Scanning thermal microscopy (SThM) of polymer blends: Phase separation, localised calorimetric analysis

We are combining thermal analysis with the ability of thermal waves to give sub-surface imageing at sub-micron resolution. Our aim is that the image contrast will be determined by the “modulated-temperature differential scanning calorimetry” peak (M-T DSC) or feature chosen according to the particular component of the specimen that is of interest. As described elsewhere, this will allow us to distinguish in the image between reversible processes such as amorphous-to-glass transitions, from recrystallisations, cure reactions and other irreversible processes within the polymer.The SThM probe gives micron-resolution images whose contrast is determined by spatial variations in thermal properties. Either the temperature at any point is held constant, or we generate and detect evanescent thermal waves whose penetration depth depends on the frequency chosen.The evidence is that a 1 μm-radius probe in air will give a lateral resolution of ca. 200 nm, with a depth detection of a few μm.