Electronic Supplementary Material (ESI) for Physical Chemistry Chemical Physics.
This journal is © the Owner Societies 2016
Electronic Supplementary Information
Micelle formation of a non-ionic surfactant in non-aqueous molecular
solvents and protic ionic liquids (PILs)
Emmy C. Wijaya,ab Frances Separovic,a Calum J. Drummondc and Tamar L. Greavesc*
75
surface tension (mN/m)
70
65
60
55
50
45
40
35
30
-5
-4.8
-4.6
-4.4
-4.2
-4
-3.8
-3.6
-3.4
-3.2
-3
log C12E6 concentration (M)
Figure S1. Change in surface tension with different C12E6 concentrations in water
surface tension (mN/m)
36
35
34
33
32
31
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
log C12E6 concentration (M)
Figure S2. Change in surface tension with different C12E6 concentrations in 1-amino-2-propanol
1
surface tension (mN/m)
36
35
34
33
32
31
30
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
log C12E6 concentration (M)
Figure S3. Change in surface tension with different C12E6 concentrations in 2-amino-1-propanol
44
42
40
38
36
Surface tension (mN/m)
46
34
32
30
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
log (C12E6) concentration (M)
Figure S4. Change in surface tension with different C12E6 concentrations in 3-amino-1-propanol
2
Surface tension (mN/m)
44
42
40
38
36
34
32
log (C12E6) concentration (M)
-2
-1.6
-1.2
-0.8
-0.4
0
Figure S5. Change in surface tension with different C12E6 concentrations in 4-amino-1-butanol
Surface tension (mN/m)
46
44
42
40
38
36
34
32
30
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
log C12E6 concentration (M)
-0.5
0.0
Figure S6. Change in surface tension with different C12E6 concentrations in diethylene glycol
3
surface tension (mN/m)
37
36
35
34
33
32
-1
-0.8
-0.4
log-0.6
(C12E6) concentration
(M)-0.2
0
0.2
Figure S7. Change in surface tension with different C12E6 concentrations in diethylene triamine
surafe tension (mN/m)
46
44
42
40
38
36
34
32
30
-2.2
-1.8
-1.4
-1
-0.6
-0.2
0.2
log (C12E6) concentration (M)
Figure S8. Change in surface tension with different C12E6 concentrations in triethanolamine
4
surface tension (mN/m)
44
42
40
38
36
34
32
30
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
log (C12E6) concentration (M)
Figure S9. Change in surface tension with different C12E6 concentrations in triethylene glycol
surface tension (mN/m)
46
44
42
40
38
36
34
32
30
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
log (C12E6) concentration (M)
Figure S10. Change in surface tension with different C12E6 concentrations in triethylene tetramine
5
surface tension (mN/m)
42
40
38
36
34
32
30
-3
-2.5
-2
-1.5
-1
log (C12E6) concentration (M)
-0.5
0
Figure S11. Change in surface tension with different C12E6 concentrations in ethylammonium formate
(EAF)
surface tension (mN/m)
47
45
43
41
39
37
35
-4
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
log (C12E6) concentration (M)
Figure S12. Change in surface tension with different C12E6 concentrations in ethylammonium nitrate
(EAN)
6
_-* 70_-
surface tension (mN/m)
_-* 65__-* 60__-* 55__-* 50__-* 45__-* 40__-* 35__-* 30__-* 25__-* 20_-* 5.0_- -* 4.5_- -* 4.0_- -* 3.5_- -* 3.0_- -* 2.5_- -* 2.0_- -* 1.5_- -* 1.0_log (C12E6) concentration (M)
Figure S13. Change in surface tension with different C12E6 concentrations in ethanolammonium
formate (EOAF)
surface tension (mN/m)
70
65
60
55
50
45
40
35
30
25
-8
-7
-6
-5
-4
-3
log (C12E6) concentration (M)
-2
-1
0
Figure S14. Change in surface tension with different C12E6 concentrations in ethanolammonium
nitrate (EOAN)
7
Micelle scattering models
Coreshell spherical model
The spherical shape is the simplest form of micelles, which is usually found at low amphiphile
concentrations. The coreshell spherical model was used in this study due to the difference between
SLD core and SLD shell, and between SLD shell and SLD solvent. It provides a form factor, 𝑃(𝑞), and is
expressed by Eg 1 below,
𝑃(𝑞) =
[
[sin (𝑞𝑟𝑐) ‒ 𝑞𝑟𝑐 cos (𝑞𝑟𝑐)]
[sin (𝑞𝑟𝑠) ‒ 𝑞𝑟𝑐 cos (𝑞𝑟𝑠)]
𝑠𝑐𝑎𝑙𝑒
3𝑉𝑐(𝜌𝑐 ‒ 𝜌𝑠)
+ 3𝑉𝑠(𝜌𝑠 ‒ 𝜌𝑠𝑜𝑙𝑣)
𝑉𝑠
(𝑞𝑟 )3
(𝑞𝑟 )3
𝑐
𝑠
]
2
+ 𝑏𝑘𝑔
(1)
where 𝑠𝑐𝑎𝑙𝑒 is a scaling factor, 𝑉𝑠 is the volume of the outer shell, 𝑉𝑠 is the volume of the core, 𝑟𝑠 is
the radius of the shell, 𝑟𝑐 is the radius of the core (the shell thickness is 𝑟𝑠-𝑟𝑐), 𝜌𝑐 is the SLD of the core,
𝜌𝑠 is the SLD of the shell, 𝜌𝑠𝑜𝑙𝑣 is the solvent SLD, and 𝑏𝑘𝑔 is the background level.
SLD is calculated by equation
𝑛
𝜌=
∑𝑧 𝑟 /𝑉
𝑖 𝑒
𝑚
𝑖
where 𝑟𝑒 = 2.81 × 10
‒ 13
cm, which is the classical radius of the electron, 𝑧𝑖 is the atomic number of the
𝑖th atom in the molecular volume 𝑉𝑚. SLD core was calculated to be 7.92x10-6
Solvent SLDs were obtained from the SLD calculator provided in SASview software, by simply input the
chemical formula and the corresponding density. SLD solvents calculated for all solvents used in this
fitting are provided in Table S1 below.
Table S1. The chemical formula, density and SLD of solvents used in micelle fitting
Solvent
water
ethylene glycol
diethylene glycol
triethylene glycol
3-amino-1-propanol
triethanolamine
2-amino-2-ethyl-1,3-propanediol
ethylammonium nitrate
Chemical
formula
H2 O
C 2 H6 O2
C4H10O3
C6H14O4
C3H9NO
C6H15NO3
C5H13NO2
C 2 H8 N 2 O3
Density
(g/mL)
1
1.1132
1.118
1.1255
0.982
1.124
1.099
1.216
SLD solvent
9.47x10-06
1.04 x10-05
1.04 x10-05
1.05 x10-05
9.35 x10-06
1.05 x10-05
1.04 x10-05
1.11 x10-05
8
ethylammonium formate
ethanolammonium nitrate
ethanolammonium formate
C3H9NO2
C 2 H8 N 2 O4
C3H9NO3
1.039
1.265
1.184
9.71 x10-06
1.15 x10-05
1.09 x10-05
Ellipsoid model
The scattering for ellipsoids with radii 𝑅𝑎, 𝑅𝑎 and 𝑅𝑏 is shown Equations 2-4 below.
𝑃(𝑞,𝛼) =
𝑓(𝑞) =
𝑠𝑐𝑎𝑙𝑒 2
𝑓 (𝑞) + 𝑏𝑘𝑔
𝑉
(2)
3(∆𝜌)𝑉(𝑠𝑖𝑛[𝑞𝑟(𝑅𝑎,𝑅𝑏,𝛼)] ‒ 𝑞𝑟 𝑐𝑜𝑠[𝑞𝑟(𝑅𝑎,𝑅𝑏,𝛼)]
(3)
[𝑞𝑟(𝑅𝑎,𝑅𝑏,𝛼)]3
2
2
2
2
𝑟(𝑅𝑎,𝑅𝑏,𝛼) = [𝑅𝑏 𝑠𝑖𝑛 𝛼 + 𝑅𝑏 𝑐𝑜𝑠 𝛼]
1
2
(4)
𝛼 is the angle between the axis of the ellipsoid and the q-vector, 𝑉 is the volume of the ellipsoid, 𝑅𝑎is
the radius along the rotation axis of the ellipsoid, 𝑅𝑎 is the radius perpendicular to the rotation axis of
the ellipsoid, and ∆ρ is the SLD difference between the scatterer and the solvent.
Coreshell ellipsoid mode
This model provides the form factor, 𝑃(𝑞), for a core shell ellipsoid.
The form factor is calculated by using Equation 5-7 below,
𝑠𝑐𝑎𝑙𝑒
𝑃(𝑞) =
𝑉𝑠
1
∫|𝐹(𝑞,𝑟
𝑚𝑖𝑛,𝑟𝑚𝑎𝑗,𝛼
|2𝑑𝛼 + 𝑏𝑘𝑔
(5)
0
|𝐹(𝑞,𝑟𝑚𝑖𝑛,𝑟𝑚𝑎𝑗,𝛼| = 𝑉∆𝜌 ×
2 2
2
3𝑗1(𝑢)
( )
𝑢 = 𝑞[𝑟𝑚𝑎𝑗 𝛼 + 𝑟𝑚𝑖𝑛 (1 ‒ 𝛼
𝑢
2
)]
1
2
(6)
(7)
where 𝑟𝑚𝑖𝑛 is the equatorial outer radius, 𝑟𝑚𝑎𝑗 is the polar outer radius, and 𝑗1(𝑢) = (𝑠𝑖𝑛𝑥 ‒ 𝑥𝑐𝑜𝑠𝑥)/𝑥
2
9
10
Calculation of aggregation number
Volume of micellar core was calculated by
𝑉𝑐ℎ𝑎𝑖𝑛 = (27.4 + 26.9𝑛) Å3
where 𝑛 is the number of carbon atoms in the alkyl chain, in this case 𝑛 = 12
3
For C12E6 amphiphiles, 𝑉𝑐ℎ𝑎𝑖𝑛was calculated to be 350.2 Å
Number of aggregation (𝑁𝑎𝑔𝑔) was calculated by
𝑉𝑚𝑖𝑐𝑒𝑙𝑙𝑒
𝑉𝑐ℎ𝑎𝑖𝑛
where volume of micelle (𝑉𝑚𝑖𝑐𝑒𝑙𝑙𝑒) was calculated from the dimensions obtained from fitting.
Table S2. Shell SLD values obtained from the fitting
Solvent
water
ethylene glycol
[C12E6] (M)
Shell SLD
4.6 x10-3
9.6x10-6
2.5 x10
-1
9.9x10-6
1.4 x10
-1
1
3-amino-1-propanol
1
1.1x10-5
diethylene glycol
8.8 x10
1.5
1.1x10-5
triethylene glycol
7.2 x10-1
8.9x10-6
1.5
1.1x10-5
-1
1.0x10-5
triethanolamine
1
-
2-amino-2-ethyl-1,3pronanediol
5
1.0x10-5
EAN
EAF
10
1.0x10-5
8.5 x10
-2
1.7x10-5
2.1 x10
-1
1.1x10-5
3.6 x10-2
1.4x10-5
9.0 x10-2
1.0x10-5
0.5
1.5x10-5
11
0.007
0.00455 M
Intensity
0.006
0.246 M
0.005
0.004
0.003
0.002
0.001
0
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
q (Å-1)
Figure S15. Fitted SAXS profiles for 0.00455 and 0.246 M C12E6 in water. Circles and diamonds show
experimental data and solid lines shows fits to coreshell spherical model with no structure factor and
hardsphere structure factor, respectively.
Intensity
0.09
0.08
0.135 M
0.07
1M
0.06
0.05
0.04
0.03
0.02
0.01
0
0
0.05
0.1
0.15
0.2
q (Å-1)
0.25
0.3
0.35
0.4
0.45
Figure S16. Fitted SAXS profiles for 0.135 and 1 M C12E6 in ethylene glycol. Circles and diamonds show
experimental data and solid lines shows fits to ellipsoid model with no structure factor and hardsphere
structure factor, respectively.
12
0.009
0.008
Intensity
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0
0
0.1
0.2
0.3
0.4
q (Å-1)
Figure S17. Fitted SAXS profiles for 1 M C12E6 in 3-amino-1-propanol. Circles show experimental data
and solid line shows fits to coreshell spherical model with hardsphere structure factor.
0.03
0.8845 M
0.025
Intensity
1.5 M
0.02
0.015
0.01
0.005
0
0
0.05
0.1
0.15
0.2
q (Å-1)
0.25
0.3
0.35
0.4
0.45
Figure S18. Fitted SAXS profiles for 0.8845 and 1.5 M C12E6 in diethylene glycol. Circles and diamonds
show experimental data and solid lines shows fits to coreshell spherical model with hardsphere
structure factor.
13
0.03
0.718 M
Intensity
0.025
1.5 M
0.02
0.015
0.01
0.005
0
0
0.05
0.1
0.15
q (Å-1)0.2
0.25
0.3
0.35
0.4
Figure S19. Fitted SAXS profiles for 0.718 and 1.5 M% C12E6 in triethylene glycol. Circles and diamonds
show experimental data and solid lines shows fits to coreshell ellipsoid model with no structure factor
and hardsphere structure factor, respectively.
0.1
0.09
Intesnity
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
q (Å-1)
Figure S20. Fitted SAXS profiles for 1 M C12E6 in triethanolamine. Circles show experimental data and
solid lines shows fits to ellipsoid model with no structure factor.
14
0.035
5M
Intensity
0.03
10 M
0.025
0.02
0.015
0.01
0.005
0
0
0.05
0.1
0.15
0.2
q (Å-1)
0.25
0.3
0.35
0.4
Figure S21. Fitted SAXS profiles for 5 and 10 M C12E6 in 2-amino-2-ethyl-1,3-propanediol. Circles and
diamonds show experimental data and solid lines shows fits to coreshell spherical model with no
structure factor and hardsphere structure factor, respectively.
0.14
0.0849 M
Intensity
0.12
0.212 M
0.1
0.08
0.06
0.04
0.02
0
0
0.05
0.1
0.15
0.2
0.25
q (Å-1)
0.3
0.35
0.4
Figure S22. Fitted SAXS profiles for 0.0849 and 0.212 M C12E6 in ethylammonium nitrate (EAN). Circles
and diamonds show experimental data and solid lines shows fits to coreshell spherical model with no
structure factor and hardsphere structure factor, respectively.
15
0.06
Intensity
0.05
0.04
0.03
0.02
0.01
0
0
0.05
0.1
0.15
q (Å-1)
0.2
0.25
0.3
0.35
0.4
Figure S23. Fitted SAXS profiles for 0.5 M C12E6 in ethylammonium formate (EAF). Circles, diamonds,
and squares show experimental data and solid lines shows fits to coreshell ellipsoid model with no
structure factor.
16