Investigations On The Structural And morphological Characterization Of Some Nanocomposite Electrolytes By Digital Image Processing Of Its SEM TEM Images

Abstract

The prime concern of this thesis is an investigation on structural and morphological characterization of some nanocomposite electrolytes by digital image processing of its SEM images. newlineWork was done mainly to resolve the problem of low conductivity of polymer electrolytes at room temperature. Amorphous phase of the polymer electrolytes is the main criteria responsible for the ionic conductivity. Various measures taken for enhancing amorphousity of the polymeric membrane were studied in detail. newlineThe hot press technique was used for the casting of polymer electrolyte membranes. Electrical properties were studied using Impedance Spectroscopy. Structural and morphological characterization of prepared membranes was done by XRD, DSC, FTIR, SEM and digital image processing of SEM images. newlineThin films of solid polymer electrolyte (SPE) and nanocomposite polymer electrolytes were obtained by solvent free hot press technique. Various concentrations of Silver Chloride (AgCl) salt was added into polymer Polyethylene Oxide (PEO) to obtain SPE. Optimum conducting composition (OCC) was determined for SPE. For the preparation of NCPE, SPE(OCC) was used as first phase host and nanosize fillers Fe2O3 and TiO2 as a second phase dispersoid. Ionic conductivity measurement was done by Impedance Spectroscopy using LCR bridge in the frequency range 50Hz-5MHz at room temperature. Activation energy Ea for the ion migration in SPEs and NCPEs was determined from the temperature variation of ionic conductivity study. Ions are the principal charge carriers in polymer electrolytes. Ionic nature of polymeric membrane, SPE and NCPE was determined by ionic transference number calculation. newlineThe structural characterization was carried out by using X-Ray diffraction (XRD) technique which shows that polymer electrolytes SPE and NCPE are semicrystalline in nature. Thermal analysis of SPE and NCPE was done by differential scanning calorimetry (DSC). Decrease of melting endotherm Tm, of SPE and NCPE compared to pure PEO, suggested semicrystalline to amorphous phase transition of polymer PEO. Polymer electrolytes SPE and NCPE are highly complex materials. Vibrational newlineii newlinespectroscopy (FTIR) was used to study conformational changes in polymer matrix and other dissolved species. The surface morphology of SPEs and NCPEs were analyzed by scanning electron microscopy (SEM). SEM micrograph shows the presence of spherulites which is the crystalline phase and it is separated by amorphous boundary. The SEM images of SPE and NCPE were studied using digital image processing. Java based program Image J was used for the qualitative analysis of the SEM image of SPE and NCPE. newline