Quantitative Compositional Mapping of Phase Separation in Thin Polymer Films

Experiments and theoretical work on spinodal decomposition of thin films of binary polymer blends indicate large changes in phase behavior and dynamics relative to the bulk behavior due to the complex interactions of the polymer-polymer, polymer-air, and polymer-substrate interfaces. Currently used techniques are able to sense growing domain sizes but are not always able to sense local two and three dimensional variations within domains. We are using a new characterization approach to these thin films utilizing the Scanning Transmission X-ray Microscope (STXM) at beamline XIA at the National Synchrotron Light Source (NSLS)². We extract component thickness maps of each polymer in a sample region. This allows for quantitative investigation of the dynamics of polymer phase separation and should allow the determination of important parameters affecting the domain formation in these thin films.