page_title: Polyethylene glycol
section_title: Chemical uses
hierarchical_section_title: Polyethylene glycol / Uses / Chemical uses
caption_attribution_description: Terra Cotta Warriors: Guardians of China's First Emperor Location: National Geographic Museum Date: Nov. 19, 2009 – March 31, 2010 Website: www.warriorsdc.org Overview: "Terra Cotta Warriors: Guardians of China's First Emperor" features the largest number of terra cotta figures ever to travel to the United States for a single exhibition. The exhibition showcases 15 terra cotta figures from the tomb of China’s First Emperor, Qin Shihuangdi, who ruled from 221 B.C to 210 B.C., including nine terra cotta warriors, two musicians, a strongman, a court official, a stable attendant and a horse. The exhibition features 100 sets of artifacts in all, including weapons, stone armor, coins, jade ornaments, roof tiles and decorative bricks, and a bronze crane and swan.
context_page_description: Polyethylene glycol is a polyether compound with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide or polyoxyethylene, depending on its molecular weight. The structure of PEG is commonly expressed as H−ₙ−OH.
context_section_description: Because PEG is a hydrophilic molecule, it has been used to passivate microscope glass slides for avoiding non-specific sticking of proteins in single-molecule fluorescence studies.
  Polyethylene glycol has a low toxicity and is used in a variety of products. The polymer is used as a lubricating coating for various surfaces in aqueous and non-aqueous environments.
  Since PEG is a flexible, water-soluble polymer, it can be used to create very high osmotic pressures (on the order of tens of atmospheres). It also is unlikely to have specific interactions with biological chemicals. These properties make PEG one of the most useful molecules for applying osmotic pressure in biochemistry and biomembranes experiments, in particular when using the osmotic stress technique.
  Polyethylene glycol is also commonly used as a polar stationary phase for gas chromatography, as well as a heat transfer fluid in electronic testers.
  PEG has also been used to preserve objects that have been salvaged from underwater, as was the case with the warship Vasa in Stockholm, and similar cases. It replaces water in wooden objects, making the wood dimensionally stable and preventing warping or shrinking of the wood when it dries. In addition, PEG is used when working with green wood as a stabilizer, and to prevent shrinkage.
  PEG has been used to preserve the painted colors on Terracotta Warriors unearthed at a UNESCO World Heritage site in China. These painted artifacts were created during the Qin Shi Huang dynasty (first emperor of China). Within 15 seconds of the terra-cotta pieces being unearthed during excavations, the lacquer beneath the paint begins to curl after being exposed to the dry Xi'an air. The paint would subsequently flake off in about four minutes. The German Bavarian State Conservation Office developed a PEG preservative that when immediately applied to unearthed artifacts has aided in preserving the colors painted on the pieces of clay soldiers.
  PEG is often used (as an internal calibration compound) in mass spectrometry experiments, with its characteristic fragmentation pattern allowing accurate and reproducible tuning.
  PEG derivatives, such as narrow range ethoxylates, are used as surfactants.
  PEG has been used as the hydrophilic block of amphiphilic block copolymers used to create some polymersomes.
  PEG has also been used as a propellent on the UGM-133M Trident II Missile, in service with the United States Air Force.
caption: Terra cotta warrior, showing traces of original color
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