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Caroline BARRERE

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hydrophilic Poly(Ethylene Oxyde) hydrophobic Poly(Styrene) m X Y A wide range of applications (advanced nanomaterials, biocompatible drug delivery systems). Properties depend on : - nature and size of block - end groups nature - molecular weight distribution (M n, M w ). 16 October 2009Journée RMN du grand Sud Est2

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16 October 2009Journée RMN du grand Sud Est3 AdvantagesDisadvantages Mass Spectrometry MALDI-TOF Direct method. M n and M w estimation. Does not work with amphiphilic copolymers. Steric Exclusion Chromatography M n and M w estimation. Indirect method. Calibrated with homopolymers. Response depends on the detection mode. Weak adsorption. PGSE NMR Homopolymers M w determination. Calibration curve valid on any instrument. Indirect method. To extend this method to PEO-b-PS copolymers. Quantitative 1 H NMR Direct method. M n determination. End group signal identification. Only M n determination.

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Stokes-Einstein equation for spherical particles in dilute solution : 16 October 2009Journée RMN du grand Sud Est4 D : Self diffusion coefficient k B : Boltzmann constant T : Temperature η : Solvent viscosity r H : Molecular hydrodynamic radius

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16 October 2009Journée RMN du grand Sud Est5 à gradients de champ pulsés Hahn Pulse sequence RF g 90° 180° δ γgγg δ γgγg t τ τ B0B0B0B0 Δ CodingDecoding Total phase shift=γgδ(z 1 -z 2 ) (z 1 - z 2 ) = 0 maximum echo (z 1 - z 2 ) 0 attenuated echo D measurement Intensityg D (±3%)

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D PS =2.869x10 -8 M w -0.5539 D PEO =2.890x10 -8 M w -0.5885 Florys law : Calibration curves obtained for PEO and PS in dilute solution ( 3 mg mL - 1 in CDCl 3 at 300 K ). 16 October 2009Journée RMN du grand Sud Est6 M w determination at ± 10% Mazarin, M.; Viel, S. ; Allard-Breton, B. ;Thévand, A. ; Charles, L. Anal. Chem. 2006, 78, 2758-2764 Mazarin, M.; Viel, S. ; Allard-Breton, B. ;Thévand, A. ; Charles, L. Anal. Chem. 2006, 78, 2758-2764.

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PEO-b-PS block copolymers synthesized from PEO 2000 and 5000 g.mol -1. Impossible caracterization of amphiphilic copolymers by MALDI-ToF/MS Strategy : Hydrolysis in basic conditions. 16 October 2009Journée RMN du grand Sud Est7 XY Homopolymers analysis by MALDI-ToF/MS. Girod, M.; Mazarin, M. ; Phan, T. N. T. ; Gigmes, D. ; Charles, L. J. Polym. Sci., Part A : Polym. Chem. 2009, 47, 3380-3390 Girod, M.; Mazarin, M. ; Phan, T. N. T. ; Gigmes, D. ; Charles, L. J. Polym. Sci., Part A : Polym. Chem. 2009, 47, 3380-3390.

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16 October 2009Journée RMN du grand Sud Est8 1 st Strategy : Using homopolymers calibration curves. PGSE PEO calibration curve PS calibration curve # D ( x 10 - 10 m 2 s -1 ) M w T (g mol -1 ) Dev. (%) M w T (g mol -1 ) Dev. (%) A11.4747874+213581+76 A21.13512276-3121770+23 A31.07713421-3023932+24 A40.97615865-3428588+19 B11.3848764-715217+61 B21.25610335+418131+83 B31.10212907-1222961+56 B40.94816669-1730131+49 B50.87519101-3234821+23 Deviation greater than 10% (Generaly admitted value for M w determination by PGSE). PEO calibration curve PS calibration curve

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An hydrodynamic model should be used in order to interpret diffusion data. Because copolymers are strongly amphiphilic, we assume a segregated conformation where the two blocks have no interactions. 16 October 2009Journée RMN du grand Sud Est9

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2 nd Strategy : spherical model 16 October 2009Journée RMN du grand Sud Est10 We obtained D calc = 0.88 D exp The spherical model is not suitable. Stokes-Einstein Flory

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General Stokes-Einstein equation: Perrins works on ellipsoidal molecules diffusion : With for a revolution ellipsoid. 16 October 2009Journée RMN du grand Sud Est11 r revolution r equatorial r revolution r equatorial Perrin, F., J. Phys. Radium, 1936, 1, 1-11

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# M w T (g mol -1 ) Dev. (%) A112658+64 A224489+38 A328261+47 A435190+47 B112159+29 B214799+49 B320327+38 B428297+40 B535880+27 Prolate ellipsoïdal model : 16 October 2009Journée RMN du grand Sud Est12 Expression of ρ : Self diffusion coefficient of a sphere with the same volume (D 0 ) : Expression of D prolate : Deviation greater than 10%.

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# M w T (g mol -1 ) Dev. (%) A19041+17 A215762-11 A317780-8 A421681-10 B18481-10 B210599+7 B314860+1 B419840-2 B523910-15 Oblate ellipsoidal model : 16 October 2009Journée RMN du grand Sud Est13 Expression of ρ : Self diffusion coefficient of a sphere with the same volume (D 0 ) : Expression of D oblate : The deviation is overall smaller than the 10 % tipically obtained for homopolymers. The Oblate ellipsoidal model is valid to study these PEO-b-PS block copolymers.

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Copolymers adopt a segregated conformation with no interactions between the two blocks. Oblate ellipsoid modeled well the PEO-b-PS blocks copolymers conformation in dilute solution. 16 October 2009Journée RMN du grand Sud Est14 Barrère, C. ; Mazarin, M. ; Giordanengo, R. ; Phan, T. N. T. ; Thévand, A. ; Viel, S. ; Charles, L. Anal. Chem, 2009, 81, 8054 - 8060. AdvantagesDisadvantages RMN PGSE M w determination. Fast. Calibration curve valid on any instrument. Indirect method. Only M w.

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16 October 2009Journée RMN du grand Sud Est15 Organizing committee SACS team, LCP : Pr. Laurence Charles CES team, ISM2 : Dr. Stéphane Viel CROPS team, LCP Dr. Trang NT. Phan Spectropole : Privileged Access to the Instrumental Park (FEDER OBJ 2142-3341 ) ARKEMA ® (alcoxyamine)

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