Berlin 2008 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: POSTERS Colloids, Nanoparticles and Aggregates

CPP 21.18: Poster

Wednesday, February 27, 2008, 16:00–18:30, Poster A

Evaluation of USAXS data obtained from colloidal crystals in latex films — •Rainer Gehrke — HASYLAB at DESY, Notkestrasse 85, D-22607 Hamburg, Germany

Compressed films of spherical core-shell particles with a rigid thermoplastic core (polystyrene) and a soft elastomeric shell (polymethyl methacrylate-polyethylacrylate) show a regular arrangement of the spheres. Close to the film surface the particles are ordered in an fcc lattice with the (111) net-planes parallel to the surface while in the bulk crystal-like domains with no preferred orientation are formed. USAXS measurement were performed by varying the angle between the incident beam and the surface normal stepwise from 0 degree (perpendicular incidence) to almost 90 degrees (grazing incidence) using 0.15 nm wavelength and a two-dimensional detector. Data evaluation allows separation of the scattering contributions from bulk and crystal-like top and bottom layers. The fraction of crystal-like ordered material can be estimated as well as the quality of its spatial and orientational ordering.