In situ dose dependent gamma ray irradiated synthesis of PMMA–Ag nanocomposite films for multifunctional applications

Abstract

Herein we report a simple, one pot and rapid gamma-ray irradiation method for the fabrication of PMMA–Ag nanocomposite films for multifunctional applications. The PMMA–Ag composites were synthesised in situ by dose-dependent gamma-ray irradiation followed by film preparation via a compression moulding technique. The composition of the PMMA polymer and the functional groups were determined using Fourier transform infrared spectroscopy (FT-IR) and Raman analysis while UV-vis spectroscopic and X-ray diffraction (XRD) analysis were used to identify the Surface Plasmon Resonance (SPR) bands and crystallinity of the nanocomposite, respectively. Field emission scanning electron microscopy (FESEM) analysis showed that the particles are spherical with an average particle diameter of ∼35 nm, ∼45 nm, ∼50 nm, ∼65 nm, and ∼75 nm as the irradiation dose was increased from 2–6.5 h while energy dispersive spectroscopy (EDS) analysis confirmed the presence of the corresponding elements. Gel permeation chromatography data were used to determine the molecular weight while contact angle studies revealed the surface properties of the composites. The dielectric properties of the composites were found to increase with an increase in the radiation dose. All the as-synthesised films showed good antimicrobial activity against Gram-positive bacteria, Staphylococcus aureus (S. aureus) and Gram-negative bacteria, Escherichia coli (E. coli). The fabricated PMMA–Ag substrate films allowed the detection of the model probe molecule 4-mercaptobenzoic acid (MBA) at concentrations as low as 10⁻⁹ M while the Raman enhancement factor was found to be as high as ∼10⁴.