Permeation dynamics of dimethyl methylphosphonate through polyelectrolyte composite membranes by in-situ Raman spectroscopy

Reliable measurement of permeability of membranes with respect of different chemical compounds is of paramount importance for the design of novel materials for selective separations, protective barriers against chemical warfare agents and toxic industrial chemicals. An original in-situ Raman spectroscopy experimental setup is devised to measure the dynamics of permeation of toxins with example of diffusion of dimethyl methylphosphonate (DMMP), a nerve agent surrogate, across polyelectrolyte composite membranes. Efficiency of the proposed method is demonstrated on two types of commercial membranes, Nafion 117 and Nexar MD9200, modified with metal oxide nanoparticles. It was found that loading membranes with ZnO nanoparticles significantly reduces agent permeation, enhancing its protective capabilities against hazardous substances. The proposed methodology can be adopted and applied for characterization of permeability of other types of CWAs, their simulants, and other chemicals through polymeric membranes of different origin.