Gels - mixtures of solid and liquid - are commonplace in everyday life, with a wide range of applications in personal care products, mechanical lubrication, drug delivery systems and biomaterials. And Professor Smith believes that by increasing our understanding of these seemingly mystical materials there may be yet more they can do for us.
“We’ve been fascinated with the characteristics and applications of gel-type materials for some time,” says Professor Smith, who admits his fascination is partly child-like. “Who hasn’t played with jelly - like my five-year-old - and wondered about why it behaves the way it does?
“This is what we are doing in this paper, but by carefully controlling the structures of our gels, and understanding what happens on a molecular level, we can gain a more detailed understanding and can observe new forms of behaviour.”
Professor Smith says his gels contain a “solid-like network assembled within a liquid-like phase holding the whole material together.” Prior to this research it had been assumed the solid-like network was fixed and unable to move, but now Professor Smith and PhD student Jorge Ruiz-Olles have shown this is is not always the case.
“Our gels exchange their ‘solid-like’ components with one another”, he said. “Putting two gels next to each other, and finding that all of the solid parts could slowly diffuse into one another was very surprising to us.” So surprising, in fact, that he describes it as like seeing a brick move into a rock.
“We suspect this kind of behaviour may actually be quite rare in gels”, he says. “In the paper we suggest how other authors may be able to identify whether their gels behave in the same way, so that we can work out just how general this new kind of mobility in gels actually is.”
This behaviour has serious real-world applications: “If the solid-like networks of gels can move this opens up ways in which gels can easily heal or adapt themselves. This opens the longer-term possibilities of developing smart soft materials for use in components that can heal their solid-like networks if they suffer damage.
“Alternatively this general principle could help further develop gels as biomaterials that can effectively adapt and interact their network structures when brought into contact with biological tissue.”
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