Strong Preparation Effects on the Morphology and Gas Transport Properties of Polymer Grafted Nanoparticle Membranes*

Processing conditions and morphology have long been known to dictate the macroscopic properties of polymer nanocomposites due to the incompatibility between hydrophilic nanofillers and hydrophobic polymers. In an attempt to remedy the incompatibility, we chemically grafted the polymer to the nanoparticle and found these polymer grafted nanoparticle (PGN) films yielded significantly high enhancements of gas permeabilities relative to that of the neat polymer. However, in subsequent preliminary data, we were surprised to find that the morphology and property (gas transport) of PGNs are still sensitive to preparation methods. Here, the preparation-morphology-property relationships of polymer grafted nanoparticles are explored. Different conditions including casting methods, choice of solvent, and temperature annealing conditions are investigated for their effects on heterogeneities within morphology using X-ray scattering, and from there, gas transport properties using both the constant-volume / variable-pressure permeation cell and the quartz crystal microbalance.