title: Hierarchical supramolecular structuring and dynamical properties of water soluble polyethylene glycol-perylene self-assemblies.
abstract: The structural and dynamical properties of dilute aqueous solutions of poly(ethylene glycol)-perylene diimides (PEG(n)-PDI) have been investigated by means of static and dynamic light scattering, TEM microscopy, and small-angle X-ray scattering experiments. The amphiphilic PEG(n)-PDI molecules first self-assemble into stable and compact primary stacks of a few units of planar PDI through hydrophobic and π-π interactions. These primary stacks subsequently arrange in large and globular aggregates of typically 100-250 nm via weak PEG chain interpenetration. Surprisingly, the scattered electric field autocorrelation function g((1))(q,t) measured by dynamic light scattering evolves over very long periods of times (several months) and up to a bimodal distribution. The fast relaxation mechanism is associated to the diffusion of free primary stacks, whereas the slower relaxation still indicates the presence of large self-assemblies. Kinetic experiments show that the large supramolecular aggregates slowly release the free primary stacks whose proportion increases with time. This dissociation depends on several parameters such as PEG side chain length, total concentration, and shaking.
authors.affiliation: Laboratoire Matière et Systèmes Complexes (MSC), UMR CNRS 7057, Université Paris Diderot-Paris 7, bâtiment Condorcet, 75205 Paris cedex 13, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jouault
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Xiang
authors.forename: Emilie
authors.initials: E
authors.lastname: Moulin
authors.forename: Gad
authors.initials: G
authors.lastname: Fuks
authors.forename: Nicolas
authors.initials: N
authors.lastname: Giuseppone
authors.forename: Eric
authors.initials: E
authors.lastname: Buhler
mesh_terms: D007094:Imides / Q000737:chemistry*; D007700:Kinetics; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D010316:Particle Size; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D007094:Imides; D046911:Macromolecular Substances; C521332:perylenediimide; D014867:Water; D011092:Polyethylene Glycols; D010569:Perylene