How does Nafion Solve Humidity Challenges?
Nafion is a polymer that add/remove select materials, including water vapor, to a gas stream through a first order kinetic reaction (a chemical reaction). Because it’s non-porous, other molecules cannot pass through it. This unique property makes it ideal for medical applications such as removing water vapor from breath samples or adding humidity to gas samples for therapeutic purposes.
What is Nafion?
In technical terms, Nafion is a copolymer of tetrafluoroethylene and a sulfonic acid component. In simpler terms, Nafion is based on a PTFE polymer, very similar to Teflon. It is a synthetically manufactured material that has ion channels. These ion channels transfer select materials, including water and alcohols, through it. It’s non-porous and actually hydrophobic except for the ion channels. Nafion tubing is far superior compared to other membranes you might see in that it is non-porous. It does not have tiny holes, and you can be assured that precious analytes like carbon dioxide, do not pass through it.
Why is Nafion Valued in Medical Devices?
In several medical procedures, the goal is remove water from a gas sample while maintaining the analytes. For example, in capnography, human breath is samples into a capnogram to measure EtCO2. Patient breath contains lots of water vapor and can condense in the equipment, it can lead to inaccurate readings and possibly even premature equipment wear. If a porous material is used for the sample line, some water vapor would be removed, but you run the risk of removing important analytes too. With Nafion™ tubing, only water molecules pass through ion channels and into the surrounding air while all of the carbon dioxide remains in the tube.
Nafion Also Used for Adding Water Vapor to Sample Lines
The same properties that allow water vapor to move from the Nafion tubing to the outside also allow for water vapor to be added to the tubing. For example, therapeutic gasses, such as nitric oxide and oxygen, can be very dry and uncomfortable for patients. By creating high humidity outside Nafion tubing and running dry gas through it, the water molecules pass through ion channels where they are absorbed into the dry gas stream. Because Nafion ion channels are very selective, only water passes through while most contaminants do not.
The unique properties of Nafion make it ideal for solving many humidity challenges.