Quantitative Thickness Mapping of Dewetting Polymer Bilayers

The study of wetting and dewetting in thin polymer films has many implications for technological applications of polymer films, including dielectric films to control conductivity and colloidal paint systems. We have started to use a novel approach, Near Edge X-ray Absorption Fine Structure (NEXAFS) microscopy, to characterize dewetting in thin polymer films. We have investigated a polystyrene/brominated polystyrene (PS/PBrS) bilayer model system with the Scanning Transmission X-ray Microscope (STXM) at the National Synchrotron Light Source. Our method offers quantitative thickness mapping of all constituent components in these thin polymer films. NEXAFS imaging of polymers has advantages over other forms of microscopy primarily because of its low damage, good chemical sensitivity, and the possibility for quantitative analysis. Figure 1 shows four micrographs of one PS/PBrS bilayer annealed for one week at 170 C.