Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 58: Polymer Dynamics II

CPP 58.3: Vortrag

Freitag, 4. April 2014, 10:15–10:30, ZEU 114

Local Dielectric Spectroscopy to detect Dynamic Heterogeneity and Phase Separation Kinetics in Miscible Poly(vinyl acetate)/Poly(ethylene oxide) Blends — Tomas P. Corrales¹, David Laroze², George Zardalidis³, George Floudas³, Hans-Jürgen Butt¹ und •Michael Kappl¹ — ¹MPI for Polymer Research, Mainz, Germany — ²Instituto de Alta Investigación, Universidad de Tarapacá, Arica, Chile — ³Department of Physics, University of Ioannina, Ioannina, Greece

We employed atomic force microscopy based local dielectric spectroscopy (LDS) to analyze the miscible blend composed of poly(vinyl acetate) (PVAc) and poly(ethylene oxide) (PEO). The two homopolymers have very different relaxation times and glass temperatures, which give rise to dynamic heterogeneity in their blends. The aim was to study the dynamic heterogeneity in films as a function of the film thickness. Measurements of the local blend composition at the nanoscale show that LDS is indeed sensitive to the dynamic heterogeneity. In thin films, phase segregation of the homopolymers occurs due to heterogeneous nucleation and crystallization of PEO. We were able to follow the kinetics of phase demixing by detecting the change in local composition of blends including depletion zones of PEO in the PVAc/PEO blend around the PEO crystals via LDS spectra. These results open new possibilities for studying surface segregation in polymer blends, local variation in polymer concentration, and interdiffusion at polymer-polymer interfaces as a function of annealing temperature with LDS.