Highly localized thermal, mechanical, and spectroscopic characterization of polymers using miniaturized thermal probes

In this article, we demonstrate the versatility of use of cantilever-type r esistive thermal probes. The probes used are of two kinds, Wollaston wire p robes and batch-microfabricated probes. Both types of probe can be operated in two modes: a passive mode of operation whereby the probe acts as a temp erature sensor, and an active mode whereby the probe acts also as a highly localized heat source. We present data that demonstrate the characterizatio n of some composite polymeric samples. In particular, the combination of sc anning thermal microscopy with localized thermomechanometry (or localized t hermomechanical analysis, L-TMA) shows promise. Comparison with data from c onventional bulk differential scanning calorimetry shows that inhomogeneiti es within materials that cannot be detected using conventional bulk thermal methods are revealed by L-TMA, We also describe a new mode of thermal imag ing, scanning thermal expansion microscopy. Finally, we outline progress to wards the development of localized Fourier transform infrared spectroscopy: here the probe, in this case operated in the temperature-sensing mode, det ects the photothermal response of a specimen exposed to the beam and heated thereby. (C) 2000 American Vacuum Society. [S0734-211X(00)11303-4].