The proposed research will focus on the dynamics of polymer blend films and polymer blend films containing nanoparticles. Control of film properties, such as hardness and permeability, are greatly complicated by the simultaneous occurrence of phase separation and wetting. Using lateral and depth profiling techniques, the phase evolution and wetting behavior of blends with a critical composition will be investigated for films as thin as 10 nm, ca. radius of gyration. By controlling domain size and spacing, membranes with monodisperse, submicron pores will be prepared. The phase and wetting dynamics of off-critical blends will be studied to gain control over film stability, interfacial area between phases, and wetting structure. New evolutionary pathways are anticipated yielding better insight into phase separation, wetting and capillary fluctuations in confined spaces. The second project will investigate how inert fillers, in particular mobile nanoparticles, modify the rate and morphology of phase separation in polymer blend films. After evaluating silica nanoparticle diffusion and wetting, the effect of particle size, concentration and wettability on domain evolution and morphology will be evaluated using the experimental techniques developed for the previous study as well as new techniques for depth and lateral profiling of the nanoparticles within the film. The proposed research is important because thin polymer films containing multiple components are critical to many technologies including photolithography, adhesives, and displays. In particular, experimental studies of polymer blends containing filler greatly lag both theory and commercial applications. Fundamental studies will be complimented by studies of commercial filler-polymer films of interest to the automotive coatings industry. Outreach programs including a second cable TV show on polymers, demonstrations at public and private elementary schools as well as high school teacher training will continue as will training of undergraduate students.
