PhD student at the University of Turku Lauri Marttila in his doctoral research studied materials that can be used for energy storage in power sources of biocompatible and biodegradable devices.
Biocompatible or biodegradable electronic devices could be used, for example, in medical diagnostics or environmental analytics.
“Melanins such as eumelanin are widely found in nature, for example in human skin, hair and eyes. I think they are extremely interesting materials, and we are investigating their suitability for energy storage,” says Marttila in the press release.
Applied research on melanins is being done around the world, but there are still many open questions related to the chemistry of the materials. The structure of melanins is so complex that it is impossible to find out exactly.
However, materials resembling natural eumelanin can be produced in the laboratory. The most studied eumelanin analog is polydopamine, which is produced by oxidizing the neurotransmitter dopamine.
The aim of the dissertation research was to learn to understand melanin materials better by studying the effect of pH and metal ions on the formation of polydopamine.
Multi-layer films with an advanced method
Marttila learned about the production of multilayer films and their use in the production of functional thin films. He investigated whether oxidizing films can be used to produce energy-storing films.
“Chemically oxidizing membranes are simply membranes with an oxidant bound to them, such as cerium(IV) ions. With the help of oxidizing films, functional films can be produced by simply immersing them in a suitable starting material solution,” says Marttila.
Oxidizing multilayer films have been developed at the University of Turku. Thanks to Marttila’s research, their working principle is now known more precisely.
“Oxidable multilayer films have long been produced using the traditional dip-layer growing method, where the desired surface is alternately immersed in suitable starting material solutions with intermediate rinses.”
“In my dissertation work, however, we produced oxidizable multilayer films using a more advanced spray-spinning-layer growth method, and thus improved the quality of the films and shortened their deposition time,” says Marttila.
The first of the investigated functional films was based on a biocompatible pedot conducting polymer. The ability of the thin film to store energy was promising.
“Furthermore, we oxidized the eumelanin analog DHI melanin into the oxidizing multilayer films. Melanin films are promising components for biodegradable supercapacitors, and in the research we gained new information about these very interesting materials.”
“All in all, the work is a good step as part of wider materials research,” sums up Marttila.