SEAgel
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SEAgel (Safe Emulsion Agar gel) is one of a class of high-tech foam materials known as aerogels. It is an excellent thermal insulator and among the least dense solids known; in fact, SEAgel has a density that is approximately equal to that of air. SEAgel was invented by Robert Morrison at the Lawrence Livermore National Laboratory in 1992. SEAgel is made of agar, a carbohydrate material that comes from kelp and red algae, and contains only forty to fifty milligrams of material per cubic centimeter of solid (in other words, it has a density of 40-50 mg/cm3). SEAgel is also completely biodegradable, as it is made entirely of biological material.
Initially, SEAgel starts out as a gelatin-like mixture of agar and water. After it is freeze-dried to remove the water, it is left as a honeycomb of dried agar filled with air, with cell sizes two to three micrometers (2-3 µm) in diameter.
SEAgel can have many different uses. Laboratory scientists use SEAgel as targets for x-ray laser experiments because it can be doped with other materials, such as selenium. In order to eliminate the volatile hydrodynamics that occur when a solid-density target explodes before it reaches the density required for lasing, scientists are trying to develop an x-ray laser target with a density that is less than the critical density of laser light (4×1021 electrons/cm3 for 0.53-µm light). SEAgel can help them achieve a more uniform plasma, which will ultimately improve the quality of the x-ray laser beam.
SEAgel could also be used as food packaging or the encapsulating material of timed-release medical pills, as it is safe to digest. SEAgel could also replace balsa wood to insulate supertankers and to provide sound damping in high-speed trains.
SEAgel is covered under U.S. patents 5,382,285[1] ("Biofoam") and 5,360,828[2] ("Biofoam II").
