Dr. George Cordoyiannis: High-resolution calorimetry of phase transitions and critical phenomena in soft materials

Pred predavanjem vse udeležence vabimo na čaj!

Povzetek:

      High-resolution calorimetry of phase transitions and critical phenomena in soft materials 

      Dr. George Cordoyiannis, Institut Jožef Stefan & EN FIST Center odličnosti Ljubljana, Slovenija

High-resolution calorimetric techniques are extensively used in order to determine the phase transition behaviour of various systems, ranging from binary liquids, to soft and solid materials. An overview of calorimetric techniques, from the popular differential scanning calorimetry to the high-resolution adiabatic scanning and ac calorimetry, will be given. The relative advantages and disadvantages of these techniques will be discussed. The use of high-resolution calorimetry in the study of phase transitions and critical phenomena will be demonstrated. In a first case, experimental results on the Isotropic to Nematic transition of liquid-crystalline elastomers will be presented. The link between the critical behaviour and the giant thermo-mechanical response of these materials will be explained. In a second case, experimental evidence on the weakly first order character of the Nematic to Smectic A phase transition in liquid crystals will be presented. The results will be discussed within the frame of the Halperin-Ma-Lubensky argument and the formulation proposed by Anisimov and co-workers.