Synthesis and properties of new intercalates Eu xZrSe 1.95

Abstract

Plasticised samples of PEO 30:PC m:ZnX 2 (PC = propylene carbonate; m = 3.3 and 6.7; X = Cl, Br, I) were prepared using 20% and 33% w w of propylene carbonate with respect to PEO. None of the films were tacky and, although they were quite flexible compared to films prepared without PC, all of them were mechanically strong. The addition of propylene carbonate dramatically improved the conductivity of all samples; for m = 3.3 the conductivity increased by about three orders of magnitude and for m = 6.7 the conductivity increased by about four orders of magnitude. The conductivity of the PEO 30:PC 6.7:ZnCl 2 sample was 1.1 × 10 −5 S cm −1 at 25 °C, compared with 7 × 10 −7 S cm −1 for the PEO 30:PC 3.3:ZnCl 2 sample and 7.4 × 10 −10 S cm −1 for the non-plasticised sample, and attained a conductivity of 10 −4 S cm −1 at about 60 °C. However, a gradual loss of conductivity was noticed with prolonged storage of films in the glove box at room temperature. After 2 months storage, the conductivity at 25 °C of the PEO 30:PC 6.7:ZnCl 2 sample had dropped to 2.5 × 10 −6 S cm −1. Differential Scanning Calorimetry results showed that the glass transition temperature, in the samples in which it was detectable, had been significantly lowered by the addition of propylene carbonate. The PEO 30:PC 6.7:ZnCl 2 sample had a T g of −46 °C compared with −12 °C for the non-plasticised PEO 30:ZnCl 2 sample. Some glass transitions could not be detected, however, which suggests that the amorphous phase may not be perfectly homogeneous. The DSC results also revealed that the amount of crystalline PEO present in the samples had been reduced by the addition of propylene carbonate.