synthesis of “smart” block copolymers: efficiency of ... · synthesis of “smart” block...
TRANSCRIPT
M. Vachaudeza, R. Minchevaa, C.-‐A. Fus6nb, L. Mespouillea, O. Coulembiera, J.-‐F. Gohyb, Ph. Duboisa
a Laboratory of Polymeric and Composite Materials (SMPC), University of Mons-‐Hainaut, 20 Place du Parc, 7000 Mons, Belgium b InsEtute of Condensed MaFer and Nanosciences (IMCN), Catholic University of Louvain, Place Louis Pasteur, 1, 1348, Louvain-‐la-‐Neuve, Belgium
SYNTHESIS OF “SMART” BLOCK COPOLYMERS: EFFICIENCY OF AQUEOUS ATRP STRATEGY
Aim: Synthesis of « smart » triblock acrylamide-‐based copolymers by aqueous ATRP in « one-‐pot » process
Poly(ethylene oxide) PEO
Biocompatible
Thermoresponsive
N-isopropylacrylamide NIPAAm
pH-responsive PEO-b-PNIPAAm
Strong polyacid
N,N-dimethylaminoethyl acrylate DMAEMA
2-acrylamido-2-methyl-1-propane sodium sulfonate AMPSNa
PEO-b-PNIPAAm-b-PDMAEA
PEO-b-PNIPAAm-b-PAMPSNa
PEO (g/mol)
Conv. (%)
Mn th (g/mol)
Mn NMR (g/mol)
PDI
650 93 5,260 6,410 1.19
4,800 99 5,670 5,550 1.15
PEO-b-PNIPAAm
13 14 15 16 17 18 19
❍ PEO ◊ PNIPAAm
PEO 650 g/mol
PEO-b-PNIPAAm-b-PDMAEA
Elution volume (ml)
13 14 15 16 17 18 19 20
Elution volume (ml)
PEO 650 g/mol -‐ 240
∆ PDMAEA
14 15 16 17 18 19 20 21 22 Elution volume (ml)
PEO 650 g/mol
∆ PAMPSNa
PEO-b-PNIPAAm-b-PAMPSNa
PEO (g/mol)
Time (min)
Conv. (%)
Mn th (g/mol)
Mn NMR (g/mol)
PDI
650 3.20 26 1,865 2,580 1.25
650 240 69 4,140 5,150 1.25
4,800 1,110 65 10,330 6,610 1.49
PEO (g/mol)
Time (min)
Conv. (%)
Mn th (g/mol)
Mn NMR (g/mol)
PDI
650 21 26 1,865 2,580 1.19
4,800 1,200 99 24,970 25,380 1.24
THERMORESPONSIVITY
Cloud point 49°C
PEO12-‐b-‐PNIPAAm-‐b-‐PDMAEA
• Absence of cloud point for others defined triblock copolymers explained by an increase in the hydrophilic character when:- presence PAMPSNa (strong polyacid) - presence of longer PEO
1g/L – pH 7
pH-RESPONSIVITY
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pH 2.5 pH 9
NMR AFM pH 7 120 nm
0.0 1: Height 1.4 μm
Linear dependence
SPHERICAL shape
Rh ∼ 210 nm PI ∼ 0,1
DLS pH 2.5
q2 (cm -‐2)
Γ (s
-‐1)
25°C 30°C 45°C 55°C
Rh∼60 -‐ 90 nm
55°C 55°C
Acknowledgments
This work has been supported by the European Commission and Région Wallonne FEDER program (Materia Nova) and OPTI”MAT program of excellence, by the Interuniversity Attraction Pole program of the Belgian Federal Science Policy Office (PAI 6/27) and by FNRS-FRFC. MV, CAF and OC thank the « Fonds National de Recherche Scientifique ».
Triblock copolymers defined as switchable amphiphilic copolymers able do present such character depending on external conditions like pH and temperature.
H2O/DMF (1/1), 20°C
CuCl.Me6TREN
[NIPAAm] = 2M
35 min (PEO 650)
90 min (PEO 4,800)
H2O/DMF (1/1), 20°C CuCl.CuCl2.Me6TREN (1-‐1-‐5)
[DMAEA] = 1.5 M
H2O/DMF (1/1), 20°C CuCl.CuCl2.Me6TREN (1-‐1-‐2) [AMPSNa] = 0.8 M
Conclusions ● Controlled synthesis of poly(acrylamide) based-di- and triblock copolymers by aqueous ATRP in a « one-pot » process.
● Defined and spherical micelles at 55°C.
Intensity
of e
ach block signals
LCST ∼ 32°C pKa 7.4