Defect probing using positron annihilation and dielectric spectroscopy of PVA/Al thin films

Abstract

The Casting method is used to produce nano-composite polymeric thin films (PVA/Al) with varied aluminum content (x=0.0, 0.04, 0.08, 0.1wt.%). The morphology of thin films is examined by Scanning electron microscopy (SEM), and it is used to approve the homogenous nature of the prepared thin films and to determine the grain size. The obtained nano-composite thin films reveal an enhancement of dielectric properties by adding the nano-filler to polymeric matrix. Also, the Differential Scanning Calorimetry (DSC) studies show an increase in the glass temperature (Tg) by increasing Al content. The microstructure changes of the prepared PVA/Al NPs composite films are investigated using the positron annihilation lifetime (PAL) and Doppler broadening (DB) techniques. The interactions between the PVA and Al NPs through the formation of hydrogen bonding modify the size and concentration of the free volume holes.