Skip to main content

Synopsis: Liquid to Liquid

Synopsis Image
R. Shimizu et al., Phys. Rev. Lett. (2014)
The most familiar phase transitions of water are when it freezes into a solid or evaporates into a gas. But water, like a small handful of other liquids, can also exist in multiple liquid states, which are distinguished by their density and the local order of the molecules. Such liquid-liquid phase transitions are rare, and finding new ones would allow scientists to probe the fundamental nature of the liquid state. Writing in Physical Review Letters, Hajime Tanaka, and co-workers from the University of Tokyo, Japan, present optics experiments showing that triphenyl phosphate (TPP)—a material commonly used as a flame retardant—exhibits a liquid-liquid phase transition.
Researchers have previously shown that supercooling TPP (that is, quickly cooling it to a temperature below which it would normally freeze) leads to density changes that could be signs of a liquid-liquid phase transition. But small nanocrystals were also observed to form upon supercooling TPP, suggesting that instead of undergoing a liquid-liquid phase transition, TPP might actually be freezing, albeit very slowly.
To separate the two phenomena, Tanaka and co-workers supercooled TPP to various temperatures below its freezing point and used polarized and depolarized light to measure the liquid’s refractive index (which is sensitive to the liquid density) and optical anisotropy fluctuations (which track the formation of nanocrystals) over time. The researchers saw evidence for both density changes and nanocrystal formation upon cooling. But their key finding was a temperature at which isotropic density fluctuations first increased and then decreased over time—a possibility that can’t arise from crystal formation and therefore likely arises from a true liquid-liquid transition. The results suggest that while crystallization and the liquid-liquid phase transition occur simultaneously, they are in fact different phenomena. – Katherine Wright

Comments

Post a Comment

Popular posts from this blog

Einstein’s Lost Theory Describes a Universe Without a Big Bang

Einstein with Edwin Hubble, in 1931, at the Mount Wilson Observatory in California, looking through the lens of the 100-inch telescope through which Hubble discovered the expansion of the universe in 1929.  Courtesy of the Archives, Calif Inst of Technology. In 1917, a year after Albert Einstein’s  general theory of relativity  was published—but still two years before he would become the international celebrity we know—Einstein chose to tackle the  entire universe . For anyone else, this might seem an exceedingly ambitious task—but this was Einstein. Einstein began by applying his  field equations of gravitation  to what he considered to be the entire universe. The field equations were the mathematical essence of his general theory of relativity, which extended Newton’s theory of gravity  to realms where speeds approach that of light and masses are very large. But his math was better than he wanted to believe—...
Post a Comment
Read more

There’s a Previously Undiscovered Organ in Your Body, And It Could Explain How Cancer Spreads

Ever heard of the interstitium? No? That’s OK, you’re not alone  —  scientists hadn’t either. Until recently. And, hey, guess what  —  you’ve got one! The interstitium is your newest organ. Scientists identified it for the first time because they are better able to observe living tissues at a microscopic scale, according to a recent study published  in  Scientific Reports , Scientists had long believed that connective tissue surrounding our organs was a thick, compact layer. That’s what they saw when they looked at it in the lab, outside the body, at least. But in a routine endoscopy (exploration of the gastrointestinal tract), a micro camera revealed something unexpected: When observed in a living body, the connective tissue turned out to be “an open, fluid-filled space supported by a lattice made of thick collagen bundles,” pathologist and study author Neil Theise  told  Research Gate . This network of channels is present throughout ...
Post a Comment
Read more

First light-bending calculator designed with metamaterials

Exotic materials that bend light in extreme ways could be used to perform complex mathematical operations, creating a new kind of analogue computer. Tools for manipulating light waves have taken off in recent years thanks to the development of  metamaterials . These materials have complex internal structures on scales smaller than the wavelength of the light they interact with, and so they produce unusual effects. Most famously, metamaterials promise to deliver " invisibility cloaks " that can route light around an object, making it seem to disappear. Nader Engheta  at the University of Pennsylvania, Philadelphia, and his colleagues decided to explore a different use for metamaterials, one that adapts the  old idea of analogue computing . Today's digital computers are based on electrical switches that are either on or off. But before these machines were analogue computers based on varying electrical or mechanical properties. The  slide rule  is one example...
Post a Comment
Read more