Microstructure, topology and X-ray diffraction in Ag-metal reinforced polymer of polyvinyl alcohol of thin laminates

Abstract

A polymer composite of Ag-metal reinforced polyvinyl alcohol (PVA) is synthesized in shape of thin laminates of 200–300 μm thickness. The process involves a chemical Ag+ dispersion in PVA and in-situ \({\rm Ag}^{+} \to {\rm Ag}\) reduction-reaction with active PVA molecules under hot conditions (with stirring) in water at 60–70°C temperature. The product results in a metal Ag-polymer complex dispersed in the solution. After evaporating part of water, a derived viscous solution is casted (in hot conditions) in shape of a thin laminate in a glass mould. In addition to chemical reducer, active OH-groups (free from H-bonding) in PVA molecules of refreshed surfaces act as head groups to adsorb Ag+ and drive a directional \({\rm Ag}^{+} \to {\rm Ag}\) growth. Short fibrils of Ag-metal thus occur in reaction over the PVA molecules. Casting thin laminates from a liquid sample Ag-PVA allows the fibrils (also the polymer molecules) to align along the surface. Selected Ag-contents up to 5.0 wt.% in Ag-PVA laminates are studied in terms of scanning electron micrograph, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Average size, morphology and aspect ratio (ϕ) vary in Ag-metal depending on the Ag-content. As long Ag-metal fibrils as 2–5 μm, ϕ=35, occur in a sample of 2.0 wt.% Ag. The Ag-metal reflects in two characteristic 3d5/2 and 3d/3/2 XPS bands of 368.3 and 374.1 eV respectively.