Supporting Information
Synthesis of Amphiphilic Copolymer Brushes Possessing Alternating
Poly(methyl methacrylate) and Poly(N-isopropylacrylamide) Grafts
via a Combination of ATRP and Click Chemistry
Jun Yin, Zhishen Ge, Hao Liu, and Shiyong Liu*
CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and
Engineering, Hefei National Laboratory for Physical Sciences at the Microscale,
University of Science and Technology of China, Hefei, Anhui 230026, China
1
Experimental Section
Synthetic schemes employed for the preparation of N-[2-(2-bromoisobutyryloxy)ethyl]maleimide (BIBEMI) and 4-vinylbenzyl azide (VBA) were shown in Scheme
S1.1,2
Synthesis of HEBAA. Maleic anhydride (19.62 g, 0.2 mol) and 2-aminoethanol
(12.22 g, 0.2 mol) were dissolved in 30 mL of acetone, respectively. The reaction took
place under ice water, and both of the acetone solutions were added to a three-neck
bottle which contained 100 mL of acetone. The solutions were added slowly and the
whole time took about 2 h, then the reaction system was allowed to stir for another 2 h.
After all solvents were removed, the crude product was obtained and used without
further purification for later synthesis. 1H NMR (CDCl3, δ, ppm, TMS): 6.46 (1H,
-CH=CHCONH-), 6.25 (1H, HOOCCH=CH-), 3.5 (2H, HOCH2-), and 3.33 (2H,
-CH2NH-).
Synthesis of AEMI. HEBAA (6.36 g, 40 mmol) was added to 40 g acetic anhydride
and the reaction temperature was heated to 60 oC, after the solid was dissolved in the
solution, sodium acetate (1.97 g, 24 mmol) was added to the solution with vigorous
stirring, and the solution turned to dark brown. After 4 h, most of the acetic anhydride
was moved by vacuum and the residue was washed by a mixture of acetone and ethyl
ether (1:5 v/v) for 3 times. The crude product was recrystallized from ethyl ether to
give a solid (yield: ~60%). 1H NMR (CDCl3, δ, ppm, TMS): 6.74 (2H,
-COCH=CHCO-), 4.23 (2H, -COOCH2CH2-), 3.8 (2H, -COOCH2CH2-), 2.0 (3H,
CH3COO-).
Synthesis of HEMI. AEMI (3.0 g, 16.4 mmol), TsOH (0.312 g, 1.64 mmol) was
dissolved in 15 mL mixture of methanol and water (5:1 v/v). The reaction mixture
was allowed to reflux for 72 h. After all solvents moved by vacuum, the residue was
dissolved in CH2Cl2 and washed with saturated NaHCO3 solution to remove the
excess TsOH. The crude product was purified by silica gel column chromatography
using n-hexane/ethyl acetate (1:2 v/v) as the eluent to give HEMI as a solid (1.55 g,
yield: 51.7%). 1H NMR (CDCl3, δ, ppm, TMS): 6.74 (2H, -COCH=CHCO-), 3.77
(2H, HOCH2CH2-), 3.71 (2H, HOCH2CH2-), 2.1 (1H, HOCH2-).
2
Synthesis of BIBEMI. The maleimide ATRP initiator was prepared by the
esterification of HEMI with 2-bromoisobutyryl bromide. A 50 mL round-bottom flask
was charged with HEMI (1.55 g, 11 mmol), TEA (1.31 g, 12.9 mmol), and dry
CH2Cl2 (20 mL). The mixture was cooled to 0 oC in an ice-water bath, and
2-bromoisobutyryl bromide (1.64 mL, 12.9 mmol) in 5 mL of CH2Cl2 was added
dropwise over 1 h. Then the reaction mixture was stirred at room temperature for
another 5 h. After removing the insoluble salts by suction filtration, the filtrate was
concentrated and further purified by silica gel column chromatography using
n-hexane/ethyl acetate (5:1 v/v) as the eluent. After removing all the solvents, the
product was obtained as a liquid (2.69 g, yield: 84.6%). 1H NMR (CDCl3, δ, ppm,
TMS): 6.74 (s, 2H, -COCH=CHCO-), 4.36 (t, 2H, -COOCH2CH2-), 3.88 (t, 2H,
-COOCH2CH2-), 1.92 (s, 6H, -C(CH3)2Br).
Synthesis of 4-Vinylbenzyl Azide (VBA). 4-Vinylbenzyl chloride (5.0 g, 33 mmol)
was added to a solution of sodium azide (4.26 g, 66 mmol) in 20 mL of DMF, and the
reaction mixture was stirred for 12 h at room temperature. Then 100 mL of CH2Cl2
was added and the solution was washed with water (3  50 mL) to remove the excess
NaN3 and DMF. The organic layers were dried over anhydrous MgSO4, and CH2Cl2
was removed using a rotary evaporator. The product was obtained as a yellow liquid
(5.09 g, yield: 97%). 1H NMR (CDCl3, δ, ppm, TMS): 7.28-7.46 (4H, phenyl), 6.73
(1H, CH2=CH-), 5.29 and 5.79 (2H, CH2=CH-), 4.33 (2H, N3CH2-).
References
1. Deng, G. H.; Chen, Y. M. Macromolecules 2004, 37, 18-26.
2. Kim, Y. A.; Sharon, A.; Chu, C. K.; Rais, R. H.; Al Safarjalani, O. N.; Naguib, F. N.
M.; el Kouni, M. H. Biochem Pharmacol 2007, 73, 1558-1572.
3
O
2-aminoethanol
1)
O
O
O
O
O
O
N
(CH3CO)2O
OH HN
NaOCOCH3
acetone
O
OH
O
HEBAA
AEMI
TsOH
CH3OH/H2O
O
Br
O
N
O
Br
O
O
O
N
TEA, CH2Cl2
O
OH
Br
BIBEMI
HEMI
2)
NaN3
DMF
N3
Cl
VBC
VBA
Scheme S1. Reaction schemes employed for the preparation of (1) N-[2-(2bromoisobutyryloxy)ethyl]maleimide (BIBEMI) and (2) 4-vinylbenzyl azide (VBA).
4
O
c
b
a
b
N
H
a
OH
d
OH
d
c
O
a)
O
O
a
d
c
a
N
O
b
d
b
c
O
b)
O
b
a
a
OH d
N
c+b
c
O
d
c)
d
O
Br
b
a
N
a
O
c
d
O
O
c
b
d)
7
6
5
4
 / ppm
3
2
1
0
Figure S1. 1H NMR spectra of (a) HEBAA in DMSO-d6, (b) AEMI, (c) HEMI, and
(d) BIBEMI in CDCl3.
5
a
H
f
cH
Hb
d
d e
e
b
f
a
N3
c
8
7
6
 / ppm
5
4
Figure S2. 1H NMR spectrum recorded for 4-vinylbenzyl azide (VBA) in CDCl3.
6