(207a) Characterization of Polyelectrolyte Membranes Loaded with in-Situ Grown Metal-Oxide Nanoparticles

Formation of nanocomposites by in-situ growth of metal-oxide nanoparticles (MONP) in polyelectrolyte membranes (PEM) has been quite appealing for several potential applications such as: fuel cells, water purification, and protective barriers against chemical warfare agents (CWA). PEM micro-structure can serve as capping agents for the nanoparticles and depending on PEM conditions (humidity, degree of swelling, solvents present) in-situ grown nanoparticles can adopt various shapes and sizes. Among several potential applications this paper is focused on PEM-MONP composites for self-detoxifying composite PEM barriers against CWA. These PEM have self-assembled interconnected hydrophilic and hydrophobic sub-domains that provide perm-selective properties and good transport of water vapor, while acting as a barrier against dangerous substances. PEM ion-exchange capabilities have been used for the in-situ formation of MONP within PEM at various conditions to observe the influence of PEM micro-structure on MONP growth. In addition, transport properties of PEM-MONP composites were analyzed by sorption and permeation experiments with water and chemical warfare surrogates (CWS). Sorption experiments results are compared with mathematical models and show the impact that MONP have on transport properties of PEM. Transmission and scanning transmission electron microscopy (TEM/STEM) were used to observe MONP growth and particle size distribution within PEM. X-ray diffraction (XRD) was used to analyze crystalline structure of MONP. Various spectroscopic techniques (NMR, XPS, EDS) were used to: assess chemical states of MONP within PEM, analyze permeation of CWS, uniformity of MONP distribution within PEM at various conditions.