Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux (IPREM) Équipe Physico-Chimie des Polymères UMR CNRS 5254/ Université de Pau et des Pays de l’ Adour

Controlled (co)polymer architectures by Nitroxide Mediated Polymerization (NMP) Theory and modelling of architecturally complex and self-organizing macromolecular systems Composite polymer gels filled with conducting polymers Chemical modification and properties of polysaccharides … Expertise:

Controlled (co)polymer architectures by Nitroxide Mediated Polymerization (NMP) Laurent Billon

pH responsive micelles of double-pH sensitive amphiphilic gradient copolymers

Self-Assembly PS Macro-initiator Direct Nitroxide Mediated Polymerization of Acrylic Acid PS – b - PAA Amphiphilic Dibloc Copolymer Synthetic approach: direct NMP of styrene & acrylic acid  ”Classical “ synthetic route and behavior in aqueous media  New synthetic route and behavior in aqueous media " Living " PAA Addition of Styrene Self-Assembly ?? PAA – b – (PAA – co – PS) Amphiphilic dibloc copolymer ?? soluble in water at 25°C

Small Angle Neutron Scattering: pH-responsive behavior PAA 76 - b -(PS 35 – grad - PAA 73 )  Aggregates with a repulsive corona  correlation peak  Shift of correlation peak of structure to high q values when pH increases  Decrease in distance between micelles decrease in aggregation #  pH-responsive, « dynamic » micelles!

PS 14 - b - PAA 135 (PS 14 – grad – PAA 33 ) -b- PAA 106 « frozen » micelles «dynamic» micelles Response to variation in pH: influence of the copolymer architecture

Effect of introduction of pH sensitive ionic monomers in the core block: increasing CMC (penalty for de-ionization of ionic monomers in the core) decreasing aggregation number (decrease of interfacial tension due to ionization of pH sensitive monomers at the core surface) « softening » of the core

Responsive polyelectrolyte brushes at aqueous interfaces

Synthetic route for PAA brushes: NMP initiated from the surface initiator anchoring group cleavable group Self-Assembled Monolayer (SAM) OH In-situ CRP SG1 Advantages: - good controll of Mw, low polidispersity - no postmodification (hydrolysis) - re-initiation, co-polymerization possible

AFM single molecule force spectroscopy: desorption force measurements Collaboration: LPCP Pau/LMU Munich

AFM single molecule force spectroscopy: insight in molecular weight distribution and chain conformations… Correspondence between GPC (polymerization in solution + postmodification) with AFM plateau distribution at pH 6 Plateau length distribution changes between pH 6 and pH 11, shift of the maximum from 600 nm to 400 nm Appearance of bimodal plateau length distribution below pH 5: cooperative effects ???

Double pH sensitive polyelectrolyte brushes: reversible nano-patterning of the interface AFM in liquid cell : wafer/ PAA 130 -(PAA 80 -co-PS 55 ) LPCP Pau/CRPP Pessac pH Collaboration: Double pH sensitive copolymer

Theory and modelling of architecturally complex and self-organizing macromolecular systems Oleg Borisov

Nano-scale aggregates of diblock copolymers Spherical micelles Cylindrical worm-like micelles Vesicles hydrophilic (ionic) hydrophobic

Experiment: A.Eisenberg Self-assembly of block polyelectrolytes in aqueous solution: morphological transitions Area per chain, s Morphology, i Driving force and physical mechanism of morphological transitions: NANA NBNB ionic salt i=3 i=2 i=1

C salt pH=pK Re-entrant morphological transitions in aggregates of pH-sensitive block polyelectrolytes No experiment yet! NANA NBNB pH-sensitive salt Theoretical phase diagram Ionization-aggregation coupling in pH-sensitive polymers leads to novel self-assembly features

Analytical theory prediction confirmed by SCF numerical modelling Sphere-to-sphere first order phase transition in pH-sensitive polyelectrolyte micelles No experiment yet! Weakly ionized corona Adding salt/increasing pH Aggregation # Strongly ionized corona pH

multiple driving forces … Self-assembled Janus micelles Micellar InterPolyelectrolyte Complexes Interaction of proteins with polyelectrolyte brushes AB A B   B A M.Cohen Stuart et al M.Ballauff et al A.Müller et al

Core-shellsAmphiphilic molecular brushes Miktoarm stars A A A A C B B B B topological complexity of amphiphilic macromolecules …

Combining chemical and topological complexity in a single macromolecule …

Stéphanie Reynaud, Bruno Grassl Composite polymer gels filled with conducting polymers

Hydrogel à base d’un réticulant difonctionnel : AcrylamideN,N'-méthylène-bis acrylamide HYDROGEL COMPOSITE Système conducteur : Nano particules polyaniline PS Coupe transversale Hydrogels composites chargés de PANI formation du polymère conducteur

Variation des conditions expérimentales ? gonflement pendant 8h d’un échantillon PAM + latex PS banc optique CAMERACDD Acquisition et traitement des images cellule : échantillon d’hydrogel Éclairage par DEL Hydrogels composites chargés de PANI Étude Cinétique du gonflement ?

Hydrogels composites chargés de PANI Applications : relargage électrocontrôlé 5 V, 3 min Application d’un tension  modification de l’état d’oxydation du polymère conducteur (PANI)  relargage d’ions Cl - dans le milieu + - Tension (V)  (s/cm) Hydrogel composite PAM - nanoparticules PS/PANI Gel PAM Gel PAM + PS/PANI

Chemical modification and properties of polysaccharides Jacques Desbrieres

In collaboration with: Institute of Macromolecular Compounds, St.Petersburg, Russia Wageningen University, the Netherlands CEA-Saclay, France LSST, ETH Zurich, Switzerland Charles University of Prague, Czech Republic