Structure Characterization Measurement
The structures confirmation of surfmer AA-TX-100 and copolymer AMPS/ AA-TX-100 was
obtained by 1H-NMR. 1H-NMR spectra were carried out at room temperature with a 400 MHz
NMR spectrometer (Bruker, Switzerland) on samples to determine the structure of AA-TX-100
and whether AA-TX-100 units are incorporated into the polymer molecules.
Molecular Weight of Copolymer Characterization
Gel permeation chromatography (GPC) instrument (Waters Co., USA) was used to determine
the molecular weights and molecular weight distributions of copolymers. GPC analysis was
carried out with a Waters 515 HPLC pump equipped with a Waters 2414 refractive index
detector and three columns (Ultrahydrogel 2000, Ultrahydrogel 1000 and Ultrahydrogel 500)
using 0.1M NaNO3 aqueous solutions as the eluent with a flow of 0.5ml/min. All the
measurements were performed at 30oC, and the molecular weights of the copolymers were
calibrated with polyacrylamide standard samples (Mp: 900-11, 00,000 Da)
Procedures for Fluorescence Measurement
Steady-state fluorescence spectra were performed on a Hitachi F-4500 spectrofluorometer
(Hitachi, Ltd., Japan). All the measurements were carried out at ambient temperature. The
fluorescence spectra of probe pyrene in polymer solutions were detected by using a 337 nm
excitation wavelength, with a slit width of 2.5nm and in a scanning range of 350-450nm. The
polarity of microenvironment in polymer solution was estimated by using the ratio of the
intensities of the first vibronic peak (I1, 373nm) to that of the third vibronic peak (I3, 384nm) in
pyrene probe fluorescence spectrum. Polymer solutions with the desired pyrene concentration
(10-6 M) were prepared as follows: 0.5ml of 10-3 M pyrene solution was added in ethanol in a
100 ml volumetric flask, and a thin film of pyrene was formed at the bottom of the flask through
1
bubbling N2 to evaporate the solvent. Then 50ml polymer solutions were added. The solutions
were stirred at room temperature for 24h to reach the equilibrium of pyrene in the aqueous phase.
Characterization of surfmer AA-TX-100
The 1H-NMR spectra of surfmer AA-TX-100 in CDCl3 are shown in Figure 1: 0.71 (s, 9H,
alkyl –(CH3)3), 1.33 (s, 6H, alkyl -(CH3)2),1.69 (s, 2H, alkyl -CH2), 3.64 (m, 36H, -CH2CH2O- ),
4.11 (t, 2H, -O-CH2-CH2-), 4.31 (t, 2H, -CH2-O-CO-), 5.83 (m, H, CH2=CH-), 6.12 (m, H,
CH2=CH-), 6.40 (d, H, -CH= CH2), 6.81 (d, 2H, -CH in benzen ), 7.26 (t, 2H, -CH in benzen ).
Figure 1s. The 1H-NMR spectrum of surfmer AA-TX-100
Characterization of Copolymer AMPS/ AA-TX-100
The composition of copolymer was further analyzed and the degree of substitution for surfmer
AA-TX-100 units in copolymer AMPS/AA-TX-100 was determined according to the following
equations.
2
Ha+Hb=2×3y +3×3y =15y=Aa (1)
Hc+Hh+Hi+Hj+Hk+Hl=2y+y+2y+ x+2x +2×3x=5y+9x= Ab (2)
The equations are solved and got the final equation:
y
9A𝑎
Surfmer unit mol% = x = 15A
𝑏 −5A𝑎
× 100% (3)
Where Aa is the integral area for the alkyl -CH3 group in surfmer unit, Ab is the integral area
for alkyl -CH2, and –CH2-CH2- in polymer main chain and -CH3 group in AMPS unit. The 1HNMR spectra were shown in Figure 2-4.
Figure 2s. The 1H-NMR spectrum of AA-1
3
1
HNMR (400 MHz, CDCl3): 0.70 (a,b, alkyl -(CH3)3), 1.16～2.08 (c, h～m, alkyl -CH2, -CH2-
CH- in polymer main chain, -CH3 group in AMPS), 3.42(f,g,n, -CH2CH2O-, alkyl -CH2 group in
AMPS), 6.96 (e, -CH in benzen ), 7.40 (d, -CH in benzen ).
Surfmer unit mol% =
9 ∗ 15
× 100% = 1.025%
15 ∗ 883 − 5 ∗ 15
Figure 3s. The 1H-NMR spectrum of AA-2.5
1
HNMR (400 MHz, CDCl3): 0.70 (a,b, alkyl -(CH3)3), 1.16～2.08 (c, h～m, alkyl -CH2, -CH2-
CH- in polymer main chain, -CH3 group in AMPS), 3.39(f,g,n, -CH2CH2O-, alkyl -CH2 group in
AMPS), 6.94 (e, -CH in benzen ), 7.39 (d, -CH in benzen ).
Surfmer unit mol% =
9 ∗ 15
× 100% = 2.507%
15 ∗ 364 − 5 ∗ 15
4
Figure 4s. The 1H-NMR spectrum of AA-5
1
HNMR (400 MHz, CDCl3): 0.70 (a,b, alkyl -(CH3)3), 1.13～2.08 (c, h～m, alkyl -CH2, -CH2-
CH- in polymer main chain, -CH3 group in AMPS), 3.42(f,g,n, -CH2CH2O-, alkyl -CH2 group in
AMPS), 6.93 (e, -CH in benzen ), 7.41 (d, -CH in benzen ).
Surfmer unit mol% =
9 ∗ 15
× 100% = 4.972%
15 ∗ 186 − 5 ∗ 15
5
Figure 5s. The 1H-NMR spectrum of PAMPS
1
HNMR (400 MHz, CDCl3): 1.54 (a,c,d, -CH2- in polymer main chain, -CH3 group in AMPS),
2.07 (b, -CH- in polymer main chain), 3.38(e, -CH2 group in AMPS)
6
Results of GPC Test
Figure 6s. The GPC result of AA-1
7
Figure 7s. The GPC result of AA-2.5
8
9
Figure 8s. The GPC result of AA-5
10
Figure 9s. The GPC result of PAMPS
11
Synthesis Optimization of Copolymer AMPS/AA-TX-100 series
In Table 1.1s, the synthesis conditions of copolymer AA-1 were optimized. The effect of
initiator on the apparent viscosity of copolymer AA-1 was investigated and shown in entries 1～
5 showed that the copolymer could achieve the best apparent viscosity (461.6mPa.s) as the
amount of initiator was 0.4 mol%. In addition, the reaction temperature and reaction time for
copolymer AA-1 were both studied in entries 6～15. The results clearly showed that the apparent
viscosity of copolymer solution could reach to 491.1mPa.s as the reaction temperature was 50oC
and the reaction time was 4h.
TABLE 1.1s. Reaction conditions of copolymer AA-1
Reaction Conditions
Entry
Apparent
Viscosity
AA-TXInitiator(mol%)b Temperature(oC) Time(h)
100/AMPS
(mPa.s)a,b
1
0.01
0.2
45
24
358.3
2
0.01
0.4
45
24
461.6
3
0.01
0.6
45
24
432.1
4
0.01
0.8
45
24
304
5
0.01
1.2
45
24
277.6
6
0.01
0.4
30
24
358.3
12
7
0.01
0.4
40
24
366.7
8
0.01
0.4
50
24
496.3
9
0.01
0.4
55
24
315.3
10
0.01
0.4
60
24
300.1
11
0.01
0.4
50
12
491.1
12
0.01
0.4
50
8
505.3
13
0.01
0.4
50
6
497.7
14
0.01
0.4
50
4
491.1
15
0.01
0.4
50
2
386.7
In Table 1.2s, the synthesis conditions of copolymer AA-2.5 were optimized. The effect of
initiator on the apparent viscosity of copolymer AA-2.5 was investigated and shown in entries 1
～5 showed that the copolymer could achieve the best apparent viscosity (623.3mPa.s) as the
amount of initiator was 0.4 mol%. In addition, the reaction temperature and reaction time for
copolymer AA-2.5 were both studied in entries 6～15. The results clearly showed that the
apparent viscosity of copolymer solution could reach to 661.3mPa.s as the reaction temperature
was 50oC and the reaction time was 6h.
Table 1.2s Reaction conditions of copolymer AA-2.5
13
Reaction Conditions
Entry
Apparent
Viscosity
AA-TXb
Initiator(mol%)
o
Temperature( C) Time(h)
100/AMPS
(mPa.s)a,b
1
0.025
0.2
45
24
551.2
2
0.025
0.4
45
24
623.3
3
0.025
0.6
45
24
603.5
4
0.025
0.8
45
24
579.8
5
0.025
1.2
45
24
541.5
6
0.025
0.4
30
24
537.5
7
0.025
0.4
40
24
607.9
8
0.025
0.4
50
24
621.3
9
0.025
0.4
55
24
567.2
10
0.025
0.4
60
24
472.1
11
0.025
0.4
50
12
672.1
12
0.025
0.4
50
8
667.2
13
0.025
0.4
50
6
661.3
14
0.025
0.4
50
4
556.5
14
15
0.025
0.4
50
2
337.9
In Table 1.3s, the synthesis conditions of copolymer AA-5 were optimized. The effect of
initiator on the apparent viscosity of copolymer AA-5 was investigated and shown in entries 1～
5 showed that the copolymer could achieve the best apparent viscosity (557.1mPa.s) as the
amount of initiator was 0.4 mol%. In addition, the reaction temperature and reaction time for
copolymer AA-2.5 were both studied in entries 6～15. The results clearly showed that the
apparent viscosity of copolymer solution could reach to 661.3mPa.s as the reaction temperature
was 50oC and the reaction time was 6h.
Table 1.3s Reaction conditions of copolymer AA-5
Reaction Conditions
Entry
Apparent
Viscosity
AA-TXInitiator(mol%)b Temperature(oC) Time(h)
100/AMPS
(mPa.s)a,b
1
0.05
0.2
45
24
356.3
2
0.05
0.4
45
24
557.1
3
0.05
0.6
45
24
551.3
4
0.05
0.8
45
24
537.8
5
0.05
1.2
45
24
463.1
15
6
0.05
0.4
30
24
377.5
7
0.05
0.4
40
24
507.1
8
0.05
0.4
50
24
571.1
9
0.05
0.4
55
24
423.1
10
0.05
0.4
60
24
411.9
11
0.05
0.4
50
12
567.9
12
0.05
0.4
50
8
583.1
13
0.05
0.4
50
6
571.1
14
0.05
0.4
50
4
375.1
15
0.05
0.4
50
2
207.1
Synthesis of Partially Hydrolyzed Polyacrylamide (HPAM)
The copolymer was prepared by the aqueous free-radical copolymerization. AM, AA were
dissolved in deionized water in a 250ml flask, and the ratio of AM/AA was 7/3. Then NaHCO3
was used to control the pH value of the reaction solution at 7. The flask was purged with N2 for
half an hour. The reactant solution was then heated to 45oC in a tempering kettle under a nitrogen
atmosphere. (NH4)2S2O8-NaHSO3 initiator solution (0.3 wt%) was added to the solution and the
polymerization proceeded for 6h. The polymer was purified by precipitation with ethanol and
dried in vacuum oven at 40oC for 48h.
16
Critical Micelle Concentration of TX-100 and AA-TX-100
The critical micelle concentration (cmc) values of surfactant TX-100 and surfmer AA-TX-100
were determined by surface tension method. The surface tensions were measured by using TX500c spinning drop tensionmeter (Bowing, Stafford, TX) at 30 ± 0.1oC until the surface
tensions became constant values. The IFT was calculated and recorded by image acquisition
software with an image pick-up device. The cmc value was taken at the intersection of the linear
portions of the plots of the surface tension against the logarithm of the surfactant concentration.
In Figure 10s, the results show that AA-TX-100 is as good as TX-100 that can form micelles
at a very low concentration (at 10-4mol/L). It also indicates that the acrylate group introduced
into the structure of surfmer AA-TX-100 has a slight contribution to the cmc value of AA-TX100 since the cmc value of TX-100 is just a little smaller than the one of AA-TX-100.
41
TX-100
40
AA-TX-100
Surface tension (mN/m)
39
38
37
36
cmcTX-100: 2.980 mol/L
35
cmcAA-TX-100: 2.105 mol/L
34
33
32
31
1E-5
1E-4
1E-3
0.01
Concentration (mol/L)
Figure 10s. Surface tension vs logC plots for TX-100 and AA-TX-100
17
Effect of NaCl concentration on the aggregation of copolymers
The steady-state fluorescence test was carried out to reveal the aggregation behaviors of
copolymer AMPS/AA-TX-100 series at different NaCl concentration solutions at molecular
level. The variations of intensity ratio I1/I3 as a function of NaCl concentration for copolymer
AMPS/ AA-TX-100 series at 2000mg/L are plotted and shown in Figure 11s.
In AMPS/AA-TX-100 series, the ratios of I1/I3 are sharply increased with the increment of
NaCl concentration at the range of low NaCl concentration, which results from the
intermolecular hydrophobic association into intramolecular hydrophobic association that just can
form small aggregates and only a few pyrene molecules have opportunity to be distributed into a
nonaqueous environment. Finally, the ratio of I1/I3 has slight change at high NaCl concentration,
which indicates that the aggregations have already transformed from intermolecular hydrophobic
association to intramolecular hydrophobic association.
Generally, the intermolecular hydrophobic association will be increased with the increase in
the polarity of solution as the addition of salt.
18, 31
However, copolymer AMPS/AA-TX-100
series show different aggregation behaviors. This may be due to the high content of hydrophobic
microblock structure introduced into the copolymer chain. On one hand, copolymer with high
content of hydrophobic groups that are distributed in microblock manner along the polymer
backbone will be much more susceptible to form intramolecular aggregates and have a smaller
hydrodynamic volume in brine solution than the copolymer with low content of hydrophobic
units that are randomly distributed hydrophobic groups. On the other hand, the hydrophobic
interaction of surfmer AA-TX-100 is too strong that also can induce the copolymers with high
content hydrophobic groups easily to form intramolecular aggregates in brine solution.
18
1.55
1.50
1.45
I1/I3
1.40
1.35
AA-1
AA-2.5
AA-5
1.30
1.25
Copolymer Concentration: 2000mg/L
1.20
0
2000
4000
6000
8000
10000
NaCl Concentration(mg/L)
Figure 11s. Effect of NaCl concentration on the ratio of I1/I3
3.7 Effect of Temperature on Apparent Viscosity
The thermal stability of polymer solutions was measured by HAAKE MARS III rotational
rheometer. The correlation between apparent viscosity and temperature was obtained by
changing the temperature from 30 to 120oC at 7.34s-1 and the cylinder rotor PZ38 was used for
the test.
Figure 12s shows that copolymer AMPS/AA-TX-100 series have good thermal stability. The
apparent viscosities of copolymer AMPS/AA-TX-100 series are gradually reduced with raising
temperature. The copolymers show good retention of viscosities at high temperature. As the
temperature is 100oC, the viscosity retention rates of copolymer AA-1, AA-2.5, AA-5 are about
31.3%, 69.3%, 64.1%. These results indicate that the temperature plays a major role in
controlling the viscosity of copolymer solution. As the hydrophobic association is endothermic,
raising temperature will increase the motion of polymer molecules that transform hydrophobic
19
intramolecualr association into intermolecular association at low temperature, which can form
large hydrophobic microdomains to build up a high viscosity. However, the increasing motion of
polymer molecules also can lead to the reduction in connectivity of the network at high
temperature, resulting in breakage of network structure. Once the effect of connectivity loss in the
network surpasses the effect of hydrophobic microdomains, the apparent viscosity of polymer
solution begins to gradually reduce. Besides, anion group –SO32- in the polymer chain makes
contribute to enhance temperature resistance of copolymers as anion groups –SO32- is very stable
in high temperature. The combined interaction of these effects helps copolymer AMPS/AA-TX100 series achieve good thermal stability at high temperature.
1000
150
100
100
75
50
AA-1
AA-2.5
T in oC
AA-5
Polymer concentration: 5000mg/L
Temperature (oC)
Apparent viscosity (mPa.s)
125
25
10
0
0
500
1000
1500
2000
2500
Time (s-1)
FIGURE 12s. Effect of temperature on the viscosity of copolymer solution
20