Archive for the ‘Chemistry World’ Category

Shape memory polymers get a grip

Researchers in the US have developed a new way to curl polymer sheets to create a variety of 3D structures.

Shape memory polymers change shape in response to external stimuli such as light and heat. Chemists add active materials to polymer sheets, which then deform on stimulation. Usually the active materials are placed in regions where curvature is desired, but Michael Dickey, Jan Genzer and their colleagues at North Carolina State University have now shown they can deform regions adjacent to the active materials.

 

Source: © Royal Society of Chemistry



Read the full story by Laura Fisher in Chemistry World.


This article is free to access until 14 April 2017.

A M Hubbard et al, Soft Matter, 2017, DOI: 10.1039/c7sm00088j

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Cracking theory helps understand paint ageing

New model could benefit art conservators and geologists

Source: © Royal Society of Chemistry / Image courtesy of Mauritshuis Museum.

Understanding how cracking patterns develop in desiccated surfaces like old oil paintings or dried mud is surprisingly difficult. Now a Chilean scientist has established the first mathematical model of cracked surfaces that could help conservators preserve old paintings or give geologists information about the thickness of cracked clay or salt layers, and the stress they’ve been subjected to.

In oil paintings, the varnish becomes less flexible with age and when the canvas shrinks and expands in response to humidity and temperature changes, the paint starts to crack. As the cracks are hard to forge, art experts often use them, among other factors, to determine a painting’s authenticity. ‘Crack networks are like fingerprints,’ says JC Flores from the University of Tarapacá, who has developed a series of equations that give a theoretical insight into cracking patterns.

Read the full story by Kat Kramer in Chemistry World.


This article is free to access until 10 March 2017.

J C Flores, Soft Matter, 2017, DOI: 10.1039/c6sm02849g

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How to not make a splash

Study adds to understanding of droplet behaviour

New research by a scientist in the US can better explain how a droplet splash is dictated by the smoothness of a surface, as well as the surrounding air pressure.

Source: © Royal Society of Chemistry


Scientists already knew that two aspects were involved in this seemingly simple process; one related to the surrounding air, and the other to how the liquid spreads on the substrate. ‘If we were forced to guess, we’d probably assume that decreasing the ambient pressure around the drop would make the splash bigger. After all, we’re decreasing air resistance,’ explains Andrzej Latka, at the University of Chicago, who performed the new research.

Read the full story and watch the video showing the splash in Chemistry World.



This article is free to access until 28 February 2017.

Andrzej Latka, Soft Matter, 2017. DOI: 10.1039/C6SM02321E

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