A soap film with one side chemically different from the other could be used for artificial photosynthesis in the future.
鈥淎ll other soap films and bubbles made in the history of mankind have been the same [on both sides]. We are making the first ones that are not the same,鈥� says at Uppsala University in Sweden.
Hammarstr枚m and his colleagues created these films in an effort to design a soap-based device for photosynthesis, the chemical reaction used by plants to convert sunlight into the compounds they need to grow. But calculations and computer simulations of these processes in the soap films showed the researchers that they could only mimic photosynthesis if the two sides of the film were chemically different. If they were identical, the device would experience the equivalent of a battery short-circuiting.
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The sides of a single film don鈥檛 differ naturally, so the team had to modify the chemistry without destroying the fragile film. Methods like pipetting different chemicals on each side were too destructive, but the researchers ultimately found that spraying different molecules on each side of the film did the trick.
In this way, they repeatedly created small samples of soap films that lasted for a few minutes at a time and had two chemically distinct sides. The molecules they sprayed respond to light, which helped the researchers confirm that the two sides of the film were different, and they are an appropriate stand-in for the light-sensitive molecules required for photosynthesis. In nature, plants and bacteria use energy from sunlight to chemically process water and carbon dioxide into sugar that can fuel their growth. The soap film would similarly host chemical reactions with water on one of its sides and carbon dioxide on the other in order to produce useful chemicals like novel fuels.
The films do not enable photosynthesis yet but, together with a prototype of a device that can keep producing many films one after another, the new experiment is a key step towards it.
鈥淲e now have all the pieces, and they are working independently. Next, we have to integrate them into one device,鈥� says team member at Leiden University in the Netherlands. Soap is also much less costly and takes less energy to make than artificial photosynthesis devices that use more solid components, says at Wasabi Innovations in Bulgaria, who worked on the project.
Soap films like these do make for a good imitation of membranes and molecules that are important for photosynthesis in nature, says at the University of Bordeaux in France. 鈥淚f you want to be inspired by nature, which does [photosynthesis] very, very well, this may be a good way,鈥� he says.
Journal reference:
Physical Review Letters,
