Supporting information for
The Synthesis and Self-Assembly of ABA Amphiphilic Block
Copolymers Containing Oligo(ethylene glycol) Methyl Ether
Methacrylate in Dilute Aqueous Solutions: Aggregate Morphologies,
Cloud Points and Stabilities
Simon J. Holder,a Geraldine G. Durand,a Chert-Tsun Yeoh,a Elodie Illi a, ,
Nicholas J. Hardyb and Tim H. Richardsonb
a
Functional Materials Group, School of Physical Sciences, University of Kent, Canterbury, Kent. CT2
7NH. UK. b Nanomaterials Engineering Group,, The University of Sheffield, Department of Physics &
Astronomy, Hicks Building, Hounsfield Road, Sheffield. S3 7RH. UK.
Page 2:
Determination of critical aggregation concentrations of dilute block copolymer
solutions by the Pyrene 1:3 ratio method.
Page 3:
Figure S1. Typical determination of the CMC by the Pyrene 1:3 ratio method: CAC
taken from the inflection point of a plot of the ratio I1/I3 against the log of the
concentration of the block copolymer (ABA13) in solution.
Page 4:
Figure S2. Molecular weight distribution curves for samples during the synthesis of
ABA1 illustrating evolution of molecular weight with time.
Figure S3. Typical molecular weight distribution curves for ,w-dibromopolystyrene
macroinitiator and resultant ABA POEGMA-PS-POEGMA block copolymer from
ATRP.
Page 4: Table S1. Molecular weight parameters and cloud points of the
poly[oligoethylene glycol methyl ether) methacrylate] samples used in the
determination of the lower critical solution temperatures.
Page 5: Figure S4. A) Overlay of the particle size distributions for ABA10 over 918
hrs. B) Plot of the particle size of the first distribution of aggregates (micelles)
versus the time for ABA10, ABA11 and ABA12.
Page 6:
Figure S5. Additional representative TEM images of various POEGMA-PSPOEGMA copolymer aggregate dispersions.

Corresponding author. Tel.: +44 1227 823547
E-mail address: S.J.Holder@kent.ac.uk.
1
Determination of critical aggregation concentrations of dilute block copolymer
solutions by the Pyrene 1:3 ratio method.
The method involves the use of pyrene, a hydrophobic fluorescence dye, which
exhibits different fluorescence characteristics depending upon the properties of the
solubilising medium. The pyrene fluorescence emission spectrum consists mainly of
five bands referred to as I1, I2…I5, from shorter to longer wavelength. Pyrene is
sensitive to the polarity of the solubilising medium and exhibits different fluorescence
behaviour in micellar and non-micellar solutions. Pyrene solubility in water is very
low (solubility in water at 25°C =2x10-6) and in the presence of micelles, pyrene is
preferentially solubilised into the interior of the hydrophobic regions of these
aggregates. Pyrene in water has only a very small absorption at 339nm which
increases substantially upon transfer to the less polar micellar domain.
Kalyanasundaran and Thomas demonstrated that the characteristic dependence of the
fluorescence vibrational fine structure of pyrene could be used to determine the
critical micellar concentration (CMC) of surfactant solutions. This is known as the
pyrene 1:3 ratio method. The vibrational fine structure changes as the transfer of
pyrene from a polar environment to a non polar one allow the symmetry forbidden
(0,0) band. Its change is described in terms of the ratio I1/I3, the intensities of the first
and the third bands in the pyrene fluorescence spectrum, respectively. The CMC
values can be obtained from the pyrene 1:3 ratio using two approaches 2, 3: from the
interseption of the rapidly varying part and the nearly horizontal part at high
concentration of the Pyrene 1:3 ratio plot; and from the inflection point of the Pyrene
1:3 ratio plots which is used for very low cmcs (typically below 1nM). The ratio I1/I3
(I1 at 373nm and I3 at 383nm) is dependent mainly on the polarity of the environment.
Below a certain concentration (e.g. C=5.62 x 10-7 gL-1 for ABA3) the ratio I1/I3 is
essentially constant and above this concentration, this intensity ratio increases with
increasing log C. This change in intensity reflects the onset of micelle formation and
the partitioning of the pyrene between the aqueous and micellar phases. For all
samples the CAC value was taken as the center of the sigmoid, the inflection point
from the plot of the I1/I3 ratio as a function of the logarithm of the copolymer
concentration, e.g. Figure S1.
2
0.74
Y1=A1
0.72
0.70
I1/I3 ratio
0.68
-Log (CMC)
0.66
0.64
(Xcmc, (A1+A2)/2)
0.62
0.60
0.58
0.56
Y2=A2
0.54
-10
-8
-6
-4
-2
0
Log (C)
Figure S1. Typical determination of the CMC by the Pyrene 1:3 ratio method: CAC
taken from the inflection point of a plot of the ratio I1/I3 against the log of the
concentration of the block copolymer (ABA13) in solution.
References
1. Kalyanasundaram, K.; Thomas. J. K. J. Am. Chem. Soc. 1977, 99, 2039–2044.
2. Aguiar J.; Carpena P.; Molina-Bolivar J.A.; Carnero Ruiz C. J. Coll Inter Sci 2003,
258, 116-122.
3. Zana R.; Levy H.; Kwetkat K. Langmuir 1997, 13, 402.
3
Figure S2. Molecular weight distribution curves for samples during the synthesis of
ABA1 illustrating evolution of molecular weight with time.
POEGMA(56)-PS(200)-POEGMA(56)
Figure S3. Typical molecular weight distribution curves for ,w-dibromopolystyrene
macroinitiator and resultant ABA POEGMA-PS-POEGMA block copolymer from
ATRP.
4
Table S1. Molecular weight parameters of poly[(oligoethylene glycol methyl ether)
methacrylate] studied and the cloud points measured at different concentrations.
POEGMA
samples
Mn by
GPC
DP by
GPC
Mw/Mn
1.52
Conc.
Solution
(wt %)
0.5
Cloud
point a
(oC)
63.9 ± 0.1
1
5,900
20
1
1
2
2
2
3
3
3
4
4
4
5
5
5
5,900
5,900
15,400
15,400
15,400
16,800
16,800
16,800
25,400
25,400
25,400
38,300
38,300
38,300
20
20
51
51
51
56
56
56
85
85
85
128
128
128
1.52
1.52
1.19
1.19
1.19
1.16
1.16
1.16
1.04
1.04
1.04
1.08
1.08
1.08
1
5
0.5
1
5
0.5
1
5
0.5
1
5
0.5
1
5
62.6 ± 0.1
61.7 ± 0.1
63.3 ± 0.1
62.3 ± 0.1
60.9 ± 0.1
62.9 ± 0.1
62.1 ± 0.1
60.3 ± 0.1
61.6 ± 0.1
60.9 ± 0.1
60.1 ± 0.1
61.5 ± 0.1
59.8 ± 0.1
60.0 ± 0.1
a
= Average of 3 measurements; error bars represent upper and lower temperatures
recorded.
5
60
Volume %
0.8
0.6
0.4
0.2
ABA10 / 26 POEGMA units
ABA11 / 37 POEGMA units
ABA12 / 56 POEGMA units
55
B
50
Particle Size of micelles (nm)
3hrs
24hrs
42hrs
264hrs
525hrs
918hrs
A
1.0
45
40
35
30
25
20
15
10
5
0.0
0
1
10
100
Particle size (nm)
1000
-1
0
1
2
3
4
5
6
7
Log (Time)
Figure S4. A) Overlay of the particle size distributions for ABA10 over 918 hrs.
B) Plot of the particle size of the first distribution of aggregates (micelles)
versus the time for ABA10, ABA11 and ABA12.
6
Figure S2: Additional representative TEM images of various POEGMA-PSPOEGMA copolymer aggregate aqueous dispersions.
ABA1, POEGMA16-PS75-POEGMA16
ABA3, POEGMA43-PS86-POEGMA43
ABA5, POEGMA79-PS75-POEGMA79
ABA8, POEGMA16-PS204-POEGMA16
ABA11, POEGMA37-PS204-POEGMA37
ABA14, POEGMA64-PS183-POEGMA64
7
ABA15, POEGMA80-PS200-POEGMA80
Figure S3: Representative TEM images of ABA8, POEGMA16-PS204-POEGMA16
copolymer micelles prepared at different concentrations.
..
ABA8, 0.01g dm-3
POEGMA16-PS204-POEGMA16
ABA8, 0.1g dmPOEGMA16-PS204-POEGMA16
8