Fluorinert is the trademarked brand name for the line of electronics coolant liquids sold commercially by 3M. It is an electrically insulating, stable fluorocarbon-based fluid, which is used in various cooling applications. It is mainly used for cooling electronics. Different molecular formulations are available with a variety of boiling points, allowing it to be used in "single-phase" applications, where it remains a liquid, or for "two-phase" applications, where the liquid boils to remove additional heat by evaporative cooling. An example of one of the compounds 3M uses is FC-72 (perfluorohexane, C6F14). Perfluorohexane is used for low-temperature heat-transfer applications due to its 56 °C (133 °F) boiling point. Another example is FC-75, perfluoro(2-butyl-tetrahydrofurane). There are 3M fluids that can handle up to 215 °C (419 °F), such as FC-70 (perfluorotripentylamine).
Fluorinert is used in situations where air cannot carry away enough heat, or where airflow is so restricted that some sort of forced pumping is required.
Fluorinert may be harmful if inhaled, and care should be taken to avoid contact with eyes and skin. No health effects are expected by ingestion of Fluorinert, however. Use should be constrained to closed systems and reduced volumes, as fluorinated oils have a very high global-warming potential and a long atmospheric lifetime.
The science-fiction film The Abyss (1989) depicted an experimental liquid-breathing system, in which the use of highly oxygenated Fluorinert enabled a diver to descend to great depths. While several rats were shown actually breathing Fluorinert (this scene was cut in the United Kingdom, as it was seen as animal cruelty), scenes depicting actor Ed Harris using the fluid-breathing apparatus were simulated.