Supporting Information
One-pot synthesis of amphiphilic diblock copolymers of poly(styrene) and
poly(2-methyl-2-oxazoline) by the direct combination of reverse iodine
transfer polymerization (RITP) and cationic ring-opening polymerization
(CROP) processes
David Rayeroux,1 Vincent Lapinte,2 Patrick Lacroix-Desmazes1*
Institut Charles Gerhardt – UMR 5253 CNRS/UM2/ENSCM - Ingénierie et Architectures
Macromoléculaires (IAM), Ecole Nationale Supérieure de Chimie de Montpellier, 8 rue de
l’Ecole Normale, 34296 Montpellier Cedex 5, France
2
Institut Charles Gerhardt – UMR 5253 CNRS/UM2/ENSCM - Ingénierie et Architectures
Macromoléculaires (IAM), Université Montpellier II, Bat 17, Place Eugène Bataillon, 34095
Montpellier Cedex 5, France.
1
*Correspondence to: Patrick Lacroix-Desmazes (patrick.lacroix-desmazes@enscm.fr)
1
Experimental section
Materials
α,α’-Azobisisobutyronitrile (AIBN, Fluka, 98%) was purified by recrystallization in
methanol. Molecular iodine (I2, Aldrich, 99.8%) was used as received. Styrene (Acros, 99%)
was purified by vacuum distillation before use. 2-Methyl-2-oxazoline (MOx, Aldrich, 98%)
and dimethyl formamide (DMF, sigma Aldrich, 99.8 %) were dried with CaH2, distilled and
stored under a dry nitrogen atmosphere. Spectra/por 6 dialysis membranes (Spectrum
Laboratories, MWCO 1000) were used for dialysis in deionized water.
Instrumentation
The samples were characterized by 1H NMR on a Bruker 400 MHz in CDCl3. Size Exclusion
Chromatography (SEC) with THF as eluent at a flow rate of 1.0 mL.min-1, calibrated with
poly(styrene) standards from Polymer Laboratories, was done on a PL-GPC 50 plus equipped
with a PL-AS RT autosampler from Polymer Laboratories. The SEC apparatus is fitted with
two 300 mm long columns thermostated at 35°C (mixed-C PL-gel 5 m columns from
Polymer Laboratories: 2 × 102 – 2 × 106 g.mol-1 molecular weight range) and comprises an
integrated chromatography system: a micro-volume double piston pump, and a deflection type
refractometer detector. SEC with 0.1M LiBr/DMF as eluent, calibrated with poly(methyl
methacrylate) standards from Polymer Laboratories, was run with a Varian Prostar (model
210) pump at a flow rate of 0.8 mL.min-1 using two 300 mm long, mixed-D PL-gel 5 m
columns (molecular weight range: 2 × 102 – 4 × 105 g.mol-1 from Polymer Laboratories)
thermostated at 70°C, connected to a Shodex (model RI-101) refractometer detector.
2
Synthesis of poly(styrene) homopolymer by bulk RITP of styrene: PS-I
In one typical experiment, 0.9081 g (3.58 mmol) of iodine, 1.1821 g (7.20 mmol) of AIBN,
and 20.0446 g (0.1925 mol) of styrene were placed in a 50 mL round bottom schlenk flask
fitted with a magnetic stirrer. The latter was fitted with a septum and after three freeze-thawpump cycles, it was heated in an oil bath at 80°C in the absence of light under argon
atmosphere for 2 hours and 15 minutes. The schlenk containing the crude product was then
dipped into liquid nitrogen to stop any further reaction. The monomer conversion and
molecular weight of the crude product were obtained by 1H NMR in CDCl3 and SEC in THF
respectively.
Synthesis of diblock copolymers poly(styrene)-block-poly(2-methyl-2-oxazoline) (PS-bP(MOx)) by CROP of MOx in solution
To a 50 mL round bottom schlenk equipped with a magnetic stirrer were added 4.0116 g of
the crude mixture of poly(styrene) homopolymer (60% styrene conversion) (i.e. 2.4070 g of
PS-I, 1.08 mmol of PS-I according to Mn,NMR), 3.5649g (0.0420 mol) of MOx and 10 mL
(9.445 g, 0.1292 mol) of DMF. The flask was heated at 80°C for 18 hours under argon
atmosphere in the absence of light. A yellowish oily liquid was obtained after the elapsed time
of 18 hours. This crude product was purified three times by dissolution in chloroform and
precipitation in diethyl ether to get rid of any unreacted reactants and/or side products. 1H
NMR in CDCl3 and SEC in DMF were performed at each step of the purification steps on the
soluble (FXS) and insoluble (FXI) fractions. Dialysis of the final product (F3I) was then
conducted and the resulting products (F3ID retentate and F3ID permeate) were analyzed by 1H
NMR in CDCl3 and SEC in DMF.
3
Supporting figures and table
Figure S1. Simplified mechanism of RITP of styrene.
Figure S2. Polymers based on MOx using molecular iodide initiators.
4
Figure S3.Amphiphilic diblock copolymers based on MOx using iodide macroinitiators.
a
a
b
b
c
b
d
c
d
c
b
a a
d
Figure S4. 1H NMR spectrum of crude PS-I prepared by RITP (in CDCl3, 400 MHz).
5
a
a
b
b
f
f
e
c
f
e
c
b
a a
Figure S5. 1H NMR spectrum of crude product PS-b-P(MOx) (in CDCl3, 400 MHz).
a
a
b
b
c
f
f
e
e
f
c
b
a a
Figure S6. 1H NMR spectrum of insoluble fraction F3I (in CDCl3, 400 MHz).
6
f’
f’
e’
e’
f’
Figure S7. 1H NMR spectrum of dialyzed product F3ID (permeate) (in CDCl3, 400 MHz).
Table S1. Mass balance determined by 1H NMR at each step of the purification of the diblock
copolymer PS-b-P(MOx).
Crude
product
(g)
F1S(g)
F1I (g)
F2S (g)
F2I (g)
F3S (g)
F3I (g)
PS
2.91
1.30
1.09
0.24
0.98
0.30
0.49
2.33
80
P(MOx)
3.80
0.03
3.35
0.01
3.51
0.02
3.60
3.64
96
Total(1)
Yield(2)(%)
(g)
I: insoluble; S: soluble
(1) Total = F1S + F2S +F3S + F3I
𝑇𝑜𝑡𝑎𝑙
(2) Yield= 𝐶𝑟𝑢𝑑𝑒𝑝𝑟𝑜𝑑𝑢𝑐𝑡 × 100
7