmuir
37
,
983
(
2021
).
2.
Y.
Nam
,
H.
Kim
, and
S.
Shin
,
Appl. Phys. Lett.
103
,
161601
(
2013
).
3.
R.
Enright
,
N.
Miljkovic
,
J.
Sprittles
,
K.
Nolan
,
R.
Mitchell
, and
E. N.
Wang
,
ACS Nano
8
,
10352
(
2014
).
4.
M.-K.
Kim
,
H.
Cha
,
P.
Birbarah
,
S.
Chavan
,
C.
Zhong
,
Y.
Xu
, and
N.
Miljkovic
,
Langmuir
31
,
13452
(
2015
).
5.
Z.
Yuan
,
X.
Zhang
,
H.
Hou
,
Z.
Hu
,
X.
Wu
, and
J.
Liu
,
Phys. Rev. Fluids
5
,
111601
(
2020
).
6.
J. B.
Boreyko
and
C.-H.
Chen
,
Phys. Rev. Lett.
103
,
184501
(
2009
).
7.
X.
Yan
,
L.
Zhang
,
S.
Sett
,
L.
Feng
,
C.
Zhao
,
Z.
Huang
,
H.
Vahabi
,
A. K.
Kota
,
F.
Chen
, and
N.
Miljkovic
,
ACS Nano
13
,
8169
(
2019
).
8.
M.
Kollera
and
U.
Grigull
,
Wärme Stoffübertrag.
2
,
31
(
1969
).
9.
R. L.
Chavez
,
F.
Liu
,
J. J.
Feng
, and
C. H.
Chen
,
Appl. Phys. Lett.
109
,
011601
(
2016
).
10.
G.
Chen
,
X.
Liu
,
S.
Li
,
M.
Dong
, and
D.
Jiang
,
Lab. Chip
18
,
1026
(
2018
).
11.
N.
Miljkovic
,
D. J.
Preston
,
R.
Enright
, and
E. N.
Wang
,
Appl. Phys. Lett.
105
,
013111
(
2014
).
12.
K. M.
Wisdom
,
J. A.
Watson
,
X.
Qu
,
F.
Liu
,
G. S.
Watson
, and
C.-H.
Chen
,
Proc. Natl. Acad. Sci. U. S. A.
110
,
7992
(
2013
).
13.
D.
Xing
,
R.
Wang
,
F.
Wu
, and
X.
Gao
,
ACS Appl. Mater. Interfaces
12
,
29946
(
2020
).
14.
R.
Enright
,
N.
Miljkovic
,
A.
Al-Obeidi
,
C. V.
Thompson
, and
E. N.
Wang
,
Langmuir
28
,
14424
(
2012
).
15.
N.
Miljkovic
,
R.
Enright
,
Y.
Nam
,
K.
Lopez
,
N.
Dou
,
J.
Sack
, and
E. N.
Wang
,
Nano Lett.
13
,
179
(
2013
).
16.
C.
Dietz
,
K.
Rykaczewski
,
A. G.
Fedorov
, and
Y.
Joshi
,
Appl. Phys. Lett.
97
,
033104
(
2010
).
17.
R.
Wen
,
S.
Xu
,
D.
Zhao
,
Y.-C.
Lee
,
X.
Ma
, and
R.
Yang
,
ACS Appl. Mater. Interfaces
9
,
44911
(
2017
).
18.
X.
Chen
,
J.
Wu
,
R.
Ma
,
M.
Hua
,
N.
Koratkar
,
S.
Yao
, and
Z.
Wang
,
Adv. Funct. Mater.
21
,
4617
(
2011
).
19.
N.
Miljkovic
,
R.
Enright
, and
E. N.
Wang
,
ACS Nano
6
,
1776
(
2012
).
20.
J. B.
Boreyko
,
Y.
Zhao
, and
C.-H.
Chen
,
Appl. Phys. Lett.
99
,
234105
(
2011
).
21.
A.
Pugsley
,
A.
Zacharopoulos
,
J.
Deb Mondol
, and
M.
Smyth
,
Int. J. Heat Mass Transfer
144
,
118660
(
2019
).
22.
J.
Chen
,
R.
Dou
,
D.
Cui
,
Q.
Zhang
,
Y.
Zhang
,
F.
Xu
,
X.
Zhou
,
J.
Wang
,
Y.
Song
, and
L.
Jiang
,
ACS Appl. Mater. Interfaces
5
,
4026
(
2013
).
23.
Q.
Zhang
,
M.
He
,
J.
Chen
,
J.
Wang
,
Y.
Song
, and
L.
Jiang
,
Chem. Commun.
49
,
4516
(
2013
).
24.
K.
Rykaczewski
,
J. H. J.
Scott
,
S.
Rajauria
,
J.
Chinn
,
A. M.
Chinn
, and
W.
Jones
,
Soft Matter
7
,
8749
(
2011
).
25.
N.
Miljkovic
,
D. J.
Preston
,
R.
Enright
, and
E. N.
Wang
,
Nat. Commun.
4
,
2517
(
2013
).
26.
S.
Jun Lee
,
S.
Lee
, and
K.
Hyoung Kang
,
Appl. Phys. Lett.
100
,
081604
(
2012
).
27.
K.
Ashoke Raman
,
R. K.
Jaiman
,
T.-S.
Lee
, and
H.-T.
Low
,
Int. J. Heat Mass Transfer
99
,
805
(
2016
).
28.
S. J.
Lee
,
S.
Lee
, and
K. H.
Kang
,
J. Visualization
14
,
259
(
2011
).
29.
A.
Cavalli
,
D. J.
Preston
,
E.
Tio
,
D. W.
Martin
,
N.
Miljkovic
,
E. N.
Wang
,
F.
Blanchette
, and
J. W. M.
Bush
,
Phys. Fluids
28
,
022101
(
2016
).
30.
A.
Merdasi
,
A.
Moosavi
, and
M. B.
Shafii
,
Mater. Res. Express
6
,
086333
(
2019
).
31.
C.
Stamatopoulos
,
P.
Bleuler
,
M.
Pfeiffer
,
S.
Hedtke
,
P.
Rudolf von Rohr
, and
C. M.
Franck
,
Langmuir
35
,
4876
(
2019
).
32.
J.
Jeong
,
J.-B.
Lee
,
S. K.
Chung
, and
D.
Kim
,
Lab Chip
19
,
3261
(
2019
).
33.
M. G.
Pollack
,
R. B.
Fair
, and
A. D.
Shenderov
,
Appl. Phys. Lett.
77
,
1725
(
2000
).
34.
S. K.
Cho
,
Y.
Zhao
, and
C.-J.
“CJ” Kim
,
Lab Chip
7
,
490
(
2007
).
35.
J.
Hong
,
Y. K.
Kim
,
D.-J.
Won
,
J.
Kim
, and
S. J.
Lee
,
Sci. Rep.
5
,
10685
(
2015
).
36.
S. K.
Cho
,
H.
Moon
, and
C.-J.
Kim
,
J. Microelectromech. Syst.
12
,
70
(
2003
).
37.
Y.
Lin
,
J.
Genzer
, and
M. D.
Dickey
,
Adv. Sci.
7
,
2000192
(
2020
).
38.
S. J.
French
,
D. J.
Saunders
, and
G. W.
Ingle
,
J. Phys. Chem.
42
,
265
(
1938
).
39.
J.-H.
Kim
,
S.
Kim
,
J.-H.
So
,
K.
Kim
, and
H.-J.
Koo
,
ACS Appl. Mater. Interfaces
10
,
17448
(
2018
).
40.
M. D.
Dickey
,
R. C.
Chiechi
,
R. J.
Larsen
,
E. A.
Weiss
,
D. A.
Weitz
, and
G. M.
Whitesides
,
Adv. Funct. Mater.
18
,
1097
(
2008
).
41.
A. R.
Jacob
,
D. P.
Parekh
,
M. D.
Dickey
, and
L. C.
Hsiao
,
Langmuir
35
,
11774
(
2019
).
42.
C. B.
Eaker
,
D. C.
Hight
,
J. D.
O'Regan
,
M. D.
Dickey
, and
K. E.
Daniels
,
Phys. Rev. Lett.
119
,
174502
(
2017
).
43.
D. R.
Arnott
,
W. J.
Baxter
, and
S. R.
Rouze
,
J. Electrochem. Soc.
129
,
2660
(
1982
).
44.
J. C.
Nelson
and
R. A.
Oriani
,
Corros. Sci.
34
,
307
(
1993
).
45.
M. R.
Khan
,
C.
Trlica
, and
M. D.
Dickey
,
Adv. Funct. Mater.
25
,
671
(
2015
).
46.
Q.
Van Overmeere
and
J.
Proost
,
Electrochim. Acta
56
,
10507
(
2011
).
47.
D. H.
Bradhurst
and
J. S. L.
Leach
,
J. Electrochem. Soc.
113
,
1245
(
1966
).
48.
M.
Song
,
K.
Kartawira
,
K. D.
Hillaire
,
C.
Li
,
C. B.
Eaker
,
A.
Kiani
,
K. E.
Daniels
, and
M. D.
Dickey
,
Proc. Natl. Acad. Sci.
117
,
202006122
(
2020
).
49.
M. R.
Khan
,
C. B.
Eaker
,
E. F.
Bowden
, and
M. D.
Dickey
,
Proc. Natl. Acad. Sci.
111
,
14047
(
2014
).
50.
S.
Chen
,
L.
Wang
,
Q.
Zhang
, and
J.
Liu
,
Sci. Bull.
63
,
1513
(
2018
).
51.
S.
Farokhirad
,
J. F.
Morris
, and
T.
Lee
,
Phys. Fluids
27
,
102102
(
2015
).
52.
J.-J.
Huang
,
H.
Huang
, and
J.-J.
Xu
,
Appl. Phys. Lett.
115
,
141602
(
2019
).
53.
F.-C.
Wang
,
F.
Yang
, and
Y.-P.
Zhao
,
Appl. Phys. Lett.
98
,
053112
(
2011
).
54.
J.
Kestin
,
M.
Sokolov
, and
W. A.
Wakeham
,
J. Phys. Chem. Ref. Data
7
,
941
(
1978
).
55.
S.-H.
Lee
,
M.
Seong
,
M. K.
Kwak
,
H.
Ko
,
M.
Kang
,
H. W.
Park
,
S. M.
Kang
, and
H. E.
Jeong
,
ACS Nano
12
,
10693
(
2018
).
56.
S.
Hutzler
,
J. C. F.
Ryan-Purcell
,
F. F.
Dunne
, and
D.
Weaire
,
Philos. Mag. Lett.
98
,
9
(
2018
).
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