Magnetic Field Directed Self-Assembly of Colloidal Nanoparticles via Extreme Field Gradients of Magnetic Recording Media
Date of Award
Open Access Dissertation
Physics and Astronomy
Thomas M. Crawford
Magnetic nanoparticles have been extensively studied over the last half century and continue to sustain interest due to their potential use in different fields. This research explores Magnetic Field Directed Self-Assembly of magnetic nanoparticles using a magnetic disk drive. The magnetic fields generated by the bits in a magnetic disk drive have rapidly changing field gradients that can self-assemble magnetic nanoparticles into various shapes. We demonstrate the ability to record and read field gradients on a commercial disk drive medium and to use monodisperse iron oxide nanoparticles to achieve self-assembly. We use image analysis techniques to quantify parameters related to self-assembly, and real-time optical measurements to monitor changes in optical diffraction signal as nanoparticles self-assemble into two-dimensional parallel arrays. In addition, we compare our experimental results to Langevin dynamics simulations and show that small changes to the magnetic or colloidal force change the self-assembly from ordered hexatic phase assemblies to disordered features. Our results demonstrate the ability to precisely control and tune the self-assembly of magnetic nanoparticles to achieve features with sub-200 nm resolution for various applications.
Mohtasebzadeh, A. R.(2022). Magnetic Field Directed Self-Assembly of Colloidal Nanoparticles via Extreme Field Gradients of Magnetic Recording Media. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/7126