Localized thermal analysis using a miniaturized resistive probe

TLDR

The authors introduce a differential, miniaturized resistive probe that enables spatially localized calorimetric analysis and paves the way for scanning calorimetric microscopy, while noting that quantitative interpretation requires mathematical modeling. The technique uses a differential arrangement with an active probe that simultaneously serves as a localized heat source and thermometer to perform spatially resolved calorimetry. The probe detected glass transitions, melting, recrystallization, and decomposition in polymer volumes of a few μm³, and these events matched those observed with conventional calorimetry.

Abstract

We describe a novel thermal characterization technique based on a differential arrangement, which achieves spatially localized calorimetric analysis. It involves the use of an active probe which acts both as a highly localized heat source and a thermometer. This ability opens the way for the implementation of scanning calorimetric microscopy where image contrast will be created from thermal analysis data. For a number of polymers we have recorded events such as glass transitions, meltings, recrystallizations and thermal decomposition within volumes of material estimated at a few μm3. The data obtained are compared with those obtained from conventional calorimetry and the events registered in both cases are found to match. For a full quantitative analysis of the results obtained, mathematical modelling of the operation of the technique, taking account of physical and other changes in materials, is required.