Dependence of PEO content in the preparation of Fe3O4/PEO/TMAH ferrofluids and their antibacterial activity

Abstract

This work was conducted to investigate the effects of the polyethylene oxide (PEO) as a template on the structures, functional groups, magnetic properties, and antibacterial activities of Fe3O4/PEO/TMAH ferrofluids. Synthesis of Fe3O4 nanoparticles was carried out by using the co-precipitation method obtained from iron sand. The ferrofluid synthesis was done by coating Fe3O4 nanoparticles with tetramethylammonium hydroxide (TMAH) and dispersed in H2O. Based on the structural analysis, it was known that all samples had a magnetite phase with particle sizes ranging from 7.8 to 10.5 nm. The Fe3O4/PEO/TMAH ferrofluid functional groups presented appropriate bonds of Fe3O4 as a filler, TMAH as a surfactant, and H2O as a liquid carrier. The magnetic characteristics of Fe3O4 nanoparticles and Fe3O4/PEO/TMAH ferrofluids indicated the superparamagnetic state. The saturation magnetization value of Fe3O4 nanoparticles and Fe3O4/PEO/TMAH ferrofluids decreased as increasing the molecular weight of polyethylene oxide ranging from 1000 to 20,000. Furthermore, the antibacterial activities performed by the dilution method identified that increasing the molecular weight of polyethylene oxide increased the antibacterial performance of the Fe3O4/PEO/TMAH ferrofluids against Escherichia coli and Bacillus subtilis.