Multi-functional "superfoam" soaks up oil spills and kills bacteria
Scientists at the University of Georgia have created a "superfoam" with two very valuable potential applications. It could be used not only to clean up oil spills, but also to keep infections from occurring at medical implant sites.
Developed by a team led by Assoc. Prof. Hitesh Handa, the three-dimensional material consists of a PDMS (polydimethylsiloxane) matrix which is augmented with graphene nanoplatelets and antibacterial copper microparticles. These additions give the foam a coarse, porous structure which is both hydrophobic (water-repelling) and oleophilic (oil-attracting).
When sponges made of the foam were placed in water polluted with oil, they adsorbed the oil while not taking in any of the water. Once that adsorbed oil had been removed from the foam, the sponges could be reused multiple times to take up more oil.
Along with oil, the sponges were also found to take in other non-polar water-polluting liquids such as chloroform, hydrochloric acid and other organic pollutants – leaving the water itself behind. And thanks to the presence of the copper microparticles, any bacteria making contact with the foam were killed.
With that functionality in mind, the scientists also envision thin layers of the material being applied to the surface of medical implants. The foam could then minimize the chances of infection by not only killing bacteria, but also repelling fluids such as blood.
"Current medical devices are prone to contamination," said Handa. "When you put any medical device into the body, proteins are the first thing to stick to a surface, and they act like a glue that allows blood or bacteria to adhere. So, if we can stop the protein adsorption, half the battle is won."
Finally, as an added bonus, the graphene nanoplatelets in the foam make it electrically conductive, boosting its potential uses.
The research is described in a paper that was recently published in the journal ACS Applied Materials & Interfaces.