Self-healing organic semiconductors for bionic skin

Material degradation is a primary concern to every material scientist and engineer, not only does degradation lead to failure, but results in the need for repair - a very costly endeavour. In this perspective, it is of interest to develop self-healing materials that will make maintenance redundant. As opposed to inorganic semiconductors, organic semiconducting materials are soft, which makes them ideal to be used in flexible and stretchable electronic devices, which can be directly applied to the human skin. Wearable electronics, however, are particularly prone to mechanical damage and fatigue, which is why it is paramount to develop more robust materials, like self-healable semiconductors.

This fellowship will, for the first time, make it possible to synthesise intrinsic self-healing organic semiconductors and incorporate them into fully flexible, stretchable and wearable electronic devices, respectively bionic skin, to measure biological metabolites associated with diabetes (glucose), fatigue (lactate) and stress (cortisol). The electric charges will be transported via the conjugated polymer backbone, while additional supramolecular functionalities (i.e. non-binding interactions) will be incorporated into the chemical structure to ensure self-healing via the formation of dynamic bonds. The study of the new self-healing polymers will then be extended to other dynamically bonding functional groups to evaluate which chemistry is best suited for organic semiconductors. Subsequent steps will focus on the self-healing dynamics and rates, and the incorporation of the new materials into flexible electronic prototype devices.

The realisation of healable organic semiconductors, for the first time, will allow the fabrication of lightweight, -wearable sensors directly applied to the human skin. This will make it possible to continuously monitor medically relevant body functions and present a significant step forward in the development of affordable biological sensors and continuous patient monitoring, ultimately enhancing medical diagnostics and opening-up new treatment possibilities.

Electronic skin could be the ultimate medical sensor of the future, if we were able to manufacture a robust soft material, able to transmit electrical signals, we could wear sensors directly under our cloth on our skin to monitor vital body functions or biological metabolites associate with common medical conditions such as diabetes (glucose), fatigue (lactate) or stress (cortisol). This fellowship will pave the way towards such materials, by making the development of self-healing organic semiconductors possible. Skin-integrated electronics are non-evasive, allow direct contact with the skin for analyte uptake and significantly improve patient well-being due to enhanced comfort and wearability, and it comes to no surprise that current market analysis predicts compounded annual growth rates in excess of 30% by 2025, reaching an overall market value of $1.7 billion. HM Treasury and the Department for Business, Innovation & Skills identified wearable electronics as one of "the eight great technologies" with high market potential and long-term benefits for society in 2010. The potential for impact, however, goes far beyond the economic benefits. The proposed fellowship will have a profound impact on the development of wearable electronic devices and presents a significant step forward in the development of cheap biological sensors and bio-inspired robotics that ultimately could open-up new medical diagnostics and treatments. The research outlined in this proposal will boost the UK's capabilities in various strategically relevant scientific and technological domains and will benefit both basic and applied science. With DuPont Teijin Films, the project is supported by one of the world's leading innovators in polyester films for flexible electronic applications and highlights the value of the proposed research to the UK manufacturing industry. It is noteworthy that self-healing organic semiconductors are not limited to one specific application and have the potential to disrupt a breadth of application areas such as lightweight organic light emitting diode (OLED) and textile integrated organic photovoltaics (OPV). Lastly, the human impact of the project should not be underestimated. Besides the two postdoctoral researchers involved in the project, UCL generously agreed to fund a three-year PhD studentship. Due to the interdisciplinary nature of the project and the strong links to the industrial partner, the three scientists involved in the project will benefit not only from the excellent research and training facilities at UCL but also from the industrial expertise. By acquiring a large set of skills and gaining expertise in academic and industrial research environments, the PDRA/PhD students significantly improve their employment opportunities after the conclusion of this project, respectively the corresponding PhD programs.