Embed Size (px)
Citation preview
1
SUPPLEMENTARY INFORMATION
Precise control of grafting density in periodically grafted amphiphilic
copolymers: An alternate strategy to fine-tune the lamellar spacing in the
sub-10 nm regime
Ramkrishna Sarkara, E. Bhoje Gowdb, and S. Ramakrishnan*a
a Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-
560012, INDIA
b Material Sciences and Technology Division, CSIR-National Institute for Interdisciplinary
Science and Technology (CSIR-NIIST), Thiruvananthapuram – 695019, Kerala, INDIA
e-mail: [email protected]
Table of contents
Title Page number
Figure S1 2
Figure S2 3
Figure S3 4
Figure S4 4
Figure S5 5
Figure S6 5
Figure S7 6
Figure S8 7
Figure S9 8
Figure S10 9
Figure S11 9
Estimating the PEG550 layer thickness in PGACs
10
Figure S12 10
Figure S13 11
Synthesis of the monomers and intermediates
12-15
Electronic Supplementary Material (ESI) for Polymer Chemistry.This journal is © The Royal Society of Chemistry 2020
2
Figure S1: Stacked 1H NMR spectra of parent polymers (PEx) derived from propargyl bearing diol and diacid chlorides of variable lengths. The average degree of polymerization (DPn) of the polymers was estimated using the intensity of the CH2-OH end group peaks (at ~3.65 ppm), assuming that each chain, on an average, has a single CH2-OH end group; the values thus obtained are listed against each spectrum.
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
47
.73
4.6
6
4.1
6
0.9
9
2.0
0
0.3
3
4.0
7
3.9
4
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
45
.51
12
.44
0.9
9
3.9
6
2.0
0
0.2
2
3.9
6
4.0
0
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
50
.56
12
.52
1.0
0
3.5
9
2.0
0
0.4
0
3.5
7
3.8
58.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
64
.92
16
.64
0.9
0
4.1
0
2.0
0
0.3
4
3.7
7
4.0
8
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
-0.01
1.24
1.54
2.00
2.01
2.01
2.26
2.28
2.30
2.77
2.78
3.61
3.63
3.65
4.02
4.04
4.06
4.10
4.11
4.11
4.12
4.13
4.14
7.26
73
.27
12
.44
1.0
6
4.1
3
2.0
0
0.1
8
4.1
0
3.8
7
(PE0)
(PE4)
(PE8)
(PE12)
(PE18)
ba
ba
dc
dc
b aba
dc
dc
e
e
DPn = 12
DPn = 18
b aba
dc
dc
e
e
DPn = 10
b aba
dc
dc
e
e
DPn = 18
b aba
dc
dc
e
e
DPn = 22
End CH2OH
End CH2OH
End CH2OH
End CH2OH
End CH2OH
3
Figure S2: Stacked 1H spectra of PEG550 grafted copolymers (PEx-g-PEG550). The inset shows a Y-expanded region to reveal the complete disappearance of propargyl peak after alkyne-azide click reaction. The end-group signals are no longer visible since there is an overlap with the PEG550 segments; hence, the DPn values were not estimated. Since the click reactions is not expected to cause any chain degradation, the DP values could be taken to be the same as that of the parent polyesters.
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
52
.84
4.7
4
4.7
3
2.1
9
3.0
7
47
.30
2.1
8
4.0
7
3.9
9
2.0
0
0.9
2
2.62.8 ppm
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
55
.40
3.5
3
13
.63
4.0
8
2.0
3
3.2
8
58
.43
2.4
8
7.8
5
2.0
0
0.9
8
2.62.8 ppm
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
47
.81
3.6
7
13
.82
4.1
8
2.1
6
3.2
7
55
.23
2.5
8
8.1
4
2.0
0
1.0
1
2.62.72.8 ppm
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
58
.39
3.0
4
10
.97
3.6
6
2.5
4
3.4
4
59
.14
2.3
9
7.4
7
2.0
0
1.0
1
2.62.8 ppm
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm
0.01
0.08
1.26
1.41
1.61
1.63
1.64
2.28
2.30
2.32
3.33
3.40
3.66
4.05
4.06
4.08
4.11
4.12
4.13
4.49
4.51
4.52
7.29
7.43
7.49
82
.29
2.4
9
13
.79
4.4
5
2.1
6
3.3
7
56
.26
2.5
7
8.7
5
2.0
0
0.3
4
0.6
2
2.62.8 ppm
x8
x8
x8
x8
x8
(PE8-g-PEG550)
ba dc h
ef
g
ba
d c
h
ef
g
ba dc h
ef
g
a
d c
h
ef
g
ba dc h
ef
g
a
d c
h
ef
g
ba dc h
ef
g
a
d c
h
ef
g
ba dc
ef
g
a
dc
ef
g
(PE4-g-PEG550)
(PE0-g-PEG550)
(PE12-g-PEG550)
(PE18-g-PEG550)
4
Figure S3: Variation of melting temperature and associated enthalpies of parent polymers (PEx) with total number of backbone atoms. (Enthalpies are not normalized). Right side shows variation of melting temperature and associated enthalpies (normalized w.r.t weight fractions of the segments) in graft copolymers (PEx-g-PEG550) with total number of backbone atoms. An increment in melting and crystallization temperature was observed with increasing backbone chain length.
Figure S4: Variation of CH2 symmetric and asymmetric stretching frequencies with temperature for PEG550 grafted copolymers, PEx-g-PEG550. The onset temperature matches with DSC onset temperature of higher temperature peaks, confirming that the higher temperature peak is due to the HC segment. a=PE0-g-PEG550, b=PE8-g-PEG550, c=PE12-g-PEG550, d=PE18-g-PEG550.
-20 0 20 40 60 80
2850
2856
2916
2922
2928
Wa
ve
nu
mb
er
(cm
-1)
Temperature (oC)
CH2 sym. stretching
CH2 assym. stretching
38oC
a
-20 0 20 40 60 80 100
2850
2856
2916
2922
2928
Wav
e n
um
be
r (c
m-1)
Temperature (oC)
CH2 symm. stretching
CH2 asymm. stretching
69oC
d
-20 0 20 40 60 80
2850
2856
2916
2922
2928
Wa
ve
nu
mb
er
cm
-1
Temperatur (oC)
CH2 sym. stretching
CH2 asym. stretching
46oC
b
-20 0 20 40 60 80 100
2850
2856
2916
2922
2928
Wav
e n
um
be
r (c
m-1)
Temperature (oC)
CH2 sym. stretching
CH2 asym stretching
56oC
c
60
70
80
90
100
110
En
tha
lpy
(J
/g)
melting enthalpy
of parent polymer
39 42 45 48 51 54 5730
35
40
45
50
55
60
65
70
Me
ltin
g T
em
p. (o
C)
Number of backbone atom
Melting temp. of
Parent polymer
39 42 45 48 51 54 57
-20
0
20
40
60
80
Tem
pera
ture
(oC
)
Number of backbone atoms
Tm (HC)
Tm (PEG)
0
30
60
90
120
150
180
En
thalp
y (
J/g
)
Hm (HC)
Hm (PEG)
5
Figure S5: DSC stack plot of the PE18-g-PEG550 prepared via condensation of the diol bearing preinstalled PEG550 with corresponding acid chloride; and the polymer (PE18-g-PEG550) prepared by thermal alkyne-azide click reaction of the parent polymer (PE18) with PEG550 azide. The melting/crystallization temperatures as well as their associated enthalpies of these two polymers are not significantly different, confirming that the influence of regiospecificity is limited, if any.
Figure S6: Top: schematic depiction of long chain polyester where ester groups are shown to be accommodated within paraffinic lattice. [Adapted from reference 1] Bottom: Anticipated chain folding of a representative polymer, PE4-g-PEG550, where crystalline backbone contains ester groups at the middle.
PE4-g-PEG550
folding
Polymer chainfolding
Ester groups at the middle of hydrocarbon
Ester groups have been shown to pack in the crystalline paraffinic lattice formed by long alkylene segments
-10
-5
0
5
10
15Tm=71.69oC, Hm=67.3 J/g
Tc=62.64oC, Hc=69.36 J/g
Tm=0.79oC, Hm=12.3 J/g
Tc=-29.87oC, Hc=8.86 J/g
-40 -20 0 20 40 60 80
-10
0
10
20
30
Temperature (oC)
Tm=65.33oCHm=70.6 J/gTm=-1.46oC
Hm= 12.8 J/g
Tc=55.96oCHc=70.9 J/g
Tc=-27.93oCHc= 8.2 J/g
PE18-g-PEG550
PE18-g-PEG550- Preinstalled PEG550
Hea
tfl
ow
(mW
) en
do
up
6
Figure S7: Deconvoluted WAXS profiles of the graft copolymers (PEx-g-PEG550) recorded at lower temperature. Dotted lines provide visual guidelines; red lines denote HC peaks and blue denote PEG peaks. The crystalline PEG peak at 2θ ~23.5o is clearly revealed for PE0-g-PEG550, PE8-g-PEG550 and PE12-g-PEG550.
Inte
nsi
ty (
a.u
)
2θ (deg.)
PE4-g-PEG550% crystallinity - 48.2 % (-20oC)
PE8-g-PEG550% crystallinity - 57.9 % (-20oC)
PE12-g-PEG550% crystallinity
- 57.8 % (-20oC)
PE18-g-PEG550% crystallinity
- 46.1 % (-30oC)
16 18 20 22 24 26 28 30
PE0-g-PEG550% crystallinity - 35.5 % (-35oC)
7
Figure S8: Deconvoluted WAXS profiles of PE12-g-PEG550 recorded at temperature below (-20 oC, -10 oC) and above (10 oC, 30 oC) PEG melting. The crystalline peak at ~23.5 o (visually guided by black dotted line) disappears above melting temperature of PEG, resulting a reduction of ~23.6 o peak intensity as reflected by the intensity difference of the two peaks at ~21.5 o and ~23.6 o.
16 18 20 22 24 26 28 30
0
20
40
60
80
100
0
20
40
60
80
100
0
20
40
60
80
100
0
20
40
60
80
100
-20 oC
-10 oC
10 oC
30 oC
2θ (deg.)
Inte
nsi
ty(a
.u)
36.2
37.65
54.5
53.42
8
Figure S9: Stack plot of the SAXS profiles of various PEx-g-PEG550 samples recorded at 25°C; the
dashed line provides a guide to reveal the increase of d-spacing (decrease of q-value) as a function of
backbone segment length. The d-spacing was calculated based on the average of q values obtained
from the first and higher orders peaks. In the case of PE0-g-PEG550, the weaker set of peaks
corresponding to the longer d-spacing is used to estimate the increment per methylene unit (Figure 6);
this is based on the assumption that in this lamellar organization the backbone is in a crystalline lattice
adopting an extended all-trans conformation.
15
30
45
60
15
30
45
6015
30
45
60
1 2 3 4 5
20
40
60
80
20
40
60
PE8-g-PEG550
PE4-g-PEG550
PE0-g-PEG550
PE12-g-PEG550
PE18-g-PEG550
q(nm-1)
Inte
nsi
ty(A
.U)
d=8.03 nm
d=8.57 nm
d=9.24 nm
d=9.85 nm
d=10.24nm
9
Figure S10: Variable temperature SAXS profiles of PE8-g-PEG550. The sample was first cooled to -35°C and then heated to 45°C; at each temperature it was allowed to equilibrate for 5 min before data collection. Plot on the right depicts variation of the peak intensities with temperature; a drastic reduction in the intensity of the first order peak upon melting of PEG segments is observed, along with a small increase in the 2nd order peak.
Figure S11: Variable temperature SAXS profile of PE12-g-PEG550. The sample was first cooled to -35°C and then heated to 45°C; at each temperature it was allowed to equilibrate for 5 min before data collection. Plot on the right depicts variation of the peak intensities with temperature; a drastic reduction in the intensity of the first order peak upon melting of PEG segments is observed, along with a small increase in the 2nd order peak.
1 2 3 4 5 -40 -20 0 20 40 60
0
20
40
60
80
100
120
1st order
2nd order
3rd order
4th order
Temperature (oC)q (nm-1)
Inte
nsi
ty (A
.U)
Inte
nsi
ty (A
.U)
-35oC
-25oC
-15oC
-5oC
5oC
15oC
25oC
35oC
45oC
PE12-g-PEG550
PE12-g-PEG5501q 2q 3q 4q
1 2 3 4 5 -40 -20 0 20 40 60
0
20
40
60
80
100
1st order
2nd order
3rd order
4th order
Temperature (oC)q (nm-1)
Inte
nsi
ty (A
.U)
Inte
nsi
ty (A
.U)
-35oC
-25oC
-15oC
-5oC
5oC
15oC
25oC
35oC
45oCPE8-g-PEG5501q 2q 3q
PE8-g-PEG550
4q
10
Estimating the PEG550 layer thickness in PGACs based on earlier studies by Chandra et al.5
Figure S12: Variation of inter-lamellar spacing in PGACs bearing long crystallizable
hydrocarbon segment (20 backbone methylene), as function of PEG chain length. The
extrapolated value (3.8 nm) yielded folded backbone length which matches well with the
theoretically estimated values [adapted from reference5 ] .
Lamellar spacing of the PGAC, poly(icosylene itaconate), containing 20 methylene
hydrocarbon backbone and PEG550 as the pendant segment was 6.9 nm at room
temperature, which is above the melting temperature of PEG segment and below that of the
backbone HC segment. Contribution of backbone segment to the observed lamella is
estimated to be 3.8 nm by extrapolation; hence, the contribution of amorphous PEG550
segment to lamella can be calculated to be: (6.9-3.8) = 3.1 nm. This value matches reasonably
well with contribution of PEG550 segments to the lamellar spacing of 3.27 nm, in the present
study.
PII-PEG350
PII-PEG550
PII-PEG750
PII-TEG
No. of atoms in the PEG segment
11
Figure S13: SAXS profile of PE0-g-PEG550 at 25oC (cooled from melt). The two sets of peaks, one
marked in black and the other in red, reveal the formation of two types of lamella with inter-lamellar
spacings of 8.03 nm and 5.25 nm, respectively. The peaks marked in red are more intense and do not
vary in intensity as a function of temperature (see figure 5, in the main manuscript). The weaker set of
peaks (in black) corresponding to the longer d-spacing is used to estimate the increment per methylene
unit (Figure 6); this is based on the assumption that in this lamellar organization the backbone is in a
crystalline lattice adopting an extended all-trans conformation.
1 2 3 4 5
20
40
60
3
2
1
5432
Inte
ns
ity
(A
.U)
q(nm-1)
1
q Position q position
0.78 1 (1q) 1.196 1 (1)
1.55 1.987 (2q) 2.389 1.997 (2q)
2.389 3.063 (3q) 3.707 3.099 (3q)
3.111 3.99 (4q)
3.85 4.94 (5q)
Lamellar spacing= 8.03 nm Lamellar spacing= 5.25 nm
12
Synthesis of the monomers and intermediates
Scheme S1: Synthesis scheme of propargyl bearing diol
Diethyl-2-methyl-2propargylmalonate (2)
A 500 mL round bottom charged with 7 g sodium hydride (60 wt. % in mineral oil, 175.07
mmol) and 200 mL dry-distilled THF was added to it. 20.31 g (116.57 mmol) diethyl
methylmalonate was added dropwise to it while maintaining the temperature at 0 ˚C. The
reaction mixture was stirred continuously for 2 h at 0 ˚C. Subsequently, 20.85 (175.2 mmol)
propargyl bromide was added dropwise and reaction was continued at room temperature for
24 h. THF was removed using rotary evaporator and 200 mL ethyl acetate was added to it.
The organic layer containing product was washed twice (2 x 100 mL) with water and passed
through sodium sulphate. Finally, solvent was removed under reduced pressure to yield
product, which was distilled in Kugelrohr at 85 ̊ C under reduced pressure with a yield of 18.27
g colourless liquid product (74 % yield).
1H NMR (δ, CDCl3): 4.21 (m, 4H, -CH2CH3); 2.78 (d, 2H, -CH2CCH); 2.01 (t, 1H, -CH2CCH); 1.54
(s, 3H, -CH3); 1.25 (t, 6H, -CH2CH3)
2-Methyl-2-propargylmalonic acid (3)
To a 250 ml round bottom flask, 13.12 g (233.84 mmol) potassium hydroxide was added and
dissolved in minimum amount of water. 200 ml methanol was added to it. Subsequently, 8 g
(37.68 mmol) diethyl-2-methyl-2-propargylmalonate (2) was added and the reaction was
continued at 50 oC for 24 h. Subsequently, 50 mL water was added to it and methanol was
removed by rotary evaporation. pH of the solution made to ~4 by addition of HCl and product
was extracted in 150 mL (3 x 50 mL) ethyl acetate. The organic solvent was dried over sodium
NaH
THF+
KOH
Methanol
(1) (1) (2) (3)
+NaHCO3
DMSO
(3) (4)(6)
13
sulphate. Finally, removal of organic solvent under reduced pressure resulted 5.12 g solid
product with 87 % yield.
1H NMR (δ, DMSO-d6): 12.95 (s, 2H, -CO2H); 2.87 (t, 1H, -CH2CCH); 2.62 (d, 2H, -CH2CCH); 1.37
(s, 3H, -CH3)
Di (ω-hydroxypentadecanyl) 2- methyl-2- propargylmalonate (4)
2.5 g (16.23 mmol) 2-methyl-2propargylmalonic acid (3) and 8.72 g (103.8 mmol) sodium
bicarbonate were taken in 100 mL DMSO. 16 g (52.11mmol) 15-bromopentadecanol along
with catalytic amount potassium iodide were added to it. The resulted reaction mixture was
stirred at 40 ˚C for 4 days. 150 mL chloroform was added to it and DSMO was extracted in 450
mL (3 x 150 mL) 1 wt. % aqueous solution of lithium chloride. Organic layer was dried over
sodium sulfate and concentrated to yield final product. The crude product was first
recrystallized from methanol with 55 % yield (5.37 g)
1H NMR (δ, CDCl3): 4.11 {(m, 4H, -CO2CH2(CH2)13CH2OH)}X ; 3.63 {(t, 4H, HOCH2(CH2)13CH2- )};
2.78 (d, 2H, -CH2CCH); 2 (t, 1H, -CH2CCH); 1.54 (s, 3H, -CH3)
Scheme S2: Synthesis scheme of 15-bromo-1-pentadecanol
15-Bromopentadecanoic acid (5)
24 g (100 mmol) pentadecanolide were taken in a 500 ml round bottom flask. 200 ml 48%
aqueous hydrobromic acid was added to it. 20 ml concentrated sulfuric acid was slowly added
to it. The reaction mixture was refluxed for 48 h. Subsequently, product was extracted in 250
ml chloroform which was washed twice with water (2x100ml). The product containing organic
layer was passed through sodium and concentrated to obtain 29.8 g solid 15-bromo-1-
pentadecanoic acid with 93 % yield.
1H NMR (δ, CDCl3): 3.40 {(t, 2H, BrCH2(CH2)12CH2CO2H)}; 2.34 {(t, 2H, BrCH2(CH2)12CH2CO2H)};
1.85 {(m, 2H, BrCH2CH2(CH2)11CH2CO2H)}; 1.63 {(m, 2H, BrCH2 (CH2)12CH2CH2CO2H)}
(5) (6)
Water/ Reflux
HBr/H2SO4
THF
BH3.Me2S
14
15-Bromo-1-pentadecanol (6)
14 g (43.6 mmol) 15-bromopentadecanoic acid (5) was taken in 500 mL double neck round
bottom flask along with 200 mL THF. The solution was purged with nitrogen gas for 10 min.
5 g (65 mmol) borane dimethylsulfide was added dropwise to the solution at room
temperature with continuous nitrogen purging. The reaction mixture was stirred at room
temperature for overnight. 50 mL 4 (N) HCl was added to the mixture slowly and stirred for
2 h. Subsequently, THF was removed by rotary evaporation. 200 mL chloroform was added
to it and the organic solvent containing product was washed twice (2 x 100 mL) with water.
Finally, organic layer was passed through Na2SO4 and concentrated to yield 11.6 g (87 % yield)
product.
1H NMR (δ, CDCl3): 3.63 {t, 2H, HOCH2CH2(CH2)7CH2CH2Br}; 3.40 {t, 2H, HOCH2CH2(CH2)7CH2 -
CH2Br}; 1.85 {m, 2H, HOCH2CH2(CH2)7CH2CH2Br}; 1.56 {m, 2H, HOCH2CH2(CH2)7CH2CH2Br}
Scheme S3: Synthesis scheme of PE18-g-PEG550 with preinstalled PEG 550 segment
PEG550 grafted diol (7)
A reaction vessel was charged with 1 g (1.64 mmol) compound 4 and 1.18 g (1.95 mmol)
PEG550 azide along with 10 ml chloroform. 31 mg copper(I) iodide and 0.3 ml DIPEA was
added it. The reaction mixture was purged with nitrogen for 15 min and air tighten. The
reaction was carried out at 50 oC for 3 days. Subsequently centrifugation was carried out for
the removal of copper salt. The solution was concentrated and product was obtained by
reprecipitation from methanol
1H NMR (δ, CDCl3): 7.53 (1H, s , triazole ring); 4.49 {2H, t, Triazole-CH2CH2(CH2CH2O)yCH3}; 4.29
{4H , t, -O(O)CCH2CH2(CH2)11CH2CH2OH }; 3.62 {m, 50 H, Triazole-CH2CH2(CH2CH2O)yCH3}; 3.35
{s, 3 H, Triazole-CH2CH2(CH2CH2O)yCH3}; 3.32 {s, 2 H, -CH2Triazole-CH2CH2(CH2CH2O)yCH3}
+CuI/DIPEA
CHCl3
(4) (7)
+CuI/DIPEA
CHCl3
(7) (PE18-g-PEG550)
y~11, PEG550
15
The polymer was prepared using similar polymerization procedure to that of PEx.
PEG-550-tosylate monomethyl ether
2.5 g (62.5 mmol) sodium hydroxide was taken in 250 ml round bottom flux and dissolved in
minimum amount of water. 12 g (21.8 mmol) PEG 550 monomethyl ether and 150 ml THF was
then added to it. The contents were kept in ice bath and subsequently, 6.24 g (32.7 mmol)
tosyl chloride was added to it. The mixtures were stirred for 36 h at RT. THF was removed by
rotary evaporator and 150 ml DCM was added to it. DCM containing PEG tosylate was washed
twice (2 x 50 ml) with water. Finally, organic layer was passed through sodium sulphate and
concentrated under vacuum to yield product. Final product was obtained with 82 % (12.61 g)
yield.
1H NMR (δ, CDCl3): 7.76 (d, 2H, Ar); 7.31 (d, 2H, Ar); 4.13 (d,2H, CH3O-[CH2CH2O]n-CH2CH2-Ar-
CH3);3.62 (S, CH3O-[CH2CH2O]n-CH2CH2 -Ar-CH3); 3.35 (s,3H, CH3O-[CH2CH2O]n-CH2CH2-Ar-
CH3); 2.42 (s, 3H, CH3O-[CH2CH2O]n-CH2CH2-Ar-CH3)
PEG-550 monomethyl azide
5 g (7.09 mmol) PEG 550 tosylate and 1.84 g (28.36 mmol) sodium azide were taken in 100 ml
round bottom flask. 50 ml acetonitrile was added to it and the reaction was continued at
reflux for 3 days. Acetonitrile was removed using rotary evaporator and 70 ml chloroform was
added to it. The organic solvent containing product was washed twice (2x50 ml) with water
and passed through sodium sulphate. Finally, removal of solvent under reduced pressure
yielded 3.31 g product with 79 % yield.
1H NMR (δ, CDCl3): 3.62 (S, CH3O-[CH2CH2O]n-CH2CH2 -Ar-CH3); 3.35 (s,3H, CH3O-[CH2CH2O]n-
CH2CH2-Ar-CH3).
References
(1) M. G. Menges, J. Penelle, C. Le Fevere de Ten Hove, A. M. Jonas, K. Schmidt-Rohr, Macromolecules, 2007, 40, 8714-8725.
(2) S. Chanda, S. Ramakrishnan, Macromolecules, 2016, 49, 3254-3263.
![Efficient and Precise Interactive Hand Tracking Through oint ......Title Efficient and Precise Interactive Hand Tracking Through oint, Continuous Optimization of Pose and Correspondences6pt]Supplementary](https://img.pdfslide.us/doc/110x75/603ee8e59bc67d4df3303310/efficient-and-precise-interactive-hand-tracking-through-oint-title-efficient.jpg){kind=tracking}
