In this project, bilayer films consisting of PDMS, silicone oil, and CrO2 were designed. This project required careful design of the films’ geometry for testing and for actuation. Design parameters that were taken into consideration include the length, width, and thickness of each layer of the magnetic films. Different dimensions were designed for different spontaneous curvature profiles. Additionally, the concentration of silicone oil had to be tested and designed for different desired curvatures. The curvature of the magnetic films is dependent on the film thickness. Therefore, the film thickness had to be designed to achieve different curvatures for different geometry. The objectives of this project involved characterizing the contraction and curvature of the magnetic films and design of 3D geometry for light actuation. Characterizing the behavior of the films was necessary to be able to design 3D geometry. The second objective required using the knowledge of material behavior to design geometry with desired modes of actuation. The two modes of actuation designed in this project were crawling and enclosing. This project involved scientific understanding of magnetization, beam theory, material science, and magnetic and internal forces.
The material behavior was tested with careful measurements of contraction and curvature. Magnetic films were created with different dimensions, silicone oil concentration, and thicknesses. The dimensions were measured before and after contraction using a ruler. The curvatures were measured after contracture using precise radius reference sheets. The 3D geometry was modeled, but has not yet been created or tested.