Ag nanoparticles induced modification in microhardness of polyvinyl alcohol

Abstract

Silver (Ag) nanoparticles play a significant role in nanomaterials science and technology due to many peculiarities. One of the main characteristic of Ag nanoparticles is the occurrence of surface plasmon resonance (SPR) due to the collective oscillation of free electrons in visible region. Due to this distinctive feature Ag nanoparticles have numerous applications such as in catalysis, surface enhanced Raman spectroscopy, photonics, solar cells etc. In the present work, no additional stabilizing agent has been used. The characteristic SPR peak appears at around 405 nm in UV-Visible absorption spectra of PVA-Ag nanocomposite films, thereby confirming the nanocomposite formation. The synthesized nanocomposite films were structurally characterized using fourier transform infrared (FTIR) and Raman spectroscopy. FTIR spectra of PVA-Ag nanocomposite film indicates that PVA matrix is modified by Ag nanoparticles which is in agreement with the results obtained using Raman spectroscopy. TEM as well as FE-SEM micrographs reveal that Ag nanoparticles are mostly spherical in shape. The knoop microhardness number of the nanocomposites was found to increase from 2.4 Kgf/mm 2 for PVA to 12.1 kgf/mm 2 for PVA-Ag nanocomposite film loaded with 0.062 wt% Ag nanoparticles.

Enhancement of infrared absorption through a patterned thin film of magnetic field and spin-coating directed self-assembly of gold nanoparticle stabilised ferrofluid emulsion

“…The vibrational mode observed at 1707 cm −1 can be attributed C O vibrations, 66,67 while the ∼1729 cm −1 was ascribed to C O vibration associated with acetate molecules within the PVA (88% hydrolysed). 70 At the centre of the substrate ( r = 0), there was a relative increase in the intensity of the C O (1707 cm −1 ) vibrational mode compared to the C O (1729 cm −1 ) vibrational mode. However, the intensity of both peaks decreased in all spectra obtained from locations on the thin film at a high radial distance ( r > 7 mm from the centre of the film).…”

“…These angles may be particular to the geometry of the thin film generated in this study because the greater grazing angle on the chains with a given height might cast a shadow of one strip on to the other, limiting the overall exposure of light on the material. 70 Another possibility is that incident wave backscattering increases at greater grazing angles. 73 Therefore, the optical waves interacted poorly with the thin-film pattern and glanced at the highest grazing angle.…”