COMSOL simulation of CNT assembly in an epoxy matrix under static magnetic fields for polymer nanocomposite applications

Organization of carbon nanotubes (CNTs) within epoxy matrices can be effectively achieved using magnetic field application. In our previous experimental work, multi-walled CNTs were magnetized, diazotized, and magnetically aligned to form aligned CNT-epoxy composites. While effective toughness improvement was experimentally observed with small CNT addition, more understanding about magnetic assembly of CNTs is desired, to effectively complete CNT assembly before the epoxy cures and also to avoid re-agglomeration of CNTs. In this work, assembly behaviors of ellipsoid particles, that simulate CNT bundles, in a fluid domain, that simulates the epoxy matrix, under the static magnetic field are being studied. Higher ellipsoid aspect ratio was observed to be effective to decrease the magnetic assembly time, while some ellipsoid lower aspect ratio and larger original ellipsoid separate distance combination prevented their magnetic assembly. When assembly is achieved, the assembly time was observed to be much smaller (<0.1 second) than the currently dedicated assembly time in our experiments (~10s of minutes). Further studies with more ellipsoids, varying ellipsoid positions, and increasing magnetic field strength are planned in future.