High Performance Photopyroelectric Calorimetry of Liquids

A review of the main photopyroelectric (PPE) calorimetric techniques proposed in the last years for accurate measurements of dynamic thermal parameters (thermal effusivity and thermal diffusivity) of liquids is presented. The possibilities offered by the two PPE detection configurations (“back” and “front”) are analyzed, and the information contained in the amplitude and phase of the PPE signal are compared. A study of the accuracy of the investigations when using the frequency or thickness scan method is also made. Some basic applications concerning high-resolution measurements of thermal diffusivity and effusivity of some “special” liquid samples (isotopic liquid mixtures, magnetic nanofluids, liquid foodstuffs) are described.