The present study reports the antibacterial properties of flower-shaped ZnO (FZnO) microstructures and its comparison with that of hexagon-shaped bulk ZnO (BZnO) nanostructures. The samples are prepared successfully by wet chemical method and the surface morphologies, structures and size of the ZnO samples are characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), BET adsorption isotherm, and Photoluminescence (PL) Spectroscopy. The SEM and TEM images of the sample have confirmed flower-shaped structure of the ZnO. The materials are also analyzed by using an innovative tool called Lacunarity, a nonlinear dynamical (NLD) tool for proper understanding of the inherent surface properties of the particles formed, comparing the results estimated with the BET results obtained, thereby confirming our proposition to use it as an important parameter in predictive models. In this new approach, geometry of the surface structure is being associated with biological properties, in order to come up with easier ways to identify materials for any such applications where rich surface structure is desired. The photocatalytic activity of the flower-shaped material is carried out to find out its optical properties as another marker for confirming the antimicrobial activities. It has been reported for the first time that the prominent antibacterial activities are favoured by the FZnO microstructure having lesser Lacunarity, significantly better than its bulk counterpart, for inhibiting gram negative-Escherichia coli microorganism. Nanotechnology, at present, pertains to creation of useful materials, devices, and systems through appropriate manipulation of matter. A significant number of researchers have reported that formation of ZnO nanostructures in different shapes, such as, nanorod, nanoplates, nanowire 1 , flower-shaped ZnO microstructures 2 , etc. In the present work, two important attributes, capping and molarity, are used to control the particle size and their agglomeration 3. It is reported in W Yu et al. (2016), that photo-generated electrons in ZnO are much lighter than their corresponding holes, which indicates that it belongs to the n-type semiconductor 4. This result paves the way for obtaining excitation energy of electrons in ZnO that determines its optical property. ZnO materials are good inhibitors of microorganisms, and it is believed that this activity is enhanced in case of ZnO due to its high surface morphology. The capped ZnO usually shows up higher antibacterial activity than the uncapped one 5. In the present work, flower-shaped ZnO (FZnO) microstructures in PVP matrix and uncapped hexagon-shaped bulk ZnO (BZnO) nanostructures are synthesized for the study of their antimicrobial properties. The as-prepared samples are characterized by X-ray diffraction (XRD) 6 , Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) to find their size and shape 7,8. Further, the FZnO are characterized by UV-spectra, Photoluminescence (PL) Spec...
