The impact of droplets on solid surfaces is a crucial fluid phenomenon in the additive industry, biotechnology, and chemistry, where controlling impact dynamics and duration is essential. While extensive research has focused on flat substrates, our understanding of impact dynamics on curved surfaces remains limited. This study seeks to establish phase diagrams for the process of droplet impact on solid spheres and further quantitatively describe the effect of curvature through theoretical analysis. It aims to determine the critical conditions between different impact outcomes and also establish a scaling relationship for the contact time. Here, the post-impact outcome regimes occurring for a wide range of Weber numbers (We) from 1.2 to 173.8, diameter ratio (λ) of solid spheres to nanodroplets from 0.25 to 2, and surface wettability (θ) from 21° to 160°, through the molecular dynamics simulation method (MD) and theoretical analysis. The MD simulations reveal that the phase diagrams of droplet impacts on hydrophilic, hydrophobic, and superhydrophobic spheres differ, with specific distinctions focusing on rebound and three different forms of dripping. Furthermore, a theoretical model based on the principle of energy conservation during impact on superhydrophobic surfaces has been developed to predict the critical conditions between rebound and dripping states, showing good agreement with simulation results. Additionally, a new scaling relationship of contact time for droplet impact on superhydrophobic spherical surfaces has also been established by extending and modifying the existing models, which also agrees well with the simulated results. These insights provide a foundational understanding for designing surface structures.

1.
M.
Garbero
,
M.
Vanni
, and
G.
Baldi
, “
CFD modelling of a spray deposition process of paint
,”
Macromol. Symp.
187
,
719
730
(
2002
).
2.
J.
Kim
, “
Spray cooling heat transfer: The state of the art
,”
Int. J. Heat Fluid Flow
28
,
753
767
(
2007
).
3.
D. A.
Bolleddula
,
A.
Berchielli
, and
A.
Aliseda
, “
Impact of a heterogeneous liquid droplet on a dry surface: Application to the pharmaceutical industry
,”
Adv. Colloid Interface Sci.
159
,
144
159
(
2010
).
4.
J. Y.
Lee
,
J.
An
, and
C. K.
Chua
, “
Fundamentals and applications of 3D printing for novel materials
,”
Appl. Mater. Today
7
,
120
133
(
2017
).
5.
D.
Khojasteh
,
N. M.
Kazerooni
, and
M.
Marengo
, “
A review of liquid droplet impacting onto solid spherical particles: A physical pathway to encapsulation mechanisms
,”
J. Ind. Eng. Chem.
71
,
50
64
(
2019
).
6.
Y.
Wang
, “
Numerical study of a droplet impact on cylindrical objects: Towards the anti-icing property of power transmission lines
,”
Appl. Surf. Sci.
516
,
146155
(
2020
).
7.
R. P.
Patel
,
M. P.
Patel
, and
A. M.
Suthar
, “
Spray drying technology: An overview
,”
Indian J. Sci. Technol.
2
,
44
47
(
2009
).
8.
I.
Malgarinos
,
N.
Nikolopoulos
, and
M.
Gavaises
, “
Numerical investigation of heavy fuel droplet-particle collisions in the injection zone of a Fluid Catalytic Cracking reactor, Part I: Numerical model and 2D simulations
,”
Fuel Process. Technol.
156
,
317
330
(
2017
).
9.
S. A.
Banitabaei
and
A.
Amirfazli
, “
Droplet impact onto a solid sphere: Effect of wettability and impact velocity
,”
Phys. Fluids
29
,
062111
(
2017
).
10.
X. X.
Li
,
Y. C.
Fu
,
D.
Zheng
,
Y. H.
Fang
, and
Y. X.
Wang
, “
A numerical study of droplet impact on solid spheres: The effect of surface wettability, sphere size, and initial impact velocity
,”
Chem. Phys.
550
,
111314
(
2021
).
11.
Y. X.
Du
,
J.
Liu
,
Y. Z.
Li
,
J. Y.
Du
,
X. X.
Wu
, and
Q.
Min
, “
Numerical study on droplets impacting solid spheres: Effect of fluid properties and sphere diameter
,”
Colloid Surf., A
625
,
126862
(
2021
).
12.
L.
Xia
,
F. Z.
Chen
,
Z.
Yang
,
T.
Liu
,
Y. L.
Tian
, and
D. W.
Zhang
, “
Droplet impact dynamics on superhydrophobic surfaces with convex hemispherical shapes
,”
Int. J. Mech. Sci.
264
,
108824
(
2024
).
13.
X.
Liu
,
X.
Zhang
, and
J. C.
Min
, “
Droplet rebound and dripping during impact on small superhydrophobic spheres
,”
Phys. Fluids
34
,
032118
(
2022
).
14.
X. X.
Li
,
H. W.
Li
,
D.
Zheng
, and
Y. X.
Wang
, “
Many-body dissipative particle dynamics study of droplet impact on superhydrophobic spheres with different size
,”
Colloid Surf., A
618
,
126493
(
2021
).
15.
H. N.
Dalgamoni
and
X.
Yong
, “
Numerical and theoretical modeling of droplet impact on spherical surfaces
,”
Phys. Fluids
33
,
052112
(
2021
).
16.
M.
Benz
,
A.
Asperger
,
M.
Hamester
,
A.
Welle
,
S.
Heissler
, and
P. A.
Levkin
, “
A combined high-throughput and high-content platform for unified on-chip synthesis, characterization and biological screening
,”
Nat. Commun.
11
,
5391
(
2020
).
17.
A.
Ishijima
,
K.
Minamihata
,
S.
Yamaguchi
,
S.
Yamahira
,
R.
Ichikawa
,
E.
Kobayashi
,
M.
Iijima
,
Y.
Shibasaki
,
T.
Azuma
, and
T.
Nagamune
, “
Selective intracellular vaporisation of antibody-conjugated phase-change nano-droplets in vitro
,”
Sci. Rep.
7
,
44077
(
2017
).
18.
M. W.
Glasscott
,
A. D.
Pendergast
,
S.
Goines
,
A. R.
Bishop
,
A. T.
Hoang
,
C.
Renault
, and
J. E.
Dick
, “
Electrosynthesis of high-entropy metallic glass nanoparticles for designer, multi-functional electrocatalysis
,”
Nat. Commun.
10
,
2650
(
2019
).
19.
F.
Liu
,
G.
Ghigliotti
,
J. J.
Feng
, and
C. H.
Chen
, “
Numerical simulations of self-propelled jumping upon drop coalescence on nonwetting surfaces
,”
J. Fluid Mech.
752
,
39
65
(
2014
).
20.
T.
Kondo
and
K.
Ando
, “
Simulation of high-speed droplet impact against a dry/wet rigid wall for understanding the mechanism of liquid jet cleaning
,”
Phys. Fluids
31
,
013303
(
2019
).
21.
J.
Eggers
,
M. A.
Fontelos
,
C.
Josserand
, and
S.
Zaleski
, “
Drop dynamics after impact on a solid wall: Theory and simulations
,”
Phys. Fluids
22
,
062101
(
2010
).
22.
Z.
Liang
and
P.
Keblinski
, “
Coalescence-induced jumping of nanoscale droplets on super-hydrophobic surfaces
,”
Appl. Phys. Lett.
107
,
143105
(
2015
).
23.
F. F.
Xie
,
G.
Lu
,
X. D.
Wang
, and
B. B.
Wang
, “
Coalescence-induced jumping of two unequal-sized nanodroplets
,”
Langmuir
34
,
2734
2740
(
2018
).
24.
F. F.
Xie
,
G.
Lu
,
X. D.
Wang
, and
D. Q.
Wang
, “
Enhancement of coalescence-induced nanodroplet jumping on superhydrophobic surfaces
,”
Langmuir
34
,
11195
(
2018
).
25.
S.
Arora
,
J. M.
Fromental
,
S.
Mora
,
T.
Phou
,
L.
Ramos
, and
C.
Ligoure
, “
Impact of beads and drops on a repellent solid surface: A unified description
,”
Phys. Rev. Lett.
120
,
148003
(
2018
).
26.
V.
Zorba
,
E.
Stratakis
,
M.
Barberoglou
,
E.
Spanakis
,
P.
Tzanetakis
,
S. H.
Anastasiadis
, and
C.
Fotakis
, “
Biomimetic artificial surfaces quantitatively reproduce the water repellency of a lotus leaf
,”
Adv. Mater.
20
,
4049
4054
(
2008
).
27.
K.
Okumura
,
F.
Chevy
,
D.
Richard
,
D.
Quere
, and
C.
Clanet
, “
Water spring: A model for bouncing drops
,”
Europhys. Lett.
62
,
237
243
(
2003
).
28.
Y.
Tanaka
,
Y.
Yamazaki
, and
K.
Okumura
, “
Bouncing gel balls: Impact of soft gels onto rigid surface
,”
Europhys. Lett.
63
,
146
152
(
2003
).
29.
D.
Bartolo
,
F.
Bouamrirene
,
E.
Verneuil
,
A.
Buguin
,
P.
Silberzan
, and
S.
Moulinet
, “
Bouncing or sticky droplets: Impalement transitions on superhydrophobic micropatterned surfaces
,”
Europhys. Lett.
74
,
299
305
(
2006
).
30.
P.
Tsai
,
S.
Pacheco
,
C.
Pirat
,
L.
Lefferts
, and
D.
Lohse
, “
Drop impact upon micro-and nanostructured superhydrophobic surfaces
,”
Langmuir
25
,
12293
(
2009
).
31.
J. C.
Bird
,
J.
Dhiman
,
H. M.
Kwon
, and
K. K.
Varanasi
, “
Reducing the contact time of a bouncing drop
,”
Nature
503
,
385
388
(
2013
).
32.
F. F.
Xie
,
S. H.
Lv
,
Y. R.
Yang
, and
X. D.
Wang
, “
Contact time of a bouncing nanodroplet
,”
J. Phys. Chem. Lett.
11
,
2818
(
2020
).
33.
C.
Clanet
,
C.
Beguin
,
D.
Richard
, and
D.
Quéré
, “
Maximal deformation of an impacting drop
,”
J. Fluid Mech.
517
,
199
(
2004
).
34.
Y. F.
Wang
,
Y. B.
Wang
,
X.
He
,
B. X.
Zhang
,
Y. R.
Yang
,
X. D.
Wang
, and
D. J.
Lee
, “
Scaling laws of the maximum spreading factor for impact of nanodroplets on solid surfaces
,”
J. Fluid Mech.
937
,
A12
(
2022
).
35.
J. B.
Lee
,
D.
Derome
,
A.
Dolatabadi
, and
J.
Carmeliet
, “
Energy budget of liquid drop impact at maximum spreading: Numerical simulations and experiments
,”
Langmuir
32
,
1279
(
2016
).
36.
J. B.
Lee
,
D.
Derome
,
R.
Guyer
, and
J.
Carmeliet
, “
Modeling the maximum spreading of liquid droplets impacting wetting and nonwetting surfaces
,”
Langmuir
32
,
1299
(
2016
).
37.
T.
Mao
,
D. C.
Kuhn
, and
H.
Tran
, “
Spread and rebound of liquid droplets upon impact on flat surfaces
,”
AIChE J.
43
,
2169
(
1997
).
38.
M. P.
Fard
,
Y.
Qiao
,
S.
Chandra
, and
J.
Mostaghimi
, “
Capillary effects during droplet impact on a solid surface
,”
Phys. Fluids
8
,
650
(
1996
).
39.
C. W.
Visser
,
P. E.
Frommhold
,
S.
Wildeman
,
R.
Mettin
,
D.
Lohse
, and
C.
Sun
, “
Dynamics of high-speed micro-drop impact: Numerical simulations and experiments at frame-to-frame times below 100 ns
,”
Soft Matter
11
,
1708
(
2015
).
40.
C. W.
Visser
,
Y.
Tagawa
,
C.
Sun
, and
D.
Lohse
, “
Microdroplet impact at very high velocity
,”
Soft Matter
8
,
10732
(
2012
).
41.
S.
Wildeman
,
C. W.
Visser
,
C.
Sun
, and
D.
Lohse
, “
On the spreading of impacting drops
,”
J. Fluid Mech.
805
,
636
655
(
2016
).
42.
C.
Antonini
,
A.
Amirfazli
, and
M.
Marengo
, “
Drop impact and wettability: From hydrophilic to superhydrophobic surfaces
,”
Phys. Fluids
24
,
102104
(
2012
).
43.
T.
Gilet
and
J. W. M.
Bush
, “
Droplets bouncing on a wet, inclined surface
,”
Phys. Fluids
24
,
122103
(
2012
).
44.
H. M.
Huang
and
X. P.
Chen
, “
Energetic analysis of drop's maximum spreading on solid surface with low impact speed
,”
Phys. Fluids
30
,
022106
(
2018
).
45.
X. H.
Li
,
X. X.
Zhang
, and
M.
Chen
, “
Estimation of viscous dissipation in nanodroplet impact and spreading
,”
Phys. Fluids
27
,
052007
(
2015
).
46.
Z. J.
Yin
,
Z. L.
Ding
,
X. G.
Ma
,
X. P.
Zhang
, and
Y.
Xia
, “
Molecular dynamics simulations of single water nanodroplet impinging vertically on curved copper substrate
,”
Microgravity Sci. Technol.
31
,
749
757
(
2019
).
47.
L. X.
Zhan
,
H.
Chen
,
H.
Zhou
,
J. W.
Chen
,
H.
Wu
, and
L. J.
Yang
, “
Droplet-particle collision dynamics: A molecular dynamics simulation
,”
Powder Technol.
422
,
118456
(
2023
).
48.
Y. F.
Wang
,
Q.
Ma
,
B. J.
Wei
,
S. R.
Gao
,
Y. R.
Yang
,
S. F.
Zheng
,
D. J.
Lee
, and
X. D.
Wang
, “
Impact of nanodroplets on solid spheres
,”
Phys. Fluids
35
,
2082118
(
2023
).
49.
V.
Molinero
and
E. B.
Moore
, “
Water modeled as an intermediate element between carbon and silicon
,”
J. Phys. Chem. B
113
,
4008
4016
(
2009
).
50.
Q.
Ma
,
Y. F.
Wang
,
Y. B.
Wang
,
X.
He
,
S. F.
Zheng
,
Y. R.
Yang
,
X. D.
Wang
, and
D. J.
Lee
, “
Phase diagram for nanodroplet impact on solid surfaces
,”
Phys. Fluids
33
,
102007
(
2021
).
51.
A.
Stukowski
, “
Visualization and analysis of atomistic simulation data with OVITO the open visualization tool
,”
Modell. Simul. Mater. Sci. Eng.
18
,
015012
(
2010
).
52.
B. X.
Li
,
X. H.
Li
, and
M.
Chen
, “
Spreading and breakup of nanodroplet impinging on surface
,”
Phys. Fluids
29
,
012003
(
2017
).
53.
Y. F.
Wang
,
Y. B.
Wang
,
F. F.
Xie
,
J. Y.
Liu
,
S. L.
Wang
,
Y. R.
Yang
,
S. R.
Gao
, and
X. D.
Wang
, “
Spreading and retraction kinetics for impact of nanodroplets on hydrophobic surfaces
,”
Phys. Fluids
35
,
092005
(
2020
).
54.
I.
Yoon
and
S.
Shin
, “
Direct numerical simulation of droplet collision with stationary spherical particle: A comprehensive map of outcomes
,”
Int. J. Multiphase Flow
135
,
103503
(
2021
).
55.
J.
Palacios
,
J.
Hernández
,
P.
Gómez
,
C.
Zanzi
, and
J.
López
, “
Experimental study of splashing patterns and the splashing/deposition threshold in drop impacts onto dry smooth solid surfaces
,”
Exp. Therm. Fluid Sci.
44
,
571
582
(
2013
).
56.
I.
Bischofberger
,
K. W.
Mauser
, and
S. R.
Nagel
, “
Seeing the invisible-air vortices around a splashing drop
,”
Phys. Fluids
25
,
091110
(
2013
).
57.
Y. B.
Wang
,
Y. F.
Wang
,
X.
Wang
,
B. X.
Zhang
,
Y. R.
Yang
,
D. J.
Li
,
X. D.
Wang
, and
M.
Chen
, “
Splash of impacting nanodroplets on solid surfaces
,”
Phys. Rev. Fluids
6
,
094201
(
2021
).
58.
R.
Rioboo
,
M.
Marengo
, and
C.
Tropea
, “
Time evolution of liquid drop impact onto solid, dry surfaces
,”
Exp. Fluids
33
,
112
124
(
2002
).
59.
D.
Richard
,
C.
Clanet
, and
D.
Quéré
, “
Contact time of a bouncing drop
,”
Nature
417
,
811
811
(
2002
).
60.
J.
Han
,
W.
Kim
,
C.
Bae
,
D.
Lee
,
S.
Shin
,
Y.
Nam
, and
C.
Lee
, “
Contact time on curved superhydrophobic surfaces
,”
Phys. Rev. E
101
,
043108
(
2020
).
61.
L.
Feng
,
M.
Yang
,
X.
Shi
,
Y.
Liu
,
Y.
Wang
, and
X.
Qiang
, “
Copper-based superhydrophobic materials with long-term durability, stability, regenerability, and self-cleaning property
,”
Colloid Surf., A
508
,
39
47
(
2016
).
62.
N.
Wang
,
D.
Xiong
,
Y.
Deng
,
Y.
Shi
, and
K.
Wang
, “
Mechanically robust superhydrophobic steel surface with anti-icing, UV-durability, and corrosion resistance properties
,”
ACS Appl. Mater. Interfaces
7
,
6260
6272
(
2015
).
63.
J.
Chao
,
J.
Feng
,
F.
Chen
,
B.
Wang
,
Y.
Tian
, and
D.
Zhang
, “
Fabrication of superamphiphobic surfaces with controllable oil adhesion in air
,”
Colloid Surf., A
610
,
125708
(
2021
).
64.
N. J.
Shirtcliffe
,
G.
McHale
,
M. I.
Newton
, and
Y.
Zhang
, “
Superhydrophobic copper tubes with possible flow enhancement and drag reduction
,”
ACS Appl. Mater. Interfaces
1
,
1316
1323
(
2009
).
65.
Y.
Liu
,
L.
Moevius
,
X.
Xu
,
T.
Qian
,
J. M.
Yeomans
, and
Z.
Wang
, “
Pancake bouncing on superhydrophobic surfaces
,”
Nat. Phys.
10
,
515
519
(
2014
).
66.
X.
Zhang
,
B.
Ji
,
X.
Liu
,
S.
Ding
,
X.
Wu
, and
J.
Min
, “
Maximum spreading and energy analysis of ellipsoidal impact droplets
,”
Phys. Fluids
33
,
052108
(
2021
).
67.
D.
Seveno
,
T. D.
Blake
, and
J. D.
Coninck
, “
Young's Equation at the Nanoscale
,”
Phys. Rev. Lett.
111
,
096101
(
2013
).
68.
H.
Yan
,
J. A.
Wei
,
S. W.
Cui
,
S. H.
Xu
,
Z. W.
Sun
, and
R. Z.
Zhu
, “
On the applicability of Young–Laplace equation for nanoscale liquid drops
,”
Russ. J. Phys. Chem. A.
90
,
635
640
(
2016
).
69.
Q.
Ma
,
Y. F.
Wang
,
Y. B.
Wang
,
B. X.
Zhang
,
S. F.
Zheng
,
T. R.
Yang
,
D. J.
Lee
, and
X. D.
Wang
, “
Scaling laws for the contact time of impacting nanodroplets: From hydrophobic to superhydrophobic surfaces
,”
Phys. Fluids
35
,
062003
(
2023
).
70.
H.
Zhang
,
X.
Yi
,
Y.
Du
,
R.
Zhang
,
X.
Zhang
,
F.
He
,
F.
Niu
, and
P.
Hao
, “
Dynamic behavior of water drops impacting on cylindrical superhydrophobic surfaces
,”
Phys. Fluids
31
,
032104
(
2019
).
71.
É.
Lorenceau
,
C.
Clanet
, and
D.
Quéré
, “
Capturing drops with a thin fiber
,”
J. Colloid Interface Sci.
279
,
192
197
(
2004
).
72.
S. G.
Kim
and
W.
Kim
, “
Drop impact on a fiber
,”
Phys. Fluids
28
,
042001
(
2016
).
You do not currently have access to this content.