Ion specificity towards structure-property correlation of poly (ethylene oxide) [PEO]-NH ₄ I and PEO-KBr composite solid polymer electrolyte

Ion conduction mechanism in polymer-salt composite is highly dependent on the optimization of the process parameters. In this investigation, studies on poly (ethylene oxide) [PEO] with different salt viz. ammonium Iodide (NH 4 I) and potassium bromide (KBr) [represented as N-series and K-series respectively] are carried out. Highest ionic conductivity of ~ 10 −4  S cm −1 is observed for PEO-NH 4 I (20%) composite which is found to be the most amorphous. FTIR spectra of N-series are deconvoluted within 3187–3442 cm −1 in order to estimate the percentage of free and contact ions. Number density of free ions is found to increase proportionately with the salt content. Detailed characterization is carried out in view of salt-induced microstructural inhomogeneity. Flexibility of the polymer blend is reflected in several ion-transport parameters like carrier concentration, mobility, etc. Two relaxation times [τ 1 (~ 10 −4  s) and τ 2 (~ 10 −7  s)] as being exhibited in the complex electric modulus clearly illustrate the existence of both amorphous and crystalline regimes within PEO-salt composite.</p

Non-suitability of high-energy (MeV) irradiation for property enhancement of structurally stable poly (ethylene oxide) polyvinylidene fluoride blend bromide composite electrolyte membrane

Application of polymer-salt composite in multifaceted modes viz. as electrolyte, dielectric etc. demands its stability in extreme environmental conditions of high energy radiation zones. The present study reports the behavior of poly (ethylene oxide) PEO] - (polyvinylidene fluoride) PVDF]-KBr composite perturbed by swift heavy ion (SHI) irradiation in the range of tens of MeV. Least conducting PEO-PVDF-KBr is subjected to O7+ ion beam (80MeV) with fluence of 5x10(10) and 5x10(11) ions.cm(-2) respectively. FTIR studies confirm the structural stability of such composite in the mentioned SHI energy regime. SHI perturbation is found to reduce the ionic conductivity of PEO-PVDF composite; however, it could be effectively used as dielectric material for the long term as established from the long-term endurance study (18,500h). Mechanical property evaluation reveals significant increment in nanohardness and Young's modulus of the films perturbed by ion beam. These observations from FTIR, impedance, and XRD are correlated with the morphology of these films