Positron annihilation lifetime studies of free volume in a polymer electrolyte PEO complexed with NH4I

✍ Scribed by B. Haldar; R. M. Singru; S. Chandra

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 168 KB
• Volume: 36
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19980430)36:6<969::aid-polb4>3.0.co;2-b

✦ Synopsis

Positron lifetime spectroscopy has been applied to study the temperature dependence of free-volume properties in a solvent-free polymer-salt complex polyethylene oxide (PEO) doped with ammonium iodide (NH 4 I, with NH / 4 /EO É 0.076) in the temperature range of 298-353 K. The observed lifetime spectra were resolved into three components and the longest lifetime, t 3 , was associated with the pick-off annihilation of ortho-positronium ( o-Ps) trapped by the free volume. The lifetime component, t 3 , and its intensity, I 3 , both showed a significant variation with temperature, which followed a different course in the heating and cooling cycle. Changes in the temperature coefficient of t 3 and I 3 were observed at T É 328 K, the melting point of the sample. This behaviour is correlated to the temperature variation of the electrical conductivity.