Controlling the processing of co-precipitated magnetic bacterial cellulose/iron oxide nanocomposites

Hybrid nanocomposites of bacterial cellulose (BC) and magnetic iron oxide nanoparticles (NPs) are of interest due to their potential for novel applications. Magnetic NPs are typically synthesized by co-precipitation since it is facile, enabling control of their size and distribution. This work investigates the effect of using different starting reactants (Fe(II) and Fe(III) salts) in the fabrication and control of the properties of BC/iron oxide nanocomposites. It was found that the choices of starting reactants are not important for synthesizing NPs outside of the BC networks. However, the starting reactants do affect the formation of NPs when they are synthesized in the BC network. Significant differences in the morphologies, sizes, crystal structures, and magnetic phases of NPs occurs when in this environment. The nanopores of BC networks in some instances force the aggregation of the NPs, either within the pores, or on the surfaces of the fibrils. Nanocomposites synthesized from Fe(II) sulfate and Fe(III) chloride were found to exhibit the highest magnetization. These nanocomposites have potential for flexible sensors, actuators, or electromagnetic shielding. Nanocomposites from Fe(II) acetate and Fe(III) chloride, though exhibiting lower magnetization, preserve a porous structure. Thus, they have potential as adsorbents or for wound healing applications. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).