By Rebecca Morelle and Liz Seward
BBC News, York
Gum splattered streets could soon be no more thanks to a virtually non-stick chewing gum that has been invented by UK scientists.
Discarded gum is a major headache for street cleaners
If it passes European health and safety tests, it could be in our shops by next year, the chemical company developing the gum says.
Revolymer claims its product is easier to remove from pavements, shoes and carpets than gums currently on sale.
Its research was presented at the BA Festival of Science, in York.
Chewing gum clean-up costs can be extremely high.
London's Westminster Council recently released figures showing that it had spent more than £100,000 a year to remove chewing gum from its streets; in Oxford the total was £45,000.
For years, scientists have been working on ways to solve the problem.
Now Revolymer, a Bristol University spin-out company, claims that it has created a new material which can be added to gum that makes it much easier to remove from surfaces.
The material is formed from long chains of molecules, called polymers, which have both water-loving (hydrophilic) and water-hating (hydrophobic), and therefore oil-loving, properties.
The polymer's affinity for oil means that it can be easily mixed into the rest of the ingredients needed to create chewing gum; but it is its attraction to water that gives it its non-stick abilities.
Chief Scientific Officer of Revolymer, Professor Terence Cosgrove, said: "The hydrophilic coating means that you always get a film of water around the gum and that is one of the reasons it is easy to remove - and, in some cases, doesn't stick at all."
Degrades in water
The researchers have been testing the gum - a working name is Rev7 - on a number of surfaces.
Recent tests on four different types of paving stones showed that the gum vanished from the surfaces within 24 hours - possibly removed by rain from the UK's very wet summer or street cleaning - while other gums remained stuck for several days.
For some types of shoe, the gum could be pulled straight off immediately; other shoe types needed water to wash it off; while leather soles needed water and a detergent to detach the gum. Commercial gums remained stuck fast.
The new gum is said to degrade much faster
Preliminary results suggested the gum with added polymer eventually dissolves in water.
Professor Cosgrove said: "If a piece of chewing gum has been washed off and has gone down a sewer somewhere, obviously you want it to degrade."
The team also tested the gum on one of the most tricky surfaces - hair. Using the company CEO's daughter - who said she was due a haircut - as a volunteer, they attached commercial gum to one side of her hair and Rev7 to the other.
The commercial gum eventually had to be cut out, but Rev7 could be mostly removed using water, shampoo and a comb.
Professor Cosgrove admitted that getting it out was still a difficult task.
The scientist said 20 people had tasted the gum and said it was comparable to commercial gum in terms of taste and texture.
The company now needs to get its polymer accepted as a food product by passing EU health and safety tests. It can then go on sale.
Professor Cosgrove says he is hopeful that the gum will pass them, and says the product could be on the market as early as next year, either as a Revolymer product or through a partnership with one of the major chewing gum manufacturers.
Scientists at the University College Cork, Ireland, recently announced they were creating a biodegradable gum; while a Queen's University team is taking a different tack by developing a super-solvent that would remove even the stickiest of gums.