Uniform spheroidal nanoassemblies of magnetite using Tween surfactants: influence of surfactant structure on the morphology and electrochemical performance

摘要: We report solvothermal synthesis of uniform spheroidal nanoassemblies magnetite (Fe3O4) in ethylene glycol medium by using polyethoxylated surfactants viz. Tween 80 and 20, having oleyl (18 carbon) lauryl (12 hydrophobic tails, respectively as structure directing agents. Uniform could be obtained only a narrow range water content the reaction (between 20 50 ppt). Outside this window, heterogeneous assemblies were obtained. Within optimized regime, varying allowed easy modulation assembly dimensions between 200 nm. Under similar synthetic conditions, yielded smaller larger crystalline domain sizes when compared to 20. Dynamic light scattering (DLS) confirmed dimensional uniformity stability these ethanol dispersions. High resolution scanning electron microscopy (HRSEM) showed presence nanoparticles within each while transmission (TEM) revealed densely packed internal architecture assemblies. Powder X-ray diffraction (PXRD) that exclusively composed phase. The size domains present (as determined Scherrer equation) varied from ∼10 25 nm based on conditions employed. Formation small precludes formation requires ≥8 h mature. Magnetic measurements very high saturation magnetization values even at room temperature, well hysteresis behavior for all nanoassemblies. Electrochemical derived samples had highest specific capacitance 75 F g−1 their performance was also more stable cyclic tests materials. This is attributed greater physical over assemblies, indicated SEM studies.