MICROGRAVITY SCIENCE EXPERIMENTS

Structural Studies of Colloidal Suspensions

Objective: Understanding the structures of colliods may allow scientists to manipulate their physical properties - a process called "colloidal engineering" - for the manufacture of novel materials and products. Colloid research may even improve the processing of known products for the enhancement of desirable properties.

Description: The second Colloidal Gelation experiment will further colloid research through the study of three kinds of colloids: binary alloy colloids, a colloid possessing particles of different sizes; colloid polymers, a colloid that in addition to possessing spherical particles also possesses long, chain-like molecules; and fractal colloid aggregates, colliods possessing repeating structural patterns or networks.

In orbit, all three types of colloid samples will be mixed to distribute the suspended particles and then allowed to sit for several days. During this interval, particles in the samples will organize themselves in crystal-like arrangements. Laser light will be used to gather structural information about the samples. The light will be directed at the samples and scatter as it is reflected off the surface of the crystalline structures, revealing the placement of particles in the colloids. Observations of the properties resulting from particular structures can then be made. With this information, researchers will develop models to predict the structures and properties of different kinds of colloids. The ability to predict a material's characteristics could result in decreased product development time and may lead to more efficient manufacturing. Industries using semiconductors, electro-optics, ceramics, and composites are among those that may benefit from colloid research.