Effect of salt concentration on the properties of poly[oxymethylene–oligo(oxyethylene)]/Mg(ClO4)2 polymer electrolytes

Abstract

The thermal and electrochemical properties of mixtures of poly[oxymethylene–oligo(oxyethylene)](POMOE, oxymethylene-linked PEG400) with magnesium perchlorate have been investigated. The mixtures formed non-crystalline, homogeneous solutions at room temperature. Glass-transition temperatures were measured over the concentration (c) range 0.1–3.0 g (kg polymer)^–1(O/Mg = 240–8), and were found to increase as the salt concentration was increased with a linear dependence of 1/T_g on c. Conductivities were measured over the concentration range 0.1–1.5 mol kg^–1(O/Mg = 240–16) and the temperature range 20–80 °C: maximum conductivity at 27 °C was ca. 4 × 10^–5S cm^–1 at a salt concentration of 0.6 mol kg^–1(O/Mg≈40). Comparison is made with results for poly(oxyethylene)-based polymer electrolytes, and with POMOE–LiClO₄ electrolytes.