This study investigated the role of poly-ethylene glycol (PEG) in the microwave synthesis of ZnO (ZPMx) nanorods. The molecular weight of PEG was found to strongly influence the aspect ratio of the synthesized material. The as-prepared ZPMx nanorods were post-grafted onto the surface of GO sheets using 3-amino propyl trimethoxy silane (APTMS) as a cross-linking agent to obtain ZPMx-Si@GO hybrid nanocomposites. Microscopic observations showed that ZPMx nanorods with different aspect ratios were evenly distributed on the surface of the GO sheets. It also showed enhanced thermal and chemical properties. The dependence of the antibacterial behavior on the aspect ratio of the ZPMx nanorods and GO was also investigated. An antibacterial assay was carried out using both the Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli), and Klebsiella pneumonia (K. pneumonia). The results showed that the ZPMx-Si@GO hybrid nanocomposite had an excellent antibacterial property toward the test bacteria compared to pure ZPMx and GO. The synergistic effect of ZPMx and GO resulted in a superior antibacterial activity in ZPMx-Si@GO. Interestingly, the hybrid nanocomposite with a higher ZPMx aspect ratio (ZPM6000-Si@GO) showed excellent inhibition zones with diameters of similar to 3.7, 3.1, and 2.4 cm corresponding to S. aureus, E. coli, and K. pneumonia, respectively. An optical density measurement, as well as the morphological changes in the bacteria, again confirmed the excellent bacterial growth inhibition of ZPM6000-Si@GO. The studies indicated that the ZPMx-Si@GO hybrid nanocomposite is a promising candidate for use in real waste-water disinfection. (C) 2017 Elsevier B.V. All rights reserved.