Monday, April 4, 2016

Experimental feature: Liquid crystals in space

Microscopic detail of liquid crystal islands tethered like necklaces when an external
electric field is applied near the very thin film surface. Caption and Image Credit:
Liquid Crystal Physics Group / University of Colorado Boulder
The crew aboard the International Space Station perform hundreds of experiments each year in nearly all fields of science. There is so much that goes un-reported in mainstream news. Because of this, Orbital Velocity makes an attempt to feature some of these studies.

OASIS: Observation and Analysis of Smectic Islands In Space

Since liquid crystals are used in display screens on TVs, clocks and laptops, scientists want to understand how microgravity affects these crystals' ability to appear as both a liquid and a solid.

Liquid crystals flow like a liquid, but contain molecules that are arranged in a specific pattern—like a crystal. In addition to being used in LCDs, they form in naturally occurring things, such as soap bubbles. The OASIS experiment looks at these bubbles
Expedition 47 Commander Tim Kopra works to install the OASIS experiment in the
Microgravity Science Glovebox. Photo Credit: NASA

When you look at bubble, you usually see iridescent colors on its surface. This layer of color—liquid crystals—has a thickness that varies and changes when water flows back and forth over the surface. It is the thicker place on the bubble that scientists are looking at. They look like islands and are referred to as smectic islands.

On ISS, the experiment will produce these smectic islands on bubbles. The thickness could be as thin as 6 nanometers. For comparison, the thickness of human hair is 60,000 nanometers.

In normal gravity, when the islands become larger, they slide to the bottom of the bubble and "layer" up. But that doesn't happen in space.
A detailed look at the OASIS Experiment Module. Image Credit: NASA

This is the first experiment of its kind done in microgravity. Investigators hope to use the information found to make better displays in space—potentially using the technology as a heads-up display in spacesuit helmets.

By better understanding the physics behind these liquid crystals, improvements can be made on Earth-bound LCD screens. Such improvements include improved color contrasts and response times.

This experiment was sent to ISS on April 14, 2015 aboard a SpaceX Dragon cargo ship. Crews conduct the study inside the Microgravity Science Glovebox, which is located inside the U.S. Destiny laboratory. The study is being lead by the University of Colorado Boulder.