Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: Nanoparticles and Composite Materials II (joint session CPP, BP)

CPP 9.5: Talk

Monday, March 16, 2015, 16:00–16:15, C 243

Organic inorganic hybrid PU-POSS networks: A multi-length-scale investigation of morphology and a multi-time-scale investigation of dynamics — •Konstantinos N. Raftopoulos^1,2, Stefanos Koutsoumpis³, Malgorzata Jancia², Konstantinos Kyriakos¹, Edyta Hebda², Christine M. Papadakis¹, Krzysztof Pielichowski², and Polycarpos Pissis³ — ¹TU München, Physik-Department, Fachgebiet Physik weicher Materie, Garching — ²Cracow University of Technology, Department of Chemistry and Technology of Polymers, Poland — ³National Technical University of Athens, Department of Physics, Greece

Polyhedral oligomeric silsesquioxanes (POSS) bridge the gap between nanoparticles and conventional chemical reagents. A wide variety of organic, ligands bind on a sub-nm siliceous core, and allow it to participate as a nanobuilding block on the very structure of the macromolecular chain. Here, octa-OH functional moieties crosslink a phase separated polyurethane. On the basis of X-ray diffraction in a wide q-range covering both WAXS and SAXS and atomic force microscopy we show that POSS reside in the soft phase, and the hard microdomains become progressively thinner with increasing POSS content. The segmental dynamics of the soft phase slow down as a result of both crosslinking and diminishing microphase separation, as evidenced by differential scanning calorimetry and broadband dielectric spectroscopy. Interestingly, all the effects show a step-like behavior between 4 and 6 wt% of POSS, possibly as a result of a percolation of the POSS crosslinked phase.