Binary Colloidal Alloy Test - Kinetics Platform (BCAT-KP) - 02.05.14
ISS Science for Everyone
Science Objectives for Everyone
The BCAT-KP experiment will provide a platform for material and industrial scientists to investigate colloid phase changes to help develop new colloidal materials and formulations with unique properties. These properties will provide innovative applications from new liquid crystals to consumer goods having longer shelf lives and more versatile uses. Examples of colloids are detergent, fabric softener, milk, paint, clouds and blood.
Science Results for Everyone
ZIN Technologies Incorporated, Cleveland, OH, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
National Laboratory (NL)
ISS Expedition Duration
September 2013 - September 2014
Previous ISS Missions
This BCAT builds and expands upon previous BCAT design heritage including:
- BCAT-3 launched January 2004 on Progress 13 (Flight 13P)
- BCAT-4 launched March 11, 2008 on Flight 1 J/A
- BCAT-5 launched 8/28/2009 on Fligh 17A
- BCAT-6 launched 2/24/2011 on Flight ULF5
- BCAT-C1 launched 7/211/2012 on Flight HTV-3
- 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. Specific chemical entities are not identified in this proposal, but the co-investigators have broad experience in this area and the integration of a commercial partner (P&G) suggests many of the experimental studies are of a proprietary nature. The application described a device with 10 sample chambers that will allow 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, will be utilized along with non-buoyancy-matching solvents to greatly expand the knowledgebase of phase transitions in colloids. Mixtures will be images 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 our 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 we consider. 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 our 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 resulting scientific insites that result 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. These new materials and formulations are commercialized through licenses or through start-up companies as evidenced by the prolific patent portfolios of our Co-Investigators. Their material formulations and suspension intellectual property have resulted in several patents, 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.
The BCAT-KP investigation and SGM series objectives are to provide a macro colloidal phase kinetic platform allowing fast turnaround for colloidal investigations to examine equilibrium conditions that result in colloidal crystallization, melting and self-organization. This BCAT-KP will provide colloidal investigators recurring opportunities for each 3 month ISS Increment giving the U.S. its first fast turnaround physical science platform offered through CASIS. These colloidal systems and the ability to support a series of multiple samples allows for parametric investigation of colloidal suspension structures enabling characterization of phase maps that cannot be produced on Earth at size scales of commercial and scientific interest. The equilibrium state and progression toward that will be different for different types of samples. Phase separation samples may ultimately evolve into two distinct phases. While this happens quickly on Earth, the gradual evolution to this state in microgravity is especially important when it comes to understanding and designing new emulsions for longer product shelf life or for new material development, this coarsening behavior and the rate of coarsening of attractive colloid systems is of special interest providing valuable data to design new material emulsions.
Series 2 will run Dr. Cheng’s thin platelet samples as described below and the second set of Dr. Lu’s critical point samples. Dr. Cheng will run his second set in the 3rd series and another set of 5 samples will be available for other investigators. It is envisioned that progressive BCAT-KP series of investigations will be offered to the existing and future investigators.
For the proposed phase separation samples, our objective is to measure phase separation rates in microgravity (u-g) to develop underlying theory for predicting product shelf life (P & G) and for colloidal material engineering having scientific and commercial interest. The first set of samples will 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. We intend to photograph initially randomized colloid samples to determine their resulting structure over time. Theory tells us that we 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 us a window into the underlying physics that is not open to us 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) experiments lays the foundation for nanotechnology and nanomechanical systems in space.
Succinctly put, a fundamental understanding of the underlying physics that is needed to stabilize everyday commercial products may enable product formulations with enhanced performance and stability, while simultaneously lowering the cost of manufacture. That is, for commercial products, we can look at the rate of phase separation as a function of the vesicle concentration. Adding more vesicles inhibits phase separation and increases product shelf live, but at a price. It costs more to make the product and we are adding material for reasons other than which the product was created. Through the understanding and development of material formulation models we can determine the underlying physics of a product, and enhance its performance while decreasing its manufacturing cost (a win-win situation).
The work with ellipsoidal and platelet particles addresses geometry dependence of glasses and liquid, where our scientists expect that work with non-spherical particles will lead to the discovery of new liquid crystalline phases and in general to new condensed phases of matter with various commercial applications. Traditional questions about the relative packing fractions, which crystallization phase is manifested, and the passing from one phase to the other, may be studied in these systems without the perturbing effects of sedimentation and gravitational jamming. With regard to the commercial potential of the proposed crystal samples, colloidal nucleation experiments seek an understanding of the most fundamental liquid/solid transition. Growth of ordered colloidal phases has attracted interest in a number of areas, e.g. ceramics, composites, optical filters and photonic band gap materials. Being able to test the enhanced strength and directional properties of ellipsoidal crystals that may only grow in microgravity will tell us if it is worth pursuing microgravity production capability.
In addition to the commercialization potential and application of the information generated from the sample investigations, there is commercial potential of the microgravity colloidal or material sample hardware itself. P&G spent a considerable amount of time with LANL and UCSB with high-powered computers to try and model the behavior that is being explored during the BCAT investigation with no considerable success. This opportunity will provide empirical information to track and record the evolution of a colloidal sample behavior over time to anchor these models and verify predictions and new product solutions and performance to design expectations.
We believe this commercial value coupled with the ability to quickly fly samples in a cost competitive manner and on a continuous basis provides a commercially viable service to many industries developing or utilizing particle additives in their products. We believe that hardware such as the BCAT-KP coupled with a reduction in launch cost and cycle times has tremendous commercial potential.
ZIN along with our team believe there is commercial interest for soft matter investigators and commercial providers of these materials to pay for ISS investigation opportunities using the BCAT-KP capability.
BCAT consists of a set of ten small samples of colloidal particles. The BCAT samples are each contained within a small case the size of a school textbook. The experiment requires a crew member to set up the experiment using a handrail/seat track configuration, ISS Laptop and the Kodak 760 or Nikon D2Sx camera to take digital photographs of the samples at close range. The pictures are down-linked to investigators on the ground for analysis. (see figure above)
The current plan for this experiment is to conduct it over a 7 or 14-day session, each of which can be run incrementally and require a minimum amount of crew time due to powering the digital camera with the new AC power available through the inverter to be available in 2012; a third session to mix and photograph all 10 samples and then a fourth session, prior to the increment completion and bringing the samples down for the next increment set of hardware, to photograph all ten samples which is slotted to take a minimal amount of crew time. As such, new information will undoubtedly be learned, and the nature of the experiments conducted will evolve to take advantage of this new information.
Session 1: Set up hardware, take baseline photos of all ten samples; homogenize samples 6-10 then samples 9 and 10, then automatically photograph sample 1 (using EarthKAM software on laptop) every hour for 7 days. Perform sample 1 daily status check each day. After seven-day run, perform crystal search/photography on 6-10. Homogenize sample 2, automatically photograph sample 2 (using EarthKAM software on laptop) every hour for 7 days. Perform sample 1 daily status check each day. After seven-day run, perform crystal search/photography on 6-10. If necessary, tear down after operations are complete but keeping setup intact is preferred to save crew time.
Session 2: Set up hardware, homogenize samples 3, 4 and 5 one at a time then automatically photograph each sample (using EarthKAM software on laptop) every hour for 14 days each. Perform Crystal Check and Photography procedures on 6-10 if crystals not found/photographed in Session 1. If necessary, tear down after operations are complete but keeping setup intact is preferred to save crew time.
Session 3: Homogenize and photograph samples 1-10 (using EarthKAM software on laptop) and stow sample module for six months. The experiment is torn down after operations are complete.
Session 4: At at end of increment after homogenization, manually photograph Ssamples 1 through 10. Re-stow sample module and tear down after operations are complete