TY - CONF A1 - Schönhals, Andreas A1 - Madkour, Sherif A1 - Szymoniak, Paulina T1 - Complex dynamics of ultra-thin films of blends of polystyrene/ poly(vinyl methyl ether) by nanosized relaxation spectroscopy N2 - In the course of miniaturizing modern technology down to the molecular scale, understanding the materials behavior has to be investigated and deviations from the bulk have to be understood. A combination of nano-sized relaxation spectroscopies (Broadband Dielectric Spectroscopy (BDS) and Specific Heat Spectroscopy (SHS)) employing AC nanochip calorimetry were utilized to investigate the glassy dynamics of ultra-thin films of blends of Poly (vinyl methyl ether) (PVME) / Polystyrene (PS) (50:50 and 25/75 wt-%), which are miscible in the bulk (thicknesses: 8nm - 200nm, film thickness was controlled by ellipsometry, film topography by AFM). Both methods are sensitive to different probes; where SHS senses entropy fluctuations BDS measures dipole fluctuations. For BDS measurements, a recently developed nano-structured electrode sample arrangement is employed. By measuring the dynamic glass transition in dependence of the film thickness, SHS showed that the Tg of the whole film was strongly influenced by a nanometer-thick surface layer at the polymer/air interface due to a self-assembling process. Compared to the SHS results the BDS measurements show a completely different behavior. At high temperatures the temperature dependence of the relaxation times of the films follows that of bulk-like PS/PVME obeying the VFT-law. With decreasing temperature the temperature dependence deviates from the VFT to an Arrhenius law where the apparent activation energy decreases with decreasing film thickness. This is the first example were confinement induced changes were observed by BDS for ultra-thin films. All results were analyzed in detail in a comprehensive discussion. T2 - 8th International Discussion Meeting Relaxation in Complex Systems CY - Wisla, Poland DA - 23.07.2017 KW - Ultra thin polymer films PY - 2017 AN - OPUS4-41171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -