Hydrostatic behaviour of highly inert Fomblin and Halocarbon fluids as pressure-transmitting media in high-pressure experiments

A pressure-transmitting medium (PTM) plays an important role in diamond anvil cell (DAC) experiments as it ensures that the sample is exposed to hydrostatic pressure. Although PTMs that are liquids under ambient conditions are the easiest to handle and load, the selection of chemically inert liquid media with established hydrostatic properties is limited. To widen the choice of highly inert PTMs for high-pressure experiments, the hydrostatic behaviours of Fomblin Z60, Fomblin Z25, Fomblin Y LVAC 06/6 and Halocarbon Oil 11-14 were investigated. The ruby fluorescence method was used to monitor the evolution of pressure gradients across the DAC sample chamber during compression and decompression. Fomblin Z60 and Fomblin Z25 perfluoropolyethers, which are hydrostatic to 1.7 and 1.5 GPa, respectively, exhibited the best hydrostatic performance, followed by Halocarbon Oil 11-14 with a limit of 1.2 GPa, whereas the non-hydrostatic behaviour of Fomblin Y LVAC 06/6 was observed above only 0.6 GPa.