(119g) STRUCTURAL Transitions of MR Fluids in Microgravity

Magnetoreological (MR) fluids display unique properties when subjected to a magnetic field. MR fluids greatly increase their viscosity through rapid formation of chains of dipoles along the direction of the field. Lateral cross-linking of these chains allows the fluid support stress perpendicular to the applied field. Thus, MR fluids undergo a large, fast, and reversible transition from a liquid-like to a solid-like state. This provides and excellent basis in the field of materials engineering for the applications such as actively controlled dampers and actuators.

This poster presents observations and analysis of the NASA experiment, Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions (InSPACE), performed on the International Space Station (ISS). The InSPACE goal is to explore the three-dimensional long-time aggregation kinetics of MR fluids under steady and pulsed magnetic fields. Studies such as these are complicated on earth due to the rapid sedimentation induced by gravity. Video microscopy images taken at different magnetic field strengths are pre-processed to remove background and noise. Fourier methods and particle tracking algorithms are then applied to extract quantitative data, including the suspension microstructure and dynamics. Future work on earth will analyze chain growth with high-speed video microscopy to avoid this sedimentation problem.