Conductivities of poly(ethylene oxide) and poly(2-vinyl pyridine) blend

Poly(ethylene oxide) (MW 20,000) and poly(2-vinyl pyridine) (MW 35,000) were blended with LiClO₄ or KSCN through a solution blending process. When the molar ratio of ethylene oxide/Li or K is 10, the blend of poly(ethylene oxide)(80 wt%)/poly(2-vinyl pyridine)(20 wt%) with LiClO₄ or KSCN is a transparent elastomer. The ionic conductivities of these blends are 1.5 × 10^-5 and 8.8 × 10^-5 S/cm at 25°C, respectively. At 30°C the poly(ethylene oxide)(80 wt%)/poly(2-vinyl pyridine)(20 wt%) blends with KSCN at an ethylene oxide/K molar ratio of 10 exhibit an ionic conductivity value of 1.5 × 10^-4 S/cm, a high value for ionic conductive polymers. At an ethylene oxide/Li molar ratio of 15 and a 2-vinyl pyridine/TCNQ molar ratio of 2, the mixed (ionic-electronic) conductivities of poly(ethylene oxide)(80 wt%)/poly(2-vinyl pyridine)(20 wt%) blends are higher than either ionic or electronic conductivities. When the molar ratio of ethylene oxide/Li and 2-vinyl pyridine/TCNQ are 10 and 2, respectively, the mixed (ionic-electronic) conductivities are intermediate between the ionic and electronic conductivities. Differential scanning calorimetry (DSC) shows that LiClO₄ and TCNQ can compatibilize with the PEO/P2VP blend.