Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions - 3 (InSPACE-3) - 05.06.15
Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions - 3 (InSPACE-3) studies magnetic colloidal mixtures under the influence of various magnetic fields. A magnetic colloidal fluid, a type of smart fluid, contains materials which solidify within the liquid when a magnetic field is applied to it, thus changing the physical properties of the liquid as a whole. Conducting these experiments on board the International Space Station (ISS) allows scientists to examine in detail the network and arrangement of the 'frozen' solid structures unaffected by the force of gravity which can deform them on Earth.
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Eric M. Furst, Ph.D., University of Delaware, Newark, DE, United States
Robert D. Green, Glenn Research Center, Cleveland, OH, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
March 2011 - March 2014
Previous ISS Missions
InSPACE, the precursor to InSPACE-2 was performed on ISS Expeditions 6, 7, 12 and 13.
- InSPACE-3 studies the fundamental behavior of magnetic colloidal fluids under the influence of various magnetic fields. Observations of the microscopic structures yields a better understanding of the interplay of magnetic, surface, repulsion forces, and particle shape between particles in magnetically responsive fluids.
- These fluids are classified as smart materials which transition to a solid-like state by the formation and cross-linking of microstructures in the presence of a magnetic field. On Earth, these materials are used for vibration damping systems that can be turned on or off.
- This technology has promise to improve the ability to design structures, such as bridges and buildings, to better withstand earthquake forces.
The use of external fields to control the microstructure of colloidal suspensions has long been recognized as a powerful means for tailoring the mechanical, optical and electronic properties of materials. Magnetorheological (MR) suspensions, in particular, provide a striking example. These normally stable fluids undergo a dynamic transition to a solid within milliseconds after the application of an external magnetic field. They are also important models for developing methods of bottom-up fabrication of micro- and nano-structured materials and devices using field-directed self-assembly.
Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions-2 (InSPACE-2) experiments focused on the structure of magnetically-polarizable particle suspensions over long times in steady (DC) and pulsed magnetic fields. In pulsed fields especially, the long-time kinetics of the suspension micro-structural coarsening provided new and important results. The InSPACE-2 experiments were the first to yield information on the full, three-dimensional aggregation process over timescales much longer than those that are accessible on the ground, which are limited by catastrophic sedimentation. Furthermore, the experiments identified a novel and intriguing dynamic instability in which the suspension microstructures were observed to buckle at specific field frequencies and field strengths. For InSPACE-3, we will investigate the effect of particle shape on the micro-structural evolution of MR suspensions. Recent ground-based experiments demonstrate a startling effect that particle shape has on the interactions of dipolar chains and the resulting suspension microstructure. Specifically, we will investigate suspensions of paramagnetic ellipsoid-shaped particles. In combination with the results of InSPACE-2, we hypothesize that particle shape will dramatically alter the aggregation kinetics, microstructures and microscopic mechanics. This will potentially lead to the ability to engineer enhanced properties of these suspensions, including suppression of the lateral aggregation in magnetorheological fluid-based electromechanical devices or the ability to create new colloidal materials through field-directed self-assembly.
The quick phase-shifting property of magnetic colloidal fluids makes them potentially useful for devices such as optical interfaces, active noise, and vibration dampers inside spacecrafts. Future uses could include robotics, energy-transfer devices such as clutches, and other control systems.
The work has application to directed self-assembly of crystalline structures from particles that may eventually allow creation of new nano-materials fabricated from nanoparticle building blocks, with potential applications in medicine, energy storage, chemical separations, and catalysis. Magnetic colloidal fluid technology is currently being used for shock absorbers in racecars and sport cars. This technology is expanding to include making large-scale building foundation stabilizers for areas prone to earthquakes.
InSPACE-3 will be conducted inside the MSG work volume. The fluid sample in the vial assembly must be uniformly mixed prior to test operations. Thirty-six tests will be performed, two or three per day. The Vial Assemblies may be reused indefinitely after restoring an even distribution to the particles within the fluid. Video downlink will be monitored on the ground during testing and provided to the PI as desired. Sample return of the Vial Assemblies is not required. Video imagery will be stored on 72 Mini-DVCAM tapes and 36 Hi-8 tapes for later return to the ground for more complete analysis.
The crew will install the hardware into the MSG and as part of that uniformly distribute the particles in the fluid of the first Vial Assembly prior to installation in the hardware. Two DVCAM and one Hi-8 tape will be loaded into the video recorders in the video drawer. The crew member will next focus each optical train onto the particles in the center of the vial. A run is started by setting the current per the test matrix and then setting the pulse frequency of the current. Both are simple adjustments of dial pots by the crew while observing digital displays of the values of each. Note that the current level controls the strength of the magnetic field applied to the MR fluid. A Field of View sweep and a focus sweep are performed right away with each optical train and then again about 20 minutes later. The experiment will run autonomously with ground monitoring for the next two to three hours. Another FOV sweep and focus sweep for each optical train is performed prior to removing the magnetic field from the vial by setting the current to zero. Another run may be started with the same vial assembly after remixing the particles in the fluid, or a different vial assembly may be used. Upon completion of all testing, the hardware is removed from the MSG.
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ISS Research Project-InSPACE-3
NASA Image: ISS016E021067 - Expedition 16 Commander Peggy Whitson works with the InSPACE-2 (Investigating the Structure of Paramagnetic Aggregates from Colloidial Emulsions-2) experiment in the Microgravity Science Glovebox (MSG) in the U.S. Laboratory/Destiny.
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InSPACE-2 MR fluid microstructure chains forming under a 2 Hz pulsed magnetic field. Image courtesy of NASA.
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Increment 18 astronaut Mike Fincke setting up the InSPACE-2 hardware in the Microgravity Science Glovebox (MSG)
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InSPACE-3 Vial Assembly. Image courtesy of Glenn Research Center.
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NASA Image: ISS032E005652 - Side view of an InSPACE-3 (Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions 3) vial (VA3-005 3:1 B). Photo taken during an inspection for clumps and bubbles.
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