Spherulite Crystallization in Poly(ethylene oxide)–Silica Nanocomposites. Retardation of Growth Rates through Reduced Molecular Mobility

The spherulitic crystallization of nanocomposites of poly(ethylene oxide) (PEO) and silica nano-sphere filler particles was investigated using optical microscopy and differential scanning calorimetry (DSC). It was found that spherulite growth rates were retarded by the presence of the silica nano-particles. This was interpreted in terms of reduced molecular mobility caused by either geometric constraints in the confined small volumes between particles, or by an increase of the interfacial surface area at which polymer chains were pinned. There was an indication of lowering of final crystallinity and increase of amorphous content for heavily filled higher molecular weight polymer. Implications for conductivities of PEO when used as a solid electrolyte in applications such as batteries are considered.