Supporting Information for:
Synthesis and Characterization of two Classes of new Hyperstar Polymers Bearing
Hyperbranched Cores Grafted with Linear Arms
Frank Däbritz, Albena Lederer, Hartmut Komber, Brigitte Voit*
Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, D-01069 Dresden, Germany.
* contact: -49 351 4658 591, email: voit@ipfdd.de
Analysis
GC-MS was performed on a 6890N GC/5973N MSD system (Agilent Technologies) by
means of either EI- or CI-ionization. For separation a silica capillary column Durabond 35
MS (35% phenyl-methylpolysiloxane, J&W Scientific) was used with a stream of 1 mL/min
of Helium. Elemental analyses were performed on a 3000 Euro Vector CHNSO (Hekatech).
Monomers
2-[(tert-Butyl-dimethyl-silyloxy)-1-methylethyl]-oxazoline: (OSi)Oxa
2
1
N
O
9
3
5
4
8
O
6a/b
Si
7a/b
The synthesis was performed in accordance to the literature for introduction of silylprotecting groups.[1] Under argon atmosphere dried 2-[1-(hydroxymethyl)ethyl]-oxazoline
((OH)Oxa, 58.3 g, 47.0 mL, 451.5 mmol), dried Et3N (50.3 g, 69.2 mL, 496.7 mmol), N,Ndimethylaminopyridine (27.6 g, 225.8 mmol) and tert-butyldimethylsilyl chloride (74.9 g,
496.7 mmol) were provided in CH2Cl2 (0.8 L) and stirred under reflux for 24 h. After
filtration, evaporation of the solvent under vacuum, purification via column chromatographie
on silica gel with EtOAc:THF (gradient: 1:0-3:1) and subsequent distillation over CaH2 at
75 °C/0.04 Torr (OSi)Oxa was obtained in 50% yield (55.2 g, 226.6 mmol) as a colourless
liquid.
1
H NMR (500.13 MHz, DMSO-d6): δ (ppm) = 4.14 (t, 3JHH = 9.5 Hz, 2H, H-2), 3.73 (dd,
2
JHH = 9.8 Hz, 3JHH = 5.8 Hz, 1H, H-6a), 3.68 (t, 3JHH = 9.7 Hz, 2H, H-1), 3.58 (dd, 2JHH =
9.8 Hz, 3JHH = 6.8 Hz, 1H, H-6b), 2.53 (sxt, 3JHH = 7.0 Hz, H-4), 1.08 (d, 3JHH = 7.0 Hz, 3H,
H-5), 0.85 (s, 9H, H-9), 0.022 and 0.022 (two s, 6H, H-7a/7b).
C NMR (125.75 MHz, DMSO-d6): δ (ppm) = 168.01 (C-3), 66.48 (C-2), 64.97 (C-6), 53.83
13
(C-1), 35.83 (C-4), 25.61 (C-9), 17.86 (C-8), 14.16 (C-5), -5.58 (C-7a), -5.59 (C-7b).
1
H NMR (500.13 MHz, CDCl3): δ (ppm) = 4.20 (t, 3JHH = 9.5 Hz, 2H, H-2), 3.84-3.79 (m,
3H, H-1, H-6a), 3.62 (dd, 2JHH = 9.5 Hz, 3JHH = 7.6 Hz, 1H, H-6b), 2.65 (sxt, 3JHH = 6.9 Hz,
1H, H-1), 1.20 (d, 3JHH = 7.6 Hz, 3H, H-5), 0.89 (s, 9H, H-9), 0.05 (s, 6H, H-7a/b).
EI-MS (70 eV): m/z (%) = 228 (5) [M+•-CH3•]+, 187 (13), 186 (100) [M+•-tBu•]+, 156 (3)
[M+•-2CH3•-tBu•]+,
143
(8),
142
(24),
115
(25)
[Si(CH3)2-tBu]+,
112
(13)
[M+•-•OSi(CH3)2-tBu]+, 84 (7), 75 (8), 73 (14), 59 (8).
CI-MS (CH4): m/z (%) = 284.1 (6) [M+C3H5]+, 272.1 (17) [M+C2H5]+, 244.1 (81) [M+H]+,
228.1 (49) [M+•-CH3•]+, 186.0 (39) [M+•-tBu•]+, 112.0 (16) [M+•-•OSi(CH3)2-tBu]+, 69.0 (29),
57.1 (100) [tBu]+, 55.1 (93).
IR (ATR): ν (cm-1) = 2954/2930/2884/2857 (CH2/CH3), 1666 (C=N), 1472/1463 (CH2/CH3),
1390/1361 (tBu), 1254 (Si-CH3, C-O-C), 1183, 1139, 1091 (C-O-Si), 1057 (C-O-C), 982, 954,
915, 835 (C-O-Si), 775 (Si-CH3).
Elemental analysis (%): C12H25NO2Si, calcd. C 59.21, H 10.35, N 5.75; found C 59.32,
H 10.48, N 5.84.
When applying a similar instruction using imidazole instead of DMAP/Et3N,[2] 3-(tertbutyldimethylsilyloxy)-N-[2-(1H-imidazole-1-yl)ethyl]-2-methylpropanamide was obtained.
Chain transfer during CROP of oxazolines
In analogy to the literature, through cationic ring-opening polymerization of oxazolines (Oxa)
a chain transfer reaction might occur via abstraction of a proton (H+) from the living chain
end which subsequently can initiate the polymerization of a new, unattached POxa chain
(Scheme SI1). Further, resulting enamine moieties can build crosslinks.
The proton-initiated chains were indicated by ESI-MS and 1H NMR.[3-6] To some extent they
can be extracted by ultrafiltration or extraction (SEC: Figure SI1). ESI-MS has proven those
extracted chains as proton-initiated polyoxazolines (ESI-MS: Figure SI2) and 1H NMR
showed evidence of amide-protons within the polymer and consequently proton-initiation
from chain transfer.
proton transfer
N
O X
R
H
N
+
N
O
O
HN
+
R
R
O X
R
new chain
enamine
chain coupling
R
N
O
N
+
O
N
R
O X
R
X
N
enamine
O
R
Scheme SI1: Chain transfer reaction via proton transfer during CROP of oxazolines
Int. [a.u.]
raw polyoxazoline (chain transfer)
extracted chains of lower molar mass
4
5
6
7
8
9
Volume [mL]
Figure SI1: SEC-curve of raw polyoxazoline and extracted low molar mass chains. RI-detection in
DMAc+LiCl.
869.7 [MPn=9(12C)+H]+
870.7 [MPn=9(1• 13C)+H]+
O
H
N
nN
OH
Pn=9
Pn=10
Pn=11
Pn=12
Figure SI2: ESI-MS spectrum (+50 V) of extracted chains of lower molar mass.
Hyperstar-Polymers PVBC-g-POxa
Hyperbranched poly(vinylbenzylchloride): PVBC
Cl
Cl
Cl
Cl
The polymer was synthesized according to the literature.[7, 8]
p-Chloromethylstyrene (61.26 g, 401.40 mmol), bpy (6.27 g, 40.14 mmol) and dry
chlorobenzene (140 mL) were provided and degassed for three times. After addition of CuCl
(1.99 g, 20.10 mmol) in argon flow the mixture was finally degassed until no more bubles
appeared. The solution was stirred for 5 h at 115 °C and finally cooled down to room
temperature.
The reaction mixture was diluted with THF (40 mL) and stirred under air until the colour
changed completely into green. Cu(II) was removed via filtration over alumina with THF.
After concentration to 100 mL under reduced pressure the polymer was precipitated twice
from THF in methanol (2.5 L). After stirring of the suspension for 75 min the polymer was
separated by filtration and dried for 1 d at 50 °C under vacuum to obtain PVBC in 61% yield
(37.35 g) as a colourless solid.
1
H-NMR (500.1 MHz, CDCl3): δ (ppm) = 7.4-6.9 (Ar-H), 6.7 (ArCH=CH2), 5.70/5.21
(ArCH=CH2), 4.8-4.4 (-CHCl-), 4.6 (-CH2Cl), 3.0-1.7 (CH2, CH).
1
H-NMR (500.1 MHz,
C6D6):
δ (ppm) =
7.2-6.8
(Ar-H,
-ArCH=CH2),
5.64/5.09
(-ArCH=CH2), 4.8-4.5 (-CHCl-), 4.18/4.03 (-CH2Cl), 3.1/2.8-1.6 (CH2, CH).
TGA: TDTG,1 = 220 °C, Δm = 23%
TDTG,2 = 446 °C, Δm = 44%.
DSC: amorph, Tg = 67 °C.
DBFréchet = 0.46
DBFrey = 0.49
1
H-NMR (500.1 MHz,C6D6 bzw. CD2Cl2): Mn = 3 400 (±400), Pn = 22 (±3).
SEC (DMAc, MALLS): Mn = 3 000, Mw = 12 000, PD = 4.0.
Cl-Zahl: from 1H-NMR (assumption no elimination):
6.55 mmol Cl/g.
IR (ATR): ν (cm-1) = 3014 (CHar), 2922/2855 (CH2/CH), 1511 (C=Car), 1442/1420 (CH2/CH),
1265, 823 (p-disubst. Aromat), 674 (C-Cl).
Hyperstar-Polymers PE-g-PAlkMA
The solubility of the HSPs prepared was in dependence to the amount of HEMA. Polar HSPs
PE-100%HEMA were soluble in EtOH but insoluble in water, in contrast, unpolar HSPs
without HEMA (PE-PMMA/0%HEMA) were insoluble in EtOH but soluble in THF.
Hyperbranched macroinitiator: PE-MI_3 with a modification degree of 85%
HO
9''
8''
7''
6''
5
2
6
9
7
4
1
O
8
7
3
O
O
4
8
6'
1
5
O
n,hb
7'
9'
8'
10
11
Br
O
O
12
Under an argon atmosphere PE-OH_1 (7.00 g, 23.73 mmol OH) and dry NEt3 (3.17 g,
4.37 mL, 31.32 mmol) were dissolved in dry THF (300 mL) and the solution was cooled
down to 0 °C. A cooled spolution of 2-bromoisobutyrylbromide (7.20 g, 31.32 mmol) in dry
THF (100 mL) was slowly added and the reaction mixture was stirred for 2 h at 0 °C. After
filtration of the solid, precipitation of the polymer from the solution in water (3 L), separation
and drying of the solid for 16 h at 40 °C under vacuum and finally precipitation from THF
(50 mL) in Et2O (1 L), filtration, drying of the precipitate for 16 h at 40 °C under vacuum
including grounding provided PE-MI_3 with 85% ATRP-initiating moieties and 15% free
phenolic OH-groups in 55% yield (6.27 g) as a colourless solid.
1
H NMR (500.13 MHz, CDCl3): δ (ppm) = 7.25 (H-7̕), 7.20 (H-7), 7.08 (H-8̕), 7.06 (H-7̕̕),
6.97 (H-8), 6.72 (H-8̕̕), 2.55 (H-3), 2.35 (H-2), 2.06 (H-12), 1.66 (H-5).
C NMR (125.75 MHz, CDCl3): δ (ppm) = 172.2 (C-1L), 172.0 (C-1D), 170.14 (C-10), 154.1
13
(C-9̕̕), 148.9 (C-9̕), 148.8 (C-9), 146.0 (C-6̕), 145.6 (C-6), 139.7 (C-6̕̕), 128.3 (C-7̕̕, C-7̕),
128.1 (C-7), 121.1 (C-8), 120.6 (C-8̕), 115.0 (C-8̕̕), 55.3 (C-11), 45.38/45.31/45.24 (C-4D),
44.93/44.86 (C-4L), 44.45 (C-4T), 36.2 (C-3), 30.56 (C-12), 30.3 (C-2), 27.8 (C-5).
TGA: TDTG,1 = 290 °C, Δm = 22%
TDTG,2 = 430 °C, Δm = 59%.
DSC: amorphous, Tg = 131 °C.
A molar mass could not be determined via NMR-spectroscopy due to very high
polymerization degrees.
SEC (DMAc, MALLS): Mn = 12 500 g/mol, Mw = 20 500 g/mol, PD = 1.6.
IR (ATR): ν (cm-1) = 3479 (OH), 3041 (CHar), 2974/2935/2877 (CH2/CH3), 1748 (CO), 1503
(C=Car), 1462, 1372, 1265 (C-O), 1207, 1168 (C-O-C), 1131, 1099, 1064 (C-O-C), 1014, 813
(p-disubst. aromatics).
Hyperstar-Polymer: PE-PMMA/0%HEMA
8
9
7
O
6
4
3
2
6'
5
1
O
n,hb
7'
O
O
9'
10
11
12
8'
a
O
c
Br
b
d
O
e
Methylmethacrylate (5.77 g, 6.16 mL, 57.60 mmol) in a mixture of methyl ethyl ketone and
i
PrOH (7:3, 50 mL) was degassed for several times and added to PE-MI_1 (0.80 g,
1.92 mmol Br), bpy (0.60 g, 3.84 mmol) and dry CuCl (0.19 g, 1.92 mmol) under an argon
atmosphere. The suspension was degassed for several times and subsequently stirred for
22.5 h at 50 °C. The reaction mixture was diluted with THF and stirred under air until the
colour changed completely into green. Cu(II) was removed via filtration over alumina with
THF. After removal of the solvent under reduced pressure the polymer was precipitated twice
from THF (50 mL) in water (1 L). After stirring of the suspension for 75 min the polymer was
separated by filtration and dried for 1 d at 40 °C under vacuum to obtain PEPMMA/0%HEMA in 72% yield (4.52 g) as a colourless solid.
1
H NMR (500.13 MHz, DMSO-d6): δ (ppm) = 7.4-7.15 (H-7, H-7̕), 7.15-6.9 (H-8, H-8̕), 3.7-
3.5 (H-e), 2.5-2.2 (H-2/3), 2.2-1.3 (H-a), 1.60 (H-5), 1.25 (H-12), 1.2-0.7 (H-c).
C NMR (125.75 MHz, DMSO-d6): δ (ppm) = 177.3/177.1/176.2/175.5 (C-d), 171.4 (C-1),
13
148.6 (C-9, C-9̕), 145.8 (C-6, C-6̕), 127.9 (C-7, C-7̕), 121.1 (C-8, C-8̕), 55-51 (C-a), 51.7
(C-e), 44.9/44.3/44.0 (C-4, C-b), 29.4 (C-2, C-12), 27.0 (C-5), 20.8/18.5/16.3 (C-c).
Signals of C-3, C-10 and C-11 could not be identified probably due to their low intensity.
TGA: TDTG,1 = 416 °C, Δm = 86%.
DSC: amorphous, Tg = 121 °C.
Pn per arm (1H NMR): Pn(PMMA) = 35 (±7).
SEC (DMAc, MALLS): Mn = 285 000 g/mol, Mw = 980 000 g/mol, PD = 3.4.
IR (ATR): ν (cm-1) = 2992/2949 (CH2/CH3), 1723 (CO), 1484/1434 (CH2/CH3), 1387, 1239
(C-O), 1190, 1142 (C-O-C), 1061, 986, 840 (p-disubst. aromatics), 750 (C-Br).
Additional NMR spectra of the hyperstars
Figure SI3: DEPT135 spectrum of a HSP with P(MMA-b-HEMA)-arms (solvent: DMSO-d6)
Figure SI4: HSQC spectrum of a HSP with P(MMA-b-HEMA)-arms (the traces on the left and on top are
not the projections but the 1H and 13C NMR spectra of this sample thus showing also OH and quarternary
carbon signals not resulting in crosspeaks in the HSQC spectrum). Solvent: DMSO-d6.
Further DLS and AFM results:
PE-OH_1
PE-MI_1
16
14
PE-PMMA/0% HEMA
PE-PMMA/12% HEMA
PE-PMMA/26% HEMA
PE-100% HEMA
Intensity [%]
12
10
8
6
4
2
0
1
10
100
1000
10000
Particle Size [nm]
Figure SI5: Intensity distribution of particle size from DLS of hb core PE-OH_1, hb macroinitiator PEMI_1 and HSPs in DMAc.
PE-100%HEMA
20
PE-100% HEMA
15
[nm]
10
5
0
-5
0
100
200
300
400
500
[nm]
Figure SI6: PE-100%HEMA: AFM-image (left) and height profile (right) of PE-100%HEMA.
1.
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