Modeling and experimentation of nanofluids for heat transport and storage applications

The study focuses on molecular dynamics simulations using LAMMPS to investigate the properties of functionalized graphene in aqueous solution. The main goal is to analyse the TBR trend with the degree of functionalization, as well as to compare the analogous simulation results with experimental data obtained by the Institute Lumiere in Lyon using Ultra fast time-resolved optical spectroscopy. Graphene is known for its high thermal conductivity and its thermal properties are very much dependent on the environment around it. Through functionalization, the graphene surface is chemically modified by attaching different functional groups, in particular hydroxyl groups, and this changes its intrinsic properties, such as thermal conductivity and its interactions with water molecules. These interactions can be manipulated by modifying the functionalization level, and its impact on the thermal conductivity of the material can then be observed. This work extends the assessment of TBR to include an examination of the density profiles and incorporates insights into the wettability of functionalized graphene. These supplementary analyses give a glimpse of how functional groups influence the material’s affinity to water, suggesting how much the graphene is hydrophilic or hydrophobic. The study of density profiles, in particular, addresses the water molecule distribution around the graphene sheet, revealing the way functional groups could impact solvation and aggregation tendencies. An integral part of this study was an internship lasting two months at the Institute Lumiere in Lyon, which enabled a deeper knowledge of practical experimental methodologies. The practice obtained during the internship, where the experimental methods were explored to study the thermal properties of nanoparticles, complemented the simulation work and provided a wider understanding of graphene behavior in aqueous solutions.