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Insights into the Water Transport Mechanism in Polymeric Membranes from Neutron Scattering



Edwin P. Chan, Bradley R. Frieberg, Jacob Daniel Tarver, Madhusudan Tyagi, WenXu Zhnag, Bryan Coughlin, Christopher M. Stafford, Abhishek Roy, Steve Rosenberg, Christopher L. Soles


Polymeric membranes are ubiquitous in a number of transport ap- plications including gas separation, water desalination, solid state batteries and fuel cells. The permeability and selectivity of these membranes are intimately linked to the structure and dynamics of the pores within these materials. In this contribution, we study the structure as well as the water and polymer dynamics of several polymeric membranes using small-angle and quasi-elastic neutron scat- tering. We demonstrate that on the scale of a few nanometers, water appears to diffuse through a water desalination membrane at a rate comparable to bulk water, while water diffuses at a rate that is a factor of two slower in an anion exchange membrane. These results are reconciled in terms the structure of the desalination membrane which contains a tortuous porous network with pores approximately a nanometer in dimensions whereas the anion exchange membrane is a swollen polymer network without such channels. These findings have important implications in understanding the underlying trans- port mechanisms that differentiate different types of polymeric membranes.
Proceedings of the National Academy of Sciences


membranes, polymers, transport, neutron scattering, reverse-osmosis, anion-exchange


Chan, E. , Frieberg, B. , , J. , Tyagi, M. , Zhnag, W. , Coughlin, B. , Stafford, C. , Roy, A. , Rosenberg, S. and Soles, C. (2020), Insights into the Water Transport Mechanism in Polymeric Membranes from Neutron Scattering, Proceedings of the National Academy of Sciences, [online], (Accessed April 22, 2024)
Created February 5, 2020, Updated April 25, 2020