Polymer-ion-clay interaction based model for ion conduction in intercalation-type polymer nanocomposite

A series of polymer nanocomposite films based on intercalation of (PAN)(8)LiCF(3)SO(3) into the nanometric clay channels of an organomodified clay has been prepared using the standard solution-casting technique. The role of organoclay concentration on polymer-ion interaction, ion-ion interaction, and ion-clay interaction in clay-based nanocomposite films has been analyzed using Fourier transform infrared (FTIR) analysis. Substantial ion dissociation is observed even at a very low clay loading (1-2 wt.%) in the nanocomposites. FTIR results suggest the presence of both uncoordinated CF(3)SO(3) (-) (free-anions) and ion pairs in the nanocomposite evidenced by changes in CF(3)SO(3) (-) symmetry from C3 nu to Cs and marked asymmetry in the profile of degenerate delta(d)(CF(3) (-)) mode. The experimental results suggest a direct correlation of clay-assisted ion dissociation process with variation in conductivity (sigma (dc)) and glass transition temperature (T (g)) as a function of clay concentration. A model has been proposed to explain the observed correlation on the basis of polymer-ion-clay interaction. The proposed scheme of ion transport mechanism appears to be consistent with the experimental observation.