Journal Article

PreJuSER-19618

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structure and dynamics of balanced supercritical CO2-microemulsions

Klostermann, M. ; Strey, R. ; Sottmann, T. ; Schweins, R. ; Lindner, P. ; Holderer, O.FZJ* ; Monkenbusch, M.FZJ* ; Richter, D.FZJ*

2012
Royal Society of Chemistry (RSC) Cambridge

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Please use a persistent id in citations: http://hdl.handle.net/2128/7395  doi:10.1039/C1SM06533E

Abstract: Balanced scCO(2)-microemulsions contain equal volumes of water and CO2 and are a novel class of microemulsions of substantial interest for both fundamental research and technical applications. One existing feature of these systems is that the solvent quality of scCO(2), and hence the overall microemulsion properties, is tuned simply by adjusting pressure, which is not possible with "classical" microemulsions containing oil instead of CO2. Motivated by this, we systematically investigated the phase behavior, the microstructure, and the dynamics of balanced microemulsion systems of the type H2O-CO2-Zonyl FSO 100/Zonyl FSN 100. In systematic phase behavior studies, we found that upon increasing pressure, CO2 and water are more efficiently solubilized. Small angle neutron scattering (SANS) experiments were conducted in order to determine the topology and the length scales of the underlying microstructure. The results obtained strongly suggest the existence of bicontinuously structured microemulsions with an adjustable characteristic length scale of up to 330 angstrom. From a quantitative analysis of the SANS data, we found that at a fixed microemulsion composition the stiffness of the surfactant membrane is increased solely by increasing the pressure, whereby the renormalization corrected (i.e. bare) bending rigidity kappa(0), SANS rises from kappa(0,SANS) 0.88 k(B)T at 200 bar to 0.93 k(B)T at 300 bar. These findings were confirmed with high pressure neutron spin echo experiments.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Key Technologies (1st) ; Soft Condensed Matter (2nd) ; J

Note: We wish to thank L. Kramer for his help in the early stages of these studies, O. Klems and V. Dahl for their assistance with the SANS experiments and Klaus Wormuth for his careful revision of the manuscript. Furthermore we would like to thank H. Metzner and the technical workshop as well as W. Rohl for their essential contributions in the development of the high-pressure cells. We also thank the Fund of the Chemical Industry in Germany (VCI), the International Helmholtz Research School of Biophysics and Soft Matter (IHRS BioSoft) as well as the EU-network of excellence SoftComp for financial support. In addition we wish to thank DuPont for the free Zonyl samples. Finally we thank the ILL and the JCNS for the opportunity to perform neutron scattering experiments and for financial support.

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Contributing Institute(s):

1. Neutronenstreuung (ICS-1)
2. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
3. Neutronenstreuung (JCNS-1)

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. J-NSE: Neutron spin-echo spectrometer (NL2ao)

Appears in the scientific report 2012

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Database coverage:
; ; Allianz-Lizenz / DFG ; Current Contents - Social and Behavioral Sciences ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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