Chlorophenyl pendant decorated graphene sheet as a potential antimicrobial agent: synthesis and characterization

Facile synthesis of a chlorophenyl decorated graphene (CBG) sheet synthesized by a solvent free green diazotization technique is reported here. The functionalization of the material was supported by various characterization techniques including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR) and thermal analysis. About 15 percent grafting, as determined by XPS and IR spectroscopy, could be achieved under the conditions employed. The CBG sheet was applied for the first time as a potential antibacterial agent on Gram negative bacteria Escherichia coli and Gram positive bacteria Staphylococcus aureus. The antibacterial character was quantified using the MacFarland number technique whereby the volumetric number density of colony forming units was determined. It was also quantified by a Kirby-Bauer test, where the zone formed due to mortality of bacteria caused by chlorine groups attached to the graphene was estimated by a mathematical model. Based on the zone of inhibition created, CBG was found to be more than twice as effective as unmodified graphene and graphene oxide. The synthesis promises to open up a new avenue for the development of chemically converted graphene based antimicrobial agents.