The average and local glass transition temperatures (Tg s) and physical aging behavior of various confined polymers were studied in order to gain an understanding of these surface/interface effects and their propagation into the polymer. Using a novel multilayer/fluorescence method, the Tgs of layers at the free surface, substrate-polymer interface, and at known distances away from the interfaces of poly(methyl methacrylate) (PMMA) films supported on silica were measured. Since attractive hydrogen-bonding interactions are present, it was shown that perturbations to Tg can propagate over length scales of several hundred nanometers and overwhelm the free surface effect, thereby leading to an increase in the average Tg across the film.Silica nanospheres (colloidal silica in methyl ethyl ketone, Nissan Chemical Industries, reported diameter of 10-15 nm) ... Resulting films contained less than 0.2 wt% dye relative to polymer and were at least 1 I¼m in thickness (Tencor P10 anbsp;...
|Title||:||The Glass Transition and Physical Aging Behavior of Polymer Nanocomposites Studied Via Fluorescence|
|Publisher||:||ProQuest - 2008|