Cooperative, bottom-up generation of rigid-rod nanostructures through dynamic polymer chemistry.
Fiche publication
Date publication
novembre 2010
Auteurs
Membres identifiés du Cancéropôle Est :
Pr LEHN Jean-Marie, Dr SCHMUTZ Marc
Tous les auteurs :
Folmer-Andersen JF, Buhler E, Candau SJ, Joulie S, Schmutz M, Lehn JM
Lien Pubmed
Résumé
A set of carbazole-and benzene derived di(aldehyde) and di(acylhydrazine) monomers containing hexaglyme groups to impart water solubility has been synthesized Mixing a given di(aldehyde) and di(acylhydrazine) pair in acidic aqueous solution causes polymerization through reversible acylhydrazone condensation The structures of the resultant amphiphilic polyacylhydrazones have been studied using H-1 NMR spectroscopy, matrix assisted laser desorption ionization mass spectrometry, small angle neutron scattering, transmission electron microscopy, size exclusion chromatography/multi-angle laser light scattering (SEC-MALLS) and UV-visible and fluorescence spectrophotometries All the available data support the existence of structurally related rod like nanostructures of variable lengths and constant diameters of approximately 5 nm in all cases, which are interpreted as corresponding to individually folded polymer chains On the basis of these studies, molecular models are proposed in which the hydrophobic, aromatic polymer backbones assume helical conformations allowing for hydrophobically driven pi stacking, while exposing the hydrophilic hexaglyme groups to the solvent The molecular models are in agreement with the observed physical dimensions of the nanostructures, and are further supported by the observation of strong hypochromic effects on changing the solvent from dimethylformamide to water Additionally, the reversible polymerization process is found to be cooperative H-1 NMR and SEC MALLS studies reveal severe deviations from statistically predicted product distributions under imbalanced stoichiometry, which are characteristic of nucleation-elongation behaviour (C) 2010 Society of Chemical Industry
Référence
Polym Int. 2010 Nov;59(11):1477-91.