(415c) Glass Transition Temperature, Viscosity and Dynamics of Thin Polymeric Films in a Leveling Experiment

The glass transition temperature and viscosity of thin polymeric films during thermal annealing of nano-structures are measured by x-ray scattering and numerical modeling. Films of poly(methyl methacrylate) (PMMA) are patterned via nanoimprint lithography into dense structured gratings and heated from below while small angle x-ray scattering data is collected in a transmission geometry. The leveling dynamics as a function of time and temperature is used to measure a viscosity coefficient, from Stokes' equations, and the glass transition temperature. The inclusion of the antiplastizier tris(2-chloropropyl) phosphate (TCPP) is obtained from the differences in viscosity and glass transition temperature. A un-symmetric radial basis function approach is used to simulate different geometries and conditions. As the TCPP concentration increases, or as the pattern size decreases, the leveling flow temperature decreases. However, the leveling rate is less dependent on size as TCPP is introduced in the polymer. The proposed methodology provides a route to extract rheological information of nano-scale polymeric films directly. An extension for linear viscoelasticity is proposed, where G' and G'' are related to the glass transition temperature.