Moscow Polytechnic University, in cooperation with the N.D. Zelinskii Institute of Organic Chemistry of the Russian Academy of Sciences, is developing self-healing polyurethanes for flexible sensors. The materials are produced from furfural, renewable plant raw materials, and can restore their structure after damage such as microcracks and scratches when heated, without human intervention. The research is supported by Moscow Polytech within the grant program named after P.L. Kapitsa under the federal "Priority 2030" program.
The technology is based on the thermoreversible Diels–Alder reaction between furan and maleimide. The key innovation developed by Moscow Polytech researchers is the use of pre-formed functional adducts (7-oxanorbornenes with hydroxyl groups) as direct monomers for polyurethane synthesis. This "monomer-based approach" makes it possible to precisely control cross-link density, network architecture, and the distribution of dynamic bonds.
When heated above 120°C, the polymer bonds dissociate through the retro-Diels–Alder reaction, the material becomes fluid. As it cools, the bonds reform, allowing the polymer to "tighten" microcracks. In contrast to idealized schemes, with multiple reduction cycles, partial deterioration of properties is possible because of unwanted maleimide homopolymerization occurring within the same temperature range. The research team is addressing this current limitation by modifying the structure of the maleimide fragments and introducing additional dynamic bonds, such as hydrogen bonds.
The project is led by Konstantin Galkin, a University's researcher and a recipient of the Russian Academy of Sciences Medal with Prize for Young Scientists. He is also a principal investigator of three Russian Science Foundation projects focused on the use of renewable raw materials for fine organic chemicals and polymer materials. The results of his research have been published in leading international scientific journals.
"The key advantage of these systems is the ability to tailor polymer properties by modifying the structure of the original furan monomers at the adduct synthesis stage. We develop approaches to functionalizing the furan ring that enable us to produce materials with targeted mechanical and optical properties. In the future, this opens the way to sensors that not only withstand mechanical loads but also signal damage through changes in their fluorescence. However, this research direction is still at the fundamental research stage," said Konstantin Galkin.
The practical value of the development lies in significantly extending the service life of flexible sensors. Such sensors are used in wearable electronics and robotics, wh ere replacing or repairing components is often difficult. Even minor mechanical damage (microcrack, fracture) typically renders an ordinary sensor inoperable. By contrast, a self-healing material can restore its functionality after short-term heating without requiring specialist intervention or component replacement. In the current version of the material, healing requires an external thermal pulse, which is suitable for many devices, while future research aims to reduce the activation temperature.
The university is also implementing a student research project involving students specializing in chemistry and materials science. The project aims to develop a prototype of a temperature-sensing self-healing polyurethane that could serve as the basis for a new generation of flexible sensors.
Photo: https://www.magnific.com/ru
