Gamma irradiation effects on the structural, thermal and electricalconductivity properties of ceric ammonium nitrate (CAN) doped HPMC based biopolymer electrolyte films

A solid biopolymer electrolytes (BEs) based on hydroxypropyl methylcellulose (HPMC) doped with different concentrations of ceric ammonium nitrate (NH4)2Ce(NO3)6 (CAN) were prepared by solution cast method. Different techniques has been employed to investigate the effects of structural, thermal and ionic conductivity behavior of these polymer electrolyte films upon gamma irradiation with different doses of 20, 60 and 100 kGy. The dissolution of the salt into the polymer host and the structural properties of pure and CAN (0.5% 2%) (wt. %) complexed HPMC polymer electrolyte films before and after irradiation was confirmed by X – ray diffraction (XRD) studies. XRD results revealed that the amorphous domains of HPMC polymer matrix was increased with increase in the salt concentration and with the gamma dose. The percentage of crystallanityis found to be high in pristine unirradiated HPMC films. The variation of film morphology was examined by scanning electron microscopy (SEM). Thermal properties of these polymer electrolyte films before and after irradiation were studied using differential scanning calorimetry (DSC). The results revealed that the presence of CAN in the polymer matrix increases the melting temperature, however it is observed that the total enthalpy of fusion (∆Hf) is maximum for unirradiated pristine HPMC films. Direct current (dc) conductivity was measured in the temperature range of 313–383K. The temperature-dependent of HPMC based BEs system conductivity data obeys Arrhenius relationship. Conductivity enhancement in these BEs is caused not only by the increase in the concentration of CAN but also by the increase in mobility and diffusion coefficient of ions and with increasing gamma dose.