FIG. 5.

The average water content removed in 8 repeat measurements from Nafion membranes during a thermogravimetric analysis simulating the drying conditions with a dry nitrogen purge used in typical neutron imaging experiments. The 1 σ uncertainty is calculated from the standard deviation of the 8 measurements. To determine the dry weight of the Nafion, the chamber was subsequently evacuated (70 kPa vacuum pressure) and the temperature was elevated to 105 °C for 40 h. The initial water content varied with environmental temperature and humidity, but was on average λ = (3.64 ± 0.27) mol H₂O/mol ${\text{SO}}_3^{-}$.