Binary Colloidal Alloy Test Low Gravity Phase Kinetics-1-Product Shelf Life (BCAT-KP1-Shelf Life) - 11.22.16
Binary Colloidal Alloy Test - Kinetics Platform-Shelf Life (BCAT-KP-1-Shelf Life) enables industrial scientists to investigate the physics of colloid phase changes in microgravity. Colloids are suspensions of small particles evenly distributed throughout a solution, and examples range from detergent to milk and are greatly affected by gravity on Earth. A greater understanding of colloid kinetics could lead to products with longer shelf lives, benefiting consumers and industries on Earth. Science Results for Everyone
Information Pending Experiment Details
Matthew Lynch, Ph.D., Procter and Gamble, Cincinnati, OH, United States
William V. Meyer, Ph.D., Glenn Research Center, Cleveland, OH, United States
ZIN Technologies Incorporated, Cleveland, OH, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
National Laboratory (NL)
Earth Benefits, Scientific Discovery
ISS Expedition Duration
September 2013 - September 2015
- This application describes the development and deployment of a colloidal investigation platform, the Binary Colloidal Alloy Test Low Gravity Phase Kinetics Platform (BCAT-KP). The applicants identify characterization of phase kinetics for emulsions in a low gravity environment as a major application area, citing the low gravity environment as an idealized condition in which to examine attractive colloidal systems for optimal product shelf life. The application described a device with 10 sample chambers that allows parametric studies of variations in particle size and functionalization in generating phase maps. Specific solvent mixtures to allow buoyant matrix, similar to those corresponding to ground studies, are utilized along with non-buoyancy-matching solvents to greatly expand the knowledgebase of phase transitions in colloids. Mixtures are photgraphed using fluorescence and a Nikon digital camera currently mounted in WORF. Alternate imaging modalities are not explored.
- The formation of ordered phases in colloidal suspensions is profoundly affected by gravity via sedimentation processes. Chaikin and Russel demonstrated this effect in space experiments; their experiments explored the simplest of all entropic transitions, the hard-sphere liquid-solid phase transition. There are many ways to understand the reasons for the difficulties posed by gravity. Sedimentation causes particles to fall so rapidly that there is insufficient time for particles to explore the full phase space of positions and velocities that are required for thermodynamic assembly processes. In a different vein, a substantial particle concentration gradient arises in the earthbound sample. In the given samples the gravitational height, h = kT/ΔρVg, ranges from a few microns for the case of polystyrene in water to a fraction of a micron for some of the other particles considered. Here k is the Boltzmann constant, T is temperature, Δρ is the density difference between the particles and the background fluid, V is the particle volume, and g is the gravitational acceleration on the Earth’s surface. This height is typically much smaller than the sample size. In addition, the shear forces of fluid flow, due to the sedimentation of particles, are often sufficient to breakup crystals that are forming thermodynamically not allowing the scaling and understanding to a wider variety of compositions.
- One reason Procter and Gamble is involved in this proposal is their interest in understanding phase separation kinetics of colloids, which is masked by gravity on Earth. The small blobs that form and grow in microgravity, instead of the simple top and bottom phase seen on Earth, allow the kinetics of this process to be recorded in microgravity. The scientific findings allow one to believe that additional results from having this data available can, and likely will, lead to more efficient/improved product formulations which are less expensive to produce and/or provide longer shelf life. For a product like Downy, which sells about $4B worth of product a year, even a small 1% savings in production costs or allowing a longer shelf life provides a significant return on the investment. P&G, which is represented by one of the research scientists on this proposal, will spend $10M this year on research to address product shelf life problems. The results of this work can impact far more than fabric softener.
- The other colloidal samples described have similar potential but have a more long-range commercialization potential through development of new suspension materials and their Intellectual Property protection. Their material formulations and suspension intellectual property have resulted in several patents, and could lead to new companies and license revenues for their organizations. The opportunity to establish new models and formulations through low gravity investigations cannot be replicated or achieved on Earth and provide unique commercialization potential to these inventor/investigators and their organizations.
For the proposed phase separation samples, the objective is to measure phase separation rates in microgravity (u-g) to develop an underlying theory for predicting product shelf life (P & G) and for colloidal material engineering having scientific and commercial interest. The first set of samples investigate colloidal collapse [irreversible separation] which occurs on Earth and must be mitigated with expensive particle additives. The solution to this problem is a series of non-optimal trades between more particles to jam system (expensive) versus greater attraction properties to gel system having undesired rheological properties. Researchers intend to photograph initially randomized colloid samples to determine their resulting structure over time. Theory tells that one can adjust the rate of phase separation by changing the amount of polymer in the solution of polymethyl methacrylate (PMMA) spheres. Doing this adjusts the depletion attraction force between particles. This gives a window into the underlying physics that is not open on Earth where only a top and bottom phase is visible. The results are of particular relevance to product manufacture and production designs for the pharmaceutical, food and cleaning industries (in terms of shelf life and mechanical and thermodynamic properties).
Binary Colloid Alloy Test (BCAT) investigation helps scientists characterize the underlying physics of colloidal materials, including how particles clump and sink inside a liquid. Colloidal mixtures form small blobs in microgravity, rather than the clear distinction between top and bottom that occurs in the presence of gravity on Earth. Examining how these clumps form and grow can provide unique insight into the physics of this process. The BCAT hardware has potential for commercial use in space, and the investigation also lays a foundation for research in nanotechnology and nano-mechanical systems in microgravity.
Understanding the physics of colloidal materials, including how they separate into distinct layers, can help scientists develop more stable colloidal mixtures that have longer shelf lives. But the kinetics of this process are masked by gravity on Earth, making it difficult to study even with powerful computer simulations. The BCAT investigations allow scientists to monitor colloidal materials’ behavior over time, which will shed light on the physics involved as well as provide data to improve computer models. Ultimately, improved colloidal materials may last longer and cost less to produce, which will benefit a wide range of consumers and industries.
Operational Requirements and Protocols
Decadal Survey Recommendations
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NASA Image: ISS040E013856 - NASA astronaut Reid Wiseman conducts a session with the Binary Colloidal Alloy Test (BCAT) experiment.
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NASA Image: ISS038E031151 - Close-up view of a BCAT-KP hardware setup in the Japanese Experiment Module (JEM).
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