April 2014 - Completion of Procter and Gamble (P&G) Advanced Colloids Experiment (ACE) Sample (ACE-M-1) Operations on International Space Station (ISS): The tenth and last ACE-M-1 sample was started on April 4, 2014, and successfully completed on April 7, in the Light Microscopy Module (LMM) on the ISS. The Principal Investigator, and P&G Principal Scientist Dr. Matthew Lynch, will present the experiment findings as the Keynote Speaker at the American Society for Gravitational and Space Research (ASGSR) annual meeting. The data is expected to guide near term product improvements at P&G (e.g., longer shelf-life, higher concentrations, improved product formulation, better stabilizers). These improvements will lead to products that are more environmentally friendly (products that last longer, take less packaging, and have lower transportation impact). Flight data from ACE-M-1 will also be used in the design of the first 3-dimen-sional confocal ACE study scheduled for mid-2016.
The experiment used two sizes of particles (2.2 and 1.8 micron diameter) and depletion attraction to form a stabilized gel. By using two sizes of particles, this polydisperse system is more like an industrial system (which is often not monodisperse). The different particle sizes were dyed to fluoresce at different colors and they were each observed at 63X, 40X and 20X. In post processing, the images will be over-laid and “false” colored to tag the different particles sizes. The two images below show the final data points after 72 hours of sample evolution.
Advanced Colloids Experiment-Microscopy (ACE-M)
Advanced Colloids Experiment-Microscopy-1 (ACE-M-1) studies the behavior of microscopic particles in gels and creams. Many consumer products are colloidal mixtures with stabilizers added to make them last longer. But eventually, particles still clump together and sink to the bottom in a process known as coarsening which can spoil a product. The International Space Station is an ideal location to study the physics of coarsening which could lead to manufacturing longer lasting products.
Sometimes it's hard to tell a gas from a liquid. Advanced Colloids Experiment-Microscopy-2 (ACE-M-2) observes the microscopic behavior of liquids and gases separating from each other. The investigation examines the behavior of model (colloid rich) liquids and model (colloid poor) gases near the critical point, or the point at which there is no distinct boundary between the two phases. ACE-M-2 uses a new microscope to record micro-scale events on short time scales, while previous experiments observed large-scale behavior over many weeks. Liquids and gases of the same material usually have different densities, so they would behave differently under the influence of gravity, making the microgravity environment of the International Space Station ideal for these experiments.
The Advanced Colloids Experiment-Microscopy-3 (ACE-M-3) experiment involves the design and assembly of complex three-dimensional structures from small particles suspended within a fluid medium. These so-called “self-assembled colloidal structures”, are vital to the design of advanced optical materials. In the microgravity environment, insight will be provided into the relation between particle shape, crystal symmetry, and structure: a fundamental issue in condensed matter science.
Advanced Colloids Experiment-Heated (ACE-H)
The Advanced Colloids Experiment-Heated-1 (ACE-H-1) experiment examines densely packed microscopic spheres, or colloidal mixtures, to study their transition from ordered crystals into disordered glass. The particles are fluorescent and change size in different temperatures, so scientists are able to see how they move and change forms as they are heated and cooled. Studying particle interactions without the influence of gravity improves the ability of scientists to understand how increasing disorder in a crystal material affects its freezing, melting, aging and structural integrity.
Colloidal mixtures, which are small particles suspended in a fluid, are found in everyday household products, fuels and even foods. They can spoil when solid particles clump together or sink inside the liquid and form distinct layers. Advanced Colloids Experiment-Heated-2 (ACE-H-2) examines the Casimir effect, a function of quantum mechanics that creates a small force of attraction, and heat to determine how colloidal mixtures form clumps and solid structures.
Advanced Colloids Experiment-Temperature (ACE-T)
Currently manifested for flight on SpX-8, scheduled for November 2015.
Currently working on preliminary science for a 2019 launch.