The objective of this work is to study the chemical reaction between sodium alginate drop and calcium chloride film and instantaneous formation of calcium alginate gel. The complexity of this work is the simultaneous effect of both liquid and solid surface on drop impact gelation process. The sodium alginate concentration in the drop fluid, liquid film thickness, and drop impingement height are varied and the observations are captured using a high speed camera. Several interesting phenomena like splashing and jet break up occur depending on the drop impingement velocity, drop concentration, and film thickness. Crosslinking reaction and mixing mechanisms are schematically explained accounting the role of capillary wave propagation within the liquid film. A mathematical model on drop spreading on the solid surface after penetrating the liquid film is developed to predict the theoretical gel length for ultrathin and thin film regimes. Maximum spreading diameter of the drop postimpact on the liquid film is predicted from the model. However, the experimentally measured solidified gel length deviates from the theoretical values and these deviations are utilized to measure the rate of crosslinking gelation and instantaneous solidification. Different hydrodynamic parameters such as the crater depth, crater contact time, and crater dissipation energy are evaluated for the dynamics of gelation. Finally, the kinetics of gelation with the variation of liquid film thickness are determined for alginate drop concentrations and drop impingement heights.

1.
B.
Samuel
,
H.
Zhao
, and
K.-Y.
Law
, “
Study of wetting and adhesion interactions between water and various polymer and superhydrophobic surfaces
,”
J. Phys. Chem. C
115
,
14852
(
2011
).
2.
S.
Chandra
and
C. T.
Avedisian
, “
On the collision of a droplet with a solid surface
,”
Proc. R. Soc. London, Ser. A
432
,
13
(
1991
).
3.
R. D.
Reitz
, “
Combustion and ignition chemistry in internal combustion engines
,”
Int. J. Engine Res.
14
,
411
(
2013
).
4.
A.
Terzis
,
M.
Kirsch
,
V.
Vaikuntanathan
,
A.
Geppert
,
G.
Lamanna
, and
B.
Weigand
, “
Splashing characteristics of diesel exhaust fluid (AdBlue) droplets impacting on urea-water solution films
,”
Exp. Therm. Fluid Sci.
102
,
152
(
2019
).
5.
A.-B.
Wang
and
C.-C.
Chen
, “
Splashing impact of a single drop onto very thin liquid films
,”
Phys. Fluids
12
,
2155
(
2000
).
6.
A. L.
Yarin
, “
Drop impact dynamics: Splashing, spreading, receding, bouncing…
,”
Annu. Rev. Fluid Mech.
38
,
159
(
2006
).
7.
C.
Josserand
,
P.
Ray
, and
S.
Zaleski
, “
Droplet impact on a thin liquid film: Anatomy of the splash
,”
J. Fluid Mech.
802
,
775
(
2016
).
8.
N.
Chen
,
H.
Chen
, and
A.
Amirfazli
, “
Drop impact onto a thin film: Miscibility effect
,”
Phys. Fluids
29
,
092106
(
2017
).
9.
Z.
Che
and
O. K.
Matar
, “
Impact of droplets on immiscible liquid films
,”
Soft Matter
14
,
1540
(
2018
).
10.
X.
Tang
,
A.
Saha
,
C. K.
Law
, and
C.
Sun
, “
Bouncing-to-merging transition in drop impact on liquid film: Role of liquid viscosity
,”
Langmuir
34
,
2654
(
2018
).
11.
Z.
Che
and
O. K.
Matar
, “
Impact of droplets on liquid films in the presence of surfactant
,”
Langmuir
33
,
12140
(
2017
).
12.
Y.
Guo
and
Y.
Lian
, “
Numerical investigation of oblique impact of multiple drops on thin liquid film
,”
J. Colloid Interface Sci.
530
,
586
(
2018
).
13.
S.
Shaikh
,
G.
Toyofuku
,
R.
Hoang
, and
J. O.
Marston
, “
Immiscible impact dynamics of droplets onto millimetric films
,”
Exp. Fluids
59
,
7
(
2017
).
14.
H. M.
Kittel
,
I. V.
Roisman
, and
C.
Tropea
, “
Splash of a drop impacting onto a solid substrate wetted by a thin film of another liquid
,”
Phys. Rev. Fluids
3
,
073601
(
2018
).
15.
H. M.
Kittel
,
I. V.
Roisman
, and
C.
Tropea
, “
Splashing of a very viscous liquid drop impacting onto a solid wall wetted by another liquid
,” in
Conference: ILASS2017—28th European Conference on Liquid Atomization and Spray Systems
(
Valencia, Spain
,
2017
).
16.
Y.
Zhang
,
P.
Liu
,
Q.
Qu
,
F.
Liu
, and
R. K.
Agarwal
,
Numerical Simulation of a Droplet Impacting upon Films with Varied Liquid Properties
(
AIAA SciTech Forum
,
Grapevine, Texas
,
2017
).
17.
Y.
Zhang
,
P.
Liu
,
Q.
Qu
, and
T.
Hu
, “
Energy conversion during the crown evolution of the drop impact upon films
,”
Int. J. Multiphase Flow
115
,
40
(
2019
).
18.
C.
Guiying
,
G.
Yali
,
W.
Lan
, and
S.
Shengqiang
, “
Simulation of dynamic characteristics of droplet impact on liquid film
,”
Int. J. Low-Carbon Technol.
9
,
150
(
2014
).
19.
K. A.
Raman
,
R. K.
Jaiman
,
T. S.
Lee
, and
H. T.
Low
, “
On the dynamics of crown structure in simultaneous two droplets impact onto stationary and moving liquid film
,”
Comput. Fluids
107
,
285
(
2015
).
20.
J.
Wu
,
C.
Liu
, and
N.
Zhao
, “
Dynamics of falling droplets impact on a liquid film: Hybrid lattice Boltzmann simulation
,”
Colloids Surf., A
472
,
92
(
2015
).
21.
X.
Tang
,
A.
Saha
,
C. K.
Law
, and
C.
Sun
, “
Bouncing drop on liquid film: Dynamics of interfacial gas layer
,”
Phys. Fluids
31
,
013304
(
2019
).
22.
J.
Hao
and
S. I.
Green
, “
Splash threshold of a droplet impacting a moving substrate
,”
Phys. Fluids
29
,
012103
(
2017
).
23.
J.
Hao
, “
Effect of surface roughness on droplet splashing
,”
Phys. Fluids
29
,
122105
(
2017
).
24.
W.
Wang
,
C.
Ji
,
F.
Lin
,
X.
Wei
, and
J.
Zou
, “
Formation of water in oil in water particles by drop impact on an oil layer
,”
Phys. Fluids
31
,
037107
(
2019
).
25.
N. E.
Ersoy
and
M.
Eslamian
, “
Capillary surface wave formation and mixing of miscible liquids during droplet impact onto a liquid film
,”
Phys. Fluids
31
,
012107
(
2019
).
26.
B. F.
Gibbs
,
S.
Kermasha
,
I.
Alli
, and
C. N.
Mulligan
, “
Encapsulation in the food industry: A review
,”
Int. J. Food Sci. Nutr.
50
,
213
(
1999
).
27.
S. B.
Doherty
,
V. L.
Gee
,
R. P.
Ross
,
C.
Stanton
,
G. F.
Fitzgerald
, and
A.
Brodkorb
, “
Development and characterisation of whey protein micro-beads as potential matrices for probiotic protection
,”
Food Hydrocolloids
25
,
1604
(
2011
).
28.
X.
Liu
,
L. H.
Nielsen
,
S. N.
Kłodzińska
,
H. M.
Nielsen
,
H.
Qu
,
L. P.
Christensen
,
J.
Rantanen
, and
M.
Yang
, “
Ciprofloxacin-loaded sodium alginate/poly (lactic-co-glycolic acid) electrospun fibrous mats for wound healing
,”
Eur. J. Pharm. Biopharm.
123
,
42
(
2018
).
29.
H. H.
Tønnesen
and
J.
Karlsen
, “
Alginate in drug delivery systems
,”
Drug Dev. Ind. Pharm.
28
,
621
(
2002
).
30.
Z.
Zhang
,
R.
Zhang
,
L.
Zou
, and
D. J.
McClements
, “
Protein encapsulation in alginate hydrogel beads: Effect of pH on microgel stability, protein retention and protein release
,”
Food Hydrocolloids
58
,
308
(
2016
).
31.
L.
Yu
,
Q.
Sun
,
Y.
Hui
,
A.
Seth
,
N.
Petrovsky
, and
C.-X.
Zhao
, “
Microfluidic formation of core-shell alginate microparticles for protein encapsulation and controlled release
,”
J. Colloid Interface Sci.
539
,
497
(
2019
).
32.
Y.
Teramura
,
O. P.
Oommen
,
J.
Olerud
,
J.
Hilborn
, and
B.
Nilsson
, “
Microencapsulation of cells, including islets, within stable ultra-thin membranes of maleimide-conjugated PEG-lipid with multifunctional crosslinkers
,”
Biomaterials
34
,
2683
(
2013
).
33.
S.
Baek
,
S. H.
Joo
, and
M.
Toborek
, “
Treatment of antibiotic-resistant bacteria by encapsulation of ZnO nanoparticles in an alginate biopolymer: Insights into treatment mechanisms
,”
J. Hazard. Mater.
373
,
122
(
2019
).
34.
J.
Cui
,
X.
Li
,
Z.
Pei
, and
Y.
Pei
, “
A long-term stable and environmental friendly self-healing coating with polyaniline/sodium alginate microcapsule structure for corrosion protection of water-delivery pipelines
,”
Chem. Eng. J.
358
,
379
(
2019
).
35.
J.
Wu
,
H.
Zheng
,
F.
Zhang
,
R. J.
Zeng
, and
B.
Xing
, “
Iron-carbon composite from carbonization of iron-crosslinked sodium alginate for Cr(VI) removal
,”
Chem. Eng. J.
362
,
21
(
2019
).
36.
Q.
Li
,
Y.
Li
,
X.
Ma
,
Q.
Du
,
K.
Sui
,
D.
Wang
,
C.
Wang
,
H.
Li
, and
Y.
Xia
, “
Filtration and adsorption properties of porous calcium alginate membrane for methylene blue removal from water
,”
Chem. Eng. J.
316
,
623
(
2017
).
37.
G. A.
Paredes Juárez
,
M.
Spasojevic
,
M. M.
Faas
, and
P.
de Vos
, “
Immunological and technical considerations in application of alginate-based microencapsulation systems
,”
Front. Bioeng. Biotechnol.
2
,
26
(
2014
).
38.
B. T.
Stokke
,
O.
Smidsroed
,
P.
Bruheim
, and
G.
Skjaak-Braek
, “
Distribution of uronate residues in alginate chains in relation to alginate gelling properties
,”
Macromolecules
24
,
4637
(
1991
).
39.
F.
Davarc
ı,
D.
Turan
,
B.
Ozcelik
, and
D.
Poncelet
, “
The influence of solution viscosities and surface tension on calcium-alginate microbead formation using dripping technique
,”
Food Hydrocolloids
62
,
119
(
2017
).
40.
S.
Abang
,
E. S.
Chan
, and
D.
Poncelet
, “
Effects of process variables on the encapsulation of oil in ca-alginate capsules using an inverse gelation technique
,”
J. Microencapsulation
29
,
417
(
2012
).
41.
T.-C.
Lin
, “
Investigation on drop dynamics during formation and hardening process of a microcapsule
,”
J. Aeronaut., Astronaut. Aviat., Ser. A
44
(
1
),
1
8
(
2012
).
42.
P.
Smrdel
,
M.
Bogataj
, and
A.
Mrhar
, “
The influence of selected parameters on the size and shape of alginate beads prepared by ionotropic gelation
,”
Sci. Pharm.
76
,
77
(
2008
).
43.
E.-S.
Chan
,
B.-B.
Lee
,
P.
Ravindra
, and
D.
Poncelet
, “
Prediction models for shape and size of ca-alginate macrobeads produced through extrusion–dripping method
,”
J. Colloid Interface Sci.
338
,
63
(
2009
).
44.
J.
Li
,
Y.
Wu
,
J.
He
, and
Y.
Huang
, “
A new insight to the effect of calcium concentration on gelation process and physical properties of alginate films
,”
J. Mater. Sci.
51
,
5791
(
2016
).
45.
K.
Haldar
and
S.
Chakraborty
, “
Effect of liquid pool concentration on chemically reactive drop impact gelation process
,”
J. Colloid Interface Sci.
528
,
156
(
2018
).
46.
K.
Haldar
and
S.
Chakraborty
, “
Role of chemical reaction and drag force during drop impact gelation process
,”
Colloids Surf., A
559
,
401
(
2018
).
47.
Y.
Zhang
,
Y.
Yong
,
D.
An
,
W.
Song
,
Q.
Liu
,
L.
Wang
,
Y.
Pardo
,
V. R.
Kern
,
P. H.
Steen
,
W.
Hong
,
Z.
Liu
, and
M.
Ma
, “
A drip-crosslinked tough hydrogel
,”
Polymer
135
,
327
(
2018
).
48.
D.
Caccavo
,
S.
Cascone
,
G.
Lamberti
, and
A. A.
Barba
, “
Hydrogels: Experimental characterization and mathematical modelling of their mechanical and diffusive behaviour
,”
Chem. Soc. Rev.
47
,
2357
(
2018
).
49.
R. B.
Abernethy
,
R. P.
Benedict
, and
R. B.
Dowdell
, “
ASME measurement uncertainty
,”
J. Fluids Eng.
107
,
161
(
1985
).
50.
D.
Cole
,
The Splashing Morphology of Liquid-Liquid Impacts
(
James Cook University
,
2007
).
51.
J.
de Ruiter
,
R. E.
Pepper
, and
H. A.
Stone
, “
Thickness of the rim of an expanding lamella near the splash threshold
,”
Phys. Fluids
22
,
022104
(
2010
).
52.
F.
Wang
,
L.
Yang
,
L.
Wang
,
Y.
Zhu
, and
T.
Fang
, “
Maximum spread of droplet impacting onto solid surfaces with different wettabilities: Adopting a rim-lamella shape
,”
Langmuir
35
,
3204
(
2019
).
53.
Q.
Deng
,
A. V.
Anilkumar
, and
T. G.
Wang
, “
The phenomenon of bubble entrapment during capsule formation
,”
J. Colloid Interface Sci.
333
,
523
(
2009
).
54.
H.
Park
,
W. W.
Carr
,
J.
Zhu
, and
J. F.
Morris
, “
Single drop impaction on a solid surface
,”
AIChE J.
49
,
2461
(
2003
).
55.
T. C.
de Goede
,
K. G.
de Bruin
,
N.
Shahidzadeh
, and
D.
Bonn
, “
Predicting the maximum spreading of a liquid drop impacting on a solid surface: Effect of surface tension and entrapped air layer
,”
Phys. Rev. Fluids
4
,
053602
(
2019
).
56.
X.
Tang
,
A.
Saha
,
C. K.
Law
, and
C.
Sun
, “
Nonmonotonic response of drop impacting on liquid film: Mechanism and scaling
,”
Soft Matter
12
,
4521
(
2016
).
57.
T.
Supakar
,
M.
Moradiafrapoli
,
G. F.
Christopher
, and
J. O.
Marston
, “
Spreading, encapsulation and transition to arrested shapes during drop impact onto hydrophobic powders
,”
J. Colloid Interface Sci.
468
,
10
(
2016
).
58.
O. G.
Engel
, “
Initial pressure, initial flow velocity, and the time dependence of crater depth in fluid impacts
,”
J. Appl. Phys.
38
,
3935
(
1967
).

Supplementary Material

You do not currently have access to this content.