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Silver/polyvinyl alcohol (Ag-PVA) nanocomposite films have been prepared via in situ generation of silver nanoparticles (Ag NPs) by the respective metallic salts and dispersion of preformed Ag NPs (ex situ synthesis) inside polyvinyl alcohol (PVA) and its effect of sensing towards a model protein (bovine serum albumin-BSA) was investigated. The influence of Ag NPs, irrespective of their reduction methodology on the optical and the thermal properties of the PVA, had been investigated using UV-Vis spectrophotometer and differential scanning calorimetry. The absorption peak around 400 nm indicates the surface plasmon resonance response of Ag NPs. The interaction of the dispersed and preformed Ag NPs with the PVA chains is confirmed by the corresponding vibrational signatures of the PVA through Fourier transform infrared spectroscopy (FTIR). The changes in the glass transition and melting temperatures (T g and T m ) of the pure PVA upon the presence of Ag NPs are reported using differential scanning calorimeter (DSC). The sizes of the synthesized Ag NPs are found to be in the range of 200 ± 10 nm for in situ reduction of silver nitrate (AgNO 3 ) and 100 ± 10 nm for the external addition of preformed Ag NPs by sodium borohydride (NaBH 4 ) reduction using scanning electron microscopy (SEM).

In this present work, the solution casting technique was utilized to develop the proton conducting solid biopolymer electrolyte by the complex formation of cellulose acetate (CA) with the ammonium thiocyanate (NH 4 SCN) salt. The crystalline nature and complex formation of CA with different concentrations of NH 4 SCN were investigated using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic techniques. The XRD analysis revealed that the amorphous natures of the CA complex were increased with increase of NH 4 SCN salt concentration, which leads to the higher ionic conductivity. The FTIR analysis confirmed the complex formation between CA and salt matrix. Differential scanning calorimetry (DSC) was used to predict the glass transition temperature (T g ) values, which reveals that the T g value increase with respect to the increase of NH 4 SCN concentration. The electrical conductivity was measured using AC impedance analyzer, which showed that the magnitude of ionic conductivity increases with an increase in salt concentration up to 50CA:50NH 4 SCN. The 50CA:50NH 4 SCN has maximum ionic conductivity value of 3.31 9 10 -3 S cm -1 . Transference number measurement was carried out to investigate the nature of the charge transport species in the polymer electrolyte. The proton battery was constructed with the highest conducting polymer electrolyte 50CA:50NH 4 SCN and its open circuit voltage with load were studied. Hence, the present investigation paves the way for the development of fuel cell and primary proton battery applications.

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