Test MethodInfrared spectroscopic measurement of water permeability in polymer films exposed to liquid water

The details of a method for measuring the water vapor transport rate through polymer films utilizing Fourier transform infrared spectroscopy (FTIR) are given. Water flows across one side of the membrane and a nitrogen sweep gas carries the water vapor into the flow-through cell of the spectrometer for measurement. The method was used to test two polymers that have literature values and four new polymers. The resulting FTIR data was analyzed with a partial least-squares method. Experimentally the method is easy to apply and very accurate.