Doping of γ -Fe3O4 magnetic nanoparticles in Pluronic F127/ DMF LLCs phases to tune the structural transitions and rheological behavior

A new rapid microwave-assisted approach has been employed to prepare the gamma-Fe3O4 magnetic nanoparticles (gamma-Fe3O4 MNPs). The formation of spherical gamma-Fe3O4 MNPs with an average size of 45 nm and bandgap of 2.3 eV is confirmed by FESEM and UV-Visible spectroscopy. gamma-Fe3O4 is doped (0.01 wt% and 0.02 wt%) in the lyotropic liquid crystalline (LLC) lamellar phases of Pluronic F127/N,N dimethylformamide (DMF) to prepare the LLC nanocolloids. Polarizing optical microscopy measurement reveals that gamma-Fe3O4 doping does not affect the lamellar LLC structures except 0.02 wt% at 10:90 wt%:wt% system where lamellar to nematic LLC phase transition is observed. Pure LLC phases and nanocolloids are studied for steady and dynamic rheological behavior. LLC phases and LLC nanocolloids possess shear thinning and solid viscoelastic behavior. A complex moduli study of LLCs and LLC nanocolloids is done which indicates the highly elastic strength-based lamellar and nematic phases. Shear-thinning and highly viscoelastic nature of LLCs and LLC nanocolloids have future applications in lubrication, cleaning, cosmetics, and pharmaceutical.