Phase separation and Remixing in Polymer Blends and Solutions - from bulk to thin films

Phase separation and remixing are important transformations in the processing and application of polymer blends and polymer solutions. Modulated temperature DSC (MTDSC) proves to be very valuable for studying phase separation and remixing, for determining whether the systems are homogeneous or heterogeneous (from the glass transition(s)), to get an idea of the phase compositions, and for building phase or state diagrams and determining demixing or remixing kinetics. The origin of the contribution of the demixing-remixing phenomena to the MTDSC heat capacity signal will be discussed. For studying the thermoresponsive behavior of 100-nm thin films of polymer blends, AC chip calorimetry was successfully explored. It permits studying the influence of the substrate surface chemistry and the film thickness on the state diagram and the process kinetics. Combining these modern thermal analysis techniques, giving information on bulk and thin film thermal behavior, with hot-stage atomic force microscopy and nano-thermal analysis, provides a detailed insight in the material behavior. The paper will give some highlights of our recent work in these fields.