טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentCohen Yehoshua
SubjectDynamics of Planar Magnetic Nanopropellers
DepartmentDepartment of Applied Mathematics
Supervisors Professor Alexander Leshansky
Dr. Konstantin Morozov


Abstract

Controlled steering of micro-/nanopropellers by rotating magnetic field is a promising technology for targeted delivery in various biomedical applications. In these applications magnetized chiral (helical) nanostructures actuated by rotating magnetic field propel unidirectionally through a fluidic environment similar to a rotating corkscrew. It was shown recently that geometrically achiral magnetized objects, such as planar V-shape objects, can propel as well. However, unidirectional steering is not guaranteed due to their high symmetry.

In the first part of this work we study the dynamics of planar V-shaped propellers actuated by a conically rotating magnetic field provided by superimposing the constant magnetic field along the axis of the uniform rotating field. We demonstrate that adding the constant field reduces the symmetry and can, in fact, lead to unidirectional propulsion of planar and in-plane magnetized objects, that exhibit no net propulsion in an in-plane rotating field.

The second part of the work is devoted to a theoretical study of superparamagnetic nanopropellers. Such nanobots do not possess remanent magnetization, but are instantly magnetized by the applied magnetic field. Magnetic properties of such polarized structures are governed by the geometry-dependent magnetic susceptibility tensor χ. We study effective susceptibility of planar V- and arc-shaped structures and demonstrate that they do not yield net propulsion due to high symmetry.