Perfluorocarbon Liquids and Application Areas

In Dan Brown's 2009 The Lost Symbol novel, Robert Langdon's decision was stay closed in a tank filled with respirable liquid. Well, how likely is the presence of such a liquid chemical? Respirable liquids (more chemically, perfluorocarbons), which have been shown to be rather dark in the book, seem to be used in diving applications besides existing medical applications.

_{By U.S. Air Force photo by Tech. Sgt. Matt Hecht}

Perfluorocarbons

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Perfluorocarbons are chemical substances used as respirable liquids due to their high oxygen carrier properties. They occur when fluorine atoms come in place of hydrogens in a hydrocarbon. The most common ones are perfluorodecalin, perfluorohexane and perfluorooctyl bromide. One of the most commonly used tetrafluoroethylene, which is gaseous at room temperature, forms polytetrafluoroethylene (teflon) when polymerized. Perfluorocarbon liquids are colorless and odorless as well as have high densities (approximately twice the density of water).

Due to their low intramolecular interactions their viscosities are low compared to liquids with near boiling points. Also, they are miscible with some hydrocarbons (such as hexane), although they are not able to mixed with many solvents (such as ethanol, acetone, chloroform).

Medical Applications

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Although respirable liquid technology by perfluorocarbons is still in experimental processes, they are used in hospitals for liquid ventilation. These applications are partited as total liquid ventilation and partial liquid ventilation. All lungs are filled with fluid in total liquid ventilation technique. Although it is a more advantageous method, it is not used because it requires a complex system (including pump, heater, oxygenator etc.). In partial fluid ventilation, approximately 40% of the total lung capacity is filled with respirable fluid. This technique is used in neonatal intensive care units, in the treatment of respiratory insufficiency in premature infants, and in the expansion of lung volumes. It is also being investigated for use in advanced respiratory insufficiency in adults. In addition, certain perfluorocarbon derivatives such as perfluoro-n-octane, perfluoroethylcyclohexane, perfluorodecalin, perfluorooctylbromide, perfluorophenanthrene, perfluorotributylamine and perfluorotriene-propylamine are used in the stitching of retinal tears. They have low viscosities and have a different refractive index than water. Also, they are highly suited to such surgeries due to their high level of determination.

Deep Dives

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One of the possible uses of perfluorocarbons is deep dives. During deep dives, land animals are faced with the possibility of decompression sickness. Besides, oxygen toxicity (medical condition when people breathe high concentrations of oxygen amd get too much of it into their systems) and nitrogen narcosis (reduction in the ability to think clearly and react quickly, caused by increased air pressure which increases the concentration of nitrogen in bodily tissue and the brain, a special concern of deep-sea divers) are among the effects that may occur. Some gas mixtures can reduce the possibility of decompression sickness but do not completely remove it. In addition, although special atmospheric diving suits remove the problems that can occur on landing, at the exit, and on the surface, they are rather expensive and bulky and have limited use. Respirable liquids are better option at this point. They can be used with more flexible clothes and their risks can be reduced the most. Liquids in the lungs are more advantageous in situations where there is a high pressure change because the internal and external pressures can be balanced. For this reason, there is no need for slowing down movement. However, while respirable liquids seem to be very advantageous for deep dives, their use is only possible with the total ventilation device, due to the low ability to remove carbon dioxide. Breathe freely without an auxiliary machine is not possible for now.

_{JIM Atmospheric Dive Suit at Fremantles Maritime Museum - Photo by Ken Hodge}

References

• ^{Lemal D.M. (2004) “Perspective on fluorocarbon chemistry”}
• ^{Matthews W.H., Kylstra J.A. (1976) “ A fluorocarbon emulsion with a high solubility for CO2”}
• ^{Tawfic Q.A., Kausalya R. (2010) “Liquid ventilation”. Oman medical journal}

 

 

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Posted from my blog with SteemPress : http://kedisteem.press/perfluorocarbon-liquids-and-application-areas/

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