Study and Control of Thermal Transport in Complex Fluids

Resumo

In this thesis, we propose the study of heat transport in liquids as a novel approach to the study of the dynamic structure of liquids. We focus our attention on the thermal conductivity, which is highly sensitive to changes in the dynamic nature of the whole systems. This strategy was used to characterize different fluids, which leads to the discovery of new phenomenology in these systems, with unforeseen applications in areas such important as energy storage or biology. We focus our research in two different projects. First, we study the effect of dissolving different solutes into the tetrahedral structure of liquid water. This shows the sensitivity of the thermal conductivity to changes in the microscopic arrangement, demonstrating the formation of supramolecular structures within the liquid. On the other hand, we perform a systematic study of the thermal transport in ILs, which shows a large thermal conductivity difference between liquid and solid phases. This suggests their use as thermal regulator in different technological aplications. Moreover, we have improved these systems by using azobenzene based compouds, which allow an active control of the thermal conductivity by an external stimulus, in this case the application of UV light.