Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Poster: Nanoparticles and Composite Materials
CPP 8.14: Poster
Montag, 26. März 2012, 17:30–20:00, Poster A
Investigation of wetting-dewetting transition of polymer grafted nanoparticles in polymer matrix — •Chang Jong Kim1, Tinka Spehr1, Bernd Stühn1, Markus Mazurowski2, Katrin Sondergeld2, Roland Klein2, and Matthias Rehahn2 — 1TU Darmstadt, Experimentelle Physik kondensierter Materie — 2TU Darmstadt, Ernst-Berl-Institut für Technische und Makromolekulare Chemie
The dispersion of nanoparticles in a polymer matrix is generally improved by grafting polymers from the surface of the nanoparticles, when the grafted polymers are miscible with the surrounding matrix. For a given grafting density and molecular weight of grafted polymer the particle dispersion and wetting properties are known to sensitively depend on the ratio of the length of the surrounding polymer matrix to that of the grafted polymer chain. As the length of the matrix polymer chain exceeds that of the grafted polymer, chains of the polymer matrix are dewetted and particles aggregate. In our experiments polystyrene (PS, Mn∼30kDa) was grafted from spherical silica (SI) as well as deuterated polystyrene (d-PS) particles. These particles (wt∼1%) were dispersed in d-PS matrices with various molecular weights and measured by small angle x-ray scattering (SAXS) and small angle neutron scattering (SANS). The particle dispersion and the change of the conformation (wetting-dewetting transition) of grafted PS chains are probed by analyzing SAXS and SANS scattering curves. First indication for dewetting mechanism were found for PS@d-PS particles when the molecular weight of PS matrix exceeded that of grafted PS.