Wacław Grzybkowski

Copper transport properties in polymer electrolytes based on poly(ethylene oxide) and poly(acrylonitrile)

Abstract Transport properties of copper salts were studied in a solvent-free polymer electrolyte PEO–Cu(CF 3 SO 3 ) 2 (where PEO is poly(ethylene oxide)) as well as in gel-type polymer electrolytes: polymer–solvent–CuX 2 (where X=Cl − , Br − or CF 3 SO 3 − , polymer is PEO or poly(acrylonitrile) (PAN), solvent is dimethylsulfoxide (DMSO), sulfolane or propylene carbonate). Generally, low values of the cationic transference numbers ( T + ≈0.02–0.08) for the polymer electrolytes were obtained. However, in the systems based on PAN plasticised with DMSO, the T + value increases significantly ( T + ≈0.1–0.4); the highest value is reached in the system containing an excess of the Br − anions (PAN–DMSO–CuX 2 –KBr, T + =0.4).

Molar volumes and heat capacities of electrolytes and ions in N,N-dimethylformamide

Densities and heat capacities of various 1:1 and higher-charged electrolytes have been measured in N,N-dimethylformamide (DMF) at 25 degrees C using a series-connected flow densimeter and Picker calorimeter. Standard molar volumes V (o) and isobaric heat capacities C p (o) derived from these data were split into their ionic contributions using the tetraphenylphosphonium tetraphenylborate (TPTB) reference electrolyte assumption. The values so obtained have enabled a meaningful separation of the effects of cationic size and charge for the first time in a nonaqueous solvent. As in water, V (o)(M (n+) ) values in DMF are markedly more negative for higher-charged cations due to increasing electrostriction of the solvent. In contrast, ionic charge has a much smaller effect on C p (o)(M (n+) ) in DMF than in water. Ionic volumes in DMF show the expected dependence on size but those of small monatomic monovalent cations and anions imply a significant difference in accessibility of the electron donor and acceptor sites on the DMF molecule. Ionic heat capacities in DMF show a relatively weak dependence on ionic size that, when corrected for charge, is opposite to that in water. Both V (o)(R 4N (+)) and C p (o)(R 4N (+)) in DMF show the usual linear dependence on carbon number but differ from their values in aqueous solution due to the absence of hydrophobic interactions in DMF.

Apparent molar volumes of divalent transition metal chlorides and perchlorates in dimethyl sulfoxide solutions

Densities and apparent molar volumes for DMSO solutions of manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) perchlorates and chlorides are reported. The limiting partial molar volumes of the hexakis-(DMSO) cations are derived and discussed in terms of the ligand field effects. The differences between volumetric properties of DMSO solutions of perchlorates and chlorides are interpreted in terms of formation of the respective chloride-complexes of the divalent transition metal cations.