Journal Article

PreJuSER-9819

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Self-Assembled Nanoparticles from a Block Polyelectrolyte in Aqueous Media: Structural Characterization by SANS

Papagiannopoulos, A. ; Karayianni, M. ; Mountrichas, G. ; Pispas, S. ; Radulescu, A.FZJ*

2010
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/jp1009912

Abstract: We present a small angle neutron scattering (SANS) study of polystyrene-b-sodium (sulfamate/carboxylate) isoprene (PS-PSCI) nanoparticles in aqueous media. The SANS experiments are complemented by static and dynamic light scattering measurements. A detailed analysis of the scattering form factor obtained by SANS for the self-assembled block polyelectrolyte spherical nanoparticles implies a two-region power-law model for the radial volume fraction profiles. The theoretically predicted scaling of the osmotic brush regime phi(r) approximately r(-2) for the inner region and the osmotic annealing brush regime phi(r) approximately r(-8/3) for the outer region are in agreement with our experimental findings. A concentrated shell of PSCI polyelectrolyte chains collapsed on the polystyrene core is needed in the form factor analysis so that the aggregation number of the nanoparticles is self-consistent. The self-assembled nanoparticles are found to be kinetically frozen i.e. their aggregation number is not sensitive to the solution conditions and is defined by the preparation protocol. The size of the spherical nanoparticles tends to decrease upon the addition of salt and the drop of pH.

Keyword(s): Butadienes: chemistry (MeSH) ; Carboxylic Acids: chemistry (MeSH) ; Hemiterpenes: chemistry (MeSH) ; Molecular Structure (MeSH) ; Nanoparticles: chemistry (MeSH) ; Neutron Diffraction (MeSH) ; Pentanes: chemistry (MeSH) ; Polystyrenes: chemistry (MeSH) ; Scattering, Small Angle (MeSH) ; Water: chemistry (MeSH) ; Butadienes ; Carboxylic Acids ; Hemiterpenes ; Pentanes ; Polystyrenes ; polystyrene sulfonic acid ; Water ; isoprene ; J

Note: The SANS experiments have been supported by the European Commission under the seventh Framework Programme through the Key Action: Strengthening the European Research Area, Research Infrastructures. Contract No.: 226507 (NMI3). The SANS work is based on experiments performed at the Mich Centre for Neutron Science JCNS, Forschungszentrum Julich, Germany.

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Contributing Institute(s):

1. Streumethoden (IFF-4)
2. Neutronenstreuung (IFF-5)
3. JCNS (Jülich Centre for Neutron Science JCNS (JCNS) ; JCNS)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Experiment(s):

1. KWS-2: Small angle scattering diffractometer (NL3ao)

Appears in the scientific report 2010

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