microemulsions: basic theory and structure...
TRANSCRIPT
University of Cologne
Microemulsions: Basic Theory
and
Structure Kinetics
Dr. Helge Klemmer Physical Chemistry, University of Cologne, D-50939 Köln,
Germany
MN-C-WP/c
Sommersemester 2014
University of Cologne
Low surfactant content, low energy input: emulsions
(usually micrometer size, very instable)
Low surfactant content, high energy input: nanoemulsions
(usually nanometer size, slightly kinetically stable)
High surfactant content, just thermal energy: microemulsions
(lower nanometer size, thermodynamically stable)
Non-amphiphile systems: e.g. Pickering emulsions
2
It‘s the amphiphile content that matters
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Microemulsions
hydrophililic —hydrophobic—amphiphilic
component
(A) — (B) — (C)
thermodynamically stable, macroscopically homogeneous
but nano-structured phases of at least 3 components
water glycerol
monomers
n-alkanes triglycerides, monomers
super-critical fluids
non-ionic & ionic
surfactants
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Binary Water – Surfactant Systems / Surfactant types
non-ionic surfactants
ethylene glycol monoalkyl ether (CiEj)
alkylpolyglucoside (CiGj)
ionic surfactants
sodium bis(2-ethylhexyl) sulphosuccinate (AOT) anionic
dodecyl trimethylammonium bromide (DTAB) cationic
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Binary side-systems
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Water (A) – CiEj (B) Systems / upper miscibility gap
a
A C
2
cp
CA
C
mm
m
T
tie-line
critical point cp
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Water (A) – C12Ej (B) / Variation of j
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Water (A) – CiEj (B) / Micelle formation - cmc
c
1e-7 1e-6 1e-5 1e-4 1e-3 1e-2
/
mN
m-1
0
10
20
30
40
50
60
70
80
H2O - Tensid
cmc
TpdA
dE
,
Gibbs adsorptions isotherm:
Tpcd
d
RT ,ln
1
Surfactant head group area:
ANa
1
Surface tension:
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Water – CiEj Systems / Liquid crystalline phases
micellar cubic (I1):
hexagonal (H1):
bicontinuous cubic (V1):
lamellar (La):
+ inverted liquid crystalline phases:
V2, H2, I2
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10 0.001 0.01 0.1 1
T /
°C
0
10
20
30
40
50
60
70
80
90
2
1
spheres
cylinders
networks
Water – C12E6 / more self-assembly
wB
T /
°C
1
2
32_
T1 T1
T2
T2
T3
T3
H2O / C
iE
j
oil
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11
Water – C12E5 System / dilute self-assembled phases
/ wt%
0.001 0.01 0.1 1 10 1000
20
40
60
80
100
C12E6
C12E5
C12E4
2
1
/ wt%
0.001 0.01 0.1 1 10 100
T /
°C
0
20
40
60
80
100
L1
L1'+L3
L3
La
L2
H1
cmc
L1'+L1''
L1'+L2
wB
T /
°C
1
2
32_
T1 T1
T2
T2
T3
T3
H2O / C
iE
j
oil
L2: reversed micelles
dilute lamellae
L3: isotropic bi-
layer sponge-
phase
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Gibbs phase prism
p = constant
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Sections through the phase prism
BA
B
mm
m
a
CBA
C
mmm
m
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Isothermal sections - phase inversion
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Sections through the phase prism
BA
B
mm
m
a
CBA
C
mmm
m
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Isoplethal T()-section I
~
Measure of
Efficieny:
Phase inversion:
Monomeric
solubility:
T~
0
F = 0.50 = const.
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Isoplethal T()-section II
F = 0.50 = const.
H2O - n-octane - CiEj
= 0.5
0.0 0.1 0.2 0.3 0.4 0.5
0
20
40
60
0
20
40
60
T / °C
0
20
40
60
0
20
40
60
80
C10E4
C8E3
C6E2
1
1
13
32
2
23
C12E5
T / °C
T / °C
T / °C
La3
La
La
2_
2_
2_
1
2_
V
H2O – n-octane – CiEj
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Efficiency – Phase inversion temperature
F = 0.50 = const.
H2O – n-octane – CiEj
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Phase behaviour – Interfacial tensions
Microemulsions, T. Sottmann and R. Strey in Fundamentals of Interface and Colloid Science,
Volume V, edited by J. Lyklema, Academic Press (2005)
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Variation of oil/water-interfacial tension
T. Sottmann and R. Strey, J. Chem. Phys. 106, 8606 (1997)
T / °C
0 10 20 30 40 50 60 70
ab /
mN
m-1
10-4
10-3
10-2
10-1
100
H2O - n-C8H18 - CiEj
C12E5
C10E4
C8E3
C6E2
C4E1
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Microstructure
Techniques:
direct: Transmission Electron Microscopy (TEM)
indirect: Scattering Techniques
• Small Angle Neutron Scattering (SANS)
• Small Angle X-Ray Scattering
• Dynamic Light Scattering
Diffusion NMR
Electric Conductivity
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R. Strey, Colloid Polym. Sci., 272 (8), 1005 (1994).
F = 0.50 = const.
Microstructure
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Microstructure – Length Scales
Small angle neutron scattering (SANS)
q / Å-1
10-3 10-2 10-1 100
I(q
) /
cm-1
10-1
100
101
102
103
D2O - n-C8D18 - C12E5
a=0.0707, wB=0.0561, T=18°C
S(q)
P(q)
I(q)
r = 61.2 Å
= 9.7 Å
t = 6.0 Å
Iincoh= 0.125 cm-1
o/w
q / Å-1
10-3 10-2 10-1 100
I(q
) /
cm-1
10-1
100
101
102
103
D2O - n-C8D18 - C12E5
b=0.1260, wA=0.0959, T=46°C
S(q)
P(q)
I(q)
r = 50.0 Å
= 12.0 Å
t = 6.0 Å
Iincoh= 0.16 cm-1
w/o
M. Gradzielski, D. Langevin, L. Magid, and R. Strey, J. Phys. Chem. 99, 13232 (1995)
bicontinuous
D2O - n-octane - C12E5
q / Å-1
10-3 10-2 10-1
I ( q
) /
cm-1
10-1
100
101
102
103
104
105
106
107
108
109
1010
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.9
M. Teubner and R. Strey, J. Chem. Phys. 87, 3195 (1987)
University of Cologne 24 Redrawn from:
Strey, R., Colloid Polym. Sci., 1994, 272 (8), 1005.
Gompper, G., Kroll, D. M., Phys. Rev. Lett., 1998, 81, 2284.
Non-ionic surfactant (C)
H2O (A) alkane (B)
CB
Cb
mm
m
BA
B
mm
m
a
Sections through the phase prism
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The T(wA)-Cut
25
D2O/NaCl – cyclohexane-h12 – C10E5 e = 0.001, b=0.05, T=24.50°C
total
AA
m
mw
CB
Cb
mm
m
A
NaCl
m
me
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The Mixing Pathway
26
D2O/NaCl – cyclohexane-h12 – C10E5 e = 0.001, b=0.05, T=24.50°C
total
AA
m
mw
CB
Cb
mm
m
A
NaCl
m
me
D2O/NaCl (A) cyclohexane (B)
1
2
C10E5 (C)
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High temperature stability:
DT ≤ 0.1 K for 273 K ≤ T ≤ 343 K
BioLogic stopped flow combined
with:
The Experimental Setup
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D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
Microemulsion Formation Kinetics
University of Cologne 29
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
Microemulsion Formation Kinetics
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D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
Microemulsion Formation Kinetics
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D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
University of Cologne 32
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
University of Cologne 33
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms t = 134 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 539 ms
34
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 539 ms
35
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 891 ms
36
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 1408 ms
37
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 2163 ms
38
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 3269 ms
39
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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t = 180000 ms
40
D2O/NaCl – cyclohexane-h12 – C10E5
b = 0.05
e = 0.001 T = 24.50°C
wA = 0.11
D2O/NaCl
c-B6/C10E5
t = 22 ms
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
Microemulsion Formation Kinetics
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twater-uptake = (430±35) ms
t
t
eAt
Fdrop
Time-resolved Water Uptake
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µE,0µE reAtr
t
t
42
twater-uptake = (430±35) ms
tradial growth = (260±99) ms
Time-resolved Radial Growth
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The Influence of Amphiphilic Polymers
D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05
Bulk contrast
D2O/NaCl – cyclohexane-d12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05
Film contrast
43
University of Cologne 44
D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.05 (bulk contrast)
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
The Influence of Amphiphilic Polymers
University of Cologne 45
D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.05 (bulk contrast)
twater-uptake = (313±48) ms tradial growth = (1600±167) ms
The Influence of Amphiphilic Polymers
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D2O/NaCl – cyclohexane-d/h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.05 (film contrast)
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
The Influence of Amphiphilic Polymers
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D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.05 (film contrast)
tradial growth = (1725±138) ms
The Influence of Amphiphilic Polymers
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D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.10 (bulk contrast)
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
The Influence of Amphiphilic Polymers
University of Cologne 49
D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.10 (bulk contrast)
twater-uptake = (98±13) ms tradial growth = (6215±1436) ms
The Influence of Amphiphilic Polymers
University of Cologne 50
D2O/NaCl – cyclohexane-d/h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.10 (film contrast)
J. S. Pedersen, J Appl Crystallogr, 1994, 27, 595-608.
M. Kotlarchyk, S. H. Chen and J. S. Huang, Phys Rev A, 1983, 28, 508-511.
M. Gradzielski, D. Langevin, L. Magid and R. Strey, J Phys Chem-Us, 1995, 99, 13232-13238.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
T. Foster, T. Sottmann, R. Schweins and R. Strey, J Chem Phys, 2008, 128.
The Influence of Amphiphilic Polymers
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D2O/NaCl – cyclohexane-h12 – C10E5/PEB4.8-PEO4.8
e = 0.001, b=0.05, d = 0.10 (film contrast)
tradial growth = (5925±1876) ms
The Influence of Amphiphilic Polymers
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52
Theoretical background
T. Sottmann and R. Strey, J. Chem. Phys. 106, 8606 (1997)
Thermodynamic stability:
Structure size approximation:
Specific internal interface:
Droplet radius approximation:
Approximate structure size:
²TkB
VSa
/
)1(
c
cic
v
aVS ,/
iC
Ac
iC
A
c
c la
vR
,,
33
minmax//2 q