Thermodynamics, size, and dynamics
of zwitterionic dodecylphosphocholine and anionic sodium
dodecyl sulfate mixed micelles
Emilia Sikorskaa†, Dariusz Wyrzykowski,a Kosma Szutkowskib,c, Katarzyna Greberd, Emilia A.
Lubeckaa and Igor Zhukovc,e
a
Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
b
c
Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
Nanobiomedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań,
Poland
d
Faculty of Pharmacy, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416
Gdańsk, Poland
e
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-
106 Warsaw, Poland
†
Corresponding author: e-mail: emilia.sikorska@ug.edu.pl, phone: +48 58 5235080; fax: +48 058 5235012
1
Table 1S. Micellization parameters for the binary mixture of DPC and SDS in PBS at pH 7.4
as a function of temperature.
9:1 DPC/SDS
SDS=0.1
T /K
β
fSDS
fDPC
SDS
0.27
-1.67
0.41
0.89
0.27
-2.17
0.31
0.85
0.28
-2.26
0.31
0.84
0.31
-2.92
0.25
0.76
0.30
-3.12
0.22
0.76
0.29
-2.87
0.24
0.79
0.28
-2.82
0.23
0.80
5:1 DPC/SDS
SDS=0.17
T /K
cmcmix-exp
cmcmix-calc
β
fSDS
fDPC
SDS
293
0.68
1.34
0.39
-3.08
0.32
0.63
298
0.65
1.31
0.37
-3.32
0.27
0.63
303
0.66
1.27
0.37
-3.06
0.30
0.66
308
0.70
1.26
0.37
-2.79
0.33
0.68
313
0.74
1.37
0.35
-3.04
0.28
0.69
318
0.78
1.41
0.35
-2.96
0.29
0.70
323
0.85
1.46
0.34
-2.79
0.30
0.72
SDS denotes the mole fraction of SDS in the mixed micelles, β – the interaction parameter, whereas fSDS and fDPC
– the activity coefficients.
293
298
303
308
313
318
323
cmcmix1-exp
1.05
0.94
0.89
0.77
0.82
0.89
0.94
cmcmix-calc
1.39
1.33
1.30
1.29
1.38
1.41
1.46
2
Table 2S. Hydrodynamic parameters of the DPC-containing micelles defined with DOSY
spectroscopy.
Micelle
Dtr·10-11 /m2 s-1 a
Rh /Å b
T=293 K
DPC
9:1 DPC/SDS
5:1 DPC/SDS
6.60±0.16
6.14±0.05
5.92±0.03
DPC
9:1 DPC/SDS
5:1 DPC/SDS
8.22±0.04
7.94±0.08
7.88±0.05
DPC
9:1 DPC/SDS
5:1 DPC/SDS
10.69±0.12
10.22±0.04
10.13±0.05
32
35
36
T=303 K
34
35
35
T=313 K
a
Translational diffusion coefficient extracted from DPFGDSTE data;
b
Hydrodynamic radius calculated with Stokes-Einstein equation.
33
35
35
3
Figure 1S. Surface tension vs. log C plots of a DPC, b 9:1 DPC/SDS and c 5:1 DPC/SDS
micelles.
4
Figure 2S. Comparison of the experimentally obtained cmc1 data of the DPC/SDS mixed
micelles and the corresponding data calculated according to Clint’s model.
5
Figure 3S. FT PGSE analysis of DPFGDSTE experiment performed for DPC-containing
micelles at three different temperature: 273, 303 and 313 K. The signal corresponding to
choline methyl groups (3.23 ppm) was used to measure the surfactant signal attenuation. The
extracted values of translational diffusion coefficients correspond to Rh of the micelles in the
32-36 Å range.
6
Figure 4S. Comparison of the 1H spectra of DPC and the 5:1 DPC/SDS mixed micelles (pD
7.4, 303K). The total concentrations of the surfactants were fixed at 150 mM.
7
Figure 5S. 1H longitudinal relaxation times (T1) in pure a DPC, b 9:1 DPC/SDS and c 5:1
DPC/SDS micelles at 293K (black bars), 303K (gray bars) and 313K (white bars).
8
Figure 6S. Example of a T2 decay curve (H1 protons of DPC) as fitted by a bi-exponential
function.
9
Figure 7S. 1H transverse relaxation times (T2) in pure a DPC, b 9:1 DPC/SDS and c 5:1
DPC/SDS micelles at 293K (black bars), 303K (gray bars) and 313K (white bars). The
weighting factors with the standard deviations of fast and slow T2 relaxation times are given
close to appropriate bars.
10