Synthesis of High Aspect Ratio Iron Oxide Nanoparticles Using Water in Oil Microemulsion

High aspect ratios maghemite of iron oxide nanoparticles were prepared using water in oil microemulsions. A four component microemulsion system with cationic HTAB, n-butanol, noctane, and salt solution was used. Precipitations of iron oxide were initiated by mixing a microemulsion system containing Fe2+ with another microemulsion system containing OH-. The resulting particles were characterized using XRD, AGM and TEM. The XRD result showed the formation of maghemite. TEM showed that the average length of needle shaped particles increased from 28 nm up to 42 nm as the aging time was increased from 4 to 24 hours while the average diameter spherical particle remained at around 8 nm. The AGM confirmed that the particles are superparamagnetic.