Microstructure of Ni0.5Zn0.5Fe2O4 Nanofiber with Metal Nitrates in Electrospinning Precursor
Department of Advanced Materials Engineering, Gangneung-Wonju National University, Gangneung 25457, Korea
Korea Institute of Civil Engineering and Building Technology, Goyang 10223, Korea
Research Institute for Dental Engineering, Gangneung-Wonju National University, Gangneung 25457, Korea
Author to whom correspondence should be addressed.
Nanomaterials 2020, 10(7), 1344; https://doi.org/10.3390/nano10071344
Received: 15 June 2020 / Revised: 6 July 2020 / Accepted: 7 July 2020 / Published: 9 July 2020
(This article belongs to the Special Issue Nanofibers and Their Applications in Energy, Biomedical Engineering, Environmental Engineering, and Sensing)
Electrospun NiZn ferrite nanofibers have great potential due to their one-dimensional structure and electrical properties, but they have a low reproducibility resulting from many process confounders, so much research effort is needed to achieve optimized process control. For structure control, the viscosity of the precursor solution is a likely parameter. One solution is to use polyvinyl pyrrolidone (PVP) and metal nitrate to obtain the desired viscosity by increasing the nitrate content, even if the polymer content is decreased. Ni0.5Zn0.5Fe2O4 ferrite nanofiber was electrospun with various precursor conditions. Fifteen different precursor solutions, with a content of five polymers and three metal nitrates, were prepared, with precursor solutions composed of Fe(NO3)2·9H2O, Ni(NO3)2·6H2O, Zn(NO3)2·6H2O, polyvinyl pyrrolidone (PVP), and N,N-dimethylmethanamide. The fiber diameter changed from the lowest, of 62.41 nm, to 417.54 nm. This study shows that the average diameter can be controlled using the metal nitrate concentration without a difference in crystal structure when PVP is used. In a 24.0 mmol metal nitrate precursor solution, the process yield was improved to 140% after heat treatment. There was also no significant difference in the crystal structure and morphology. This system reduces the cost of raw materials for electrospinning and increases the process yield of NiZn ferrite nanofibers.