We report QENS measurements from PS-b-PFOA aggregates in supercritical CO2. These consist of dense cores of CO2-insoluble polystyrene surrounded by a `corona' of PFOA surfactant molecules whose CO2-philic groups interface with supercritical CO2. Lineshapes are dominated by localised diffusive modes and segmental dynamics of the anchored finite-length PFOA chains. For Q degrees similar to 0.6 Angstrom(-1), we obtain effective diffusion coefficients of approximate to 0.8x10(-6) cm(2)/sec. At higher Q, a single component is not sufficient as shown by excess intensity on the flanks. For Q>1.5 Angstrom(-1), the wings reflect contributions due to a distribution of faster, more localised chain modes.
|Name||AIP Conference Proceedings|
|Publisher||American Institute of Physics|
|Conference||Nuclear and Condensed Matter Physics: VI Regional Conference|
|Period||14/10/99 → 15/10/99|