Lignin-containing cellulose nanofibers made with microwave-aid green solvent treatment for magnetic fluid stabilization.

Lignin-containing cellulose nanofibers (LCNFs), prepared from energy cane bagasse (ECB) using microwave-assisted natural deep eutectic solvent (MW-NADES) pretreatment combined with microfluidization, are utilized as stabilizing agents for magnetic particles (MNPs) in magnetorheological fluids (MRFs). The as-prepared LCNFs helped suspend negatively charged MNPs in MRFs effectively due to the presence of physically entangled network of LCNFs and the electrostatic repulsion between LCNFs and MNPs. Consequently, the presence of LCNFs increased the viscosity, yield stress and dynamic moduli of MRFs within the entire magnetic field range (0-1 T). Moreover, the as-developed LCNF-MRFs exhibited superior magnetorheological properties, i.e., widely controllable viscosity, yield stress and dynamic moduli, rapid magnetic response, good reversibility and outstanding cycling stability. This work demonstrates the sustainable, ultrafast production of LCNFs from cellulosic biomass using MW-NADES for MRF stabilization, paving the way for the development of high-performance, and eco-friendly MRFs.