Macroscopic non-equilibrium thermodynamics in dynamic calorimetry

TL;DR

This paper explores what dynamic calorimetric experiments truly measure by applying macroscopic non-equilibrium thermodynamics, focusing on complex heat capacity and entropy production, offering new insights into irreversible processes during experiments.

Contribution

It introduces a thermodynamic phenomenological framework to interpret dynamic calorimetry, emphasizing the role of non-equilibrium processes and complex heat capacity.

Findings

Clarifies the physical meaning of frequency-dependent complex heat capacity.

Highlights the role of entropy production in irreversible processes during calorimetry.

Provides a thermodynamic basis for analyzing macro-systems undergoing transformations.

Abstract

What is really measured in dynamic calorimetric experiments is still an open question. This paper is devoted to this question, which can be usefully envisaged by means of macroscopic non-equilibrium thermodynamics. From the pioneer work of De Donder on chemical reactions and with other authors along the 20th century, the question is tackled under an historical point of view. A special attention is paid about the notions of frequency dependent complex heat capacity and entropy production due to irreversible processes occurring during an experiment. This phenomenological approach based on thermodynamics, not widely spread in the literature of calorimetry, could open significant perspectives on the study of macro-systems undergoing physico-chemical transformations probed by dynamic calorimetry.