Quantifying the Diffusion of a Fluid through Membranes by Remote Detection MRI

We present a method to measure self-diffusion across membranes without the need for concentration or pressure gradients. Hyperpolarized xenon in combination with remote detection of NMR allows the measurement of membrane permeation, even in the gas phase. The resulting images allow quantification of the amount of fluid diffused through the membrane, and represent an alternative, potentially more precise way of measuring a membrane diffusion coefficient. The use of remote detection of NMR allows for non-invasive signal encoding coupled to sensitive detection, making this approach ideal for the study of diffusion in intact devices such as fuel cells or separation systems