Plastic components are essential in infrastructure and transportation, from water pipes to airplanes. However, they degrade over time due to mechanical stress, leading to costly replacements to ensure safety.

Xiaoran Hu, assistant professor of chemistry and member of the BioInspired Institute, is addressing this issue with groundbreaking research supported by the University and the American Chemical Society (ACS) Petroleum Research Fund. His team has developed highly sensitive mechanophores molecules that change properties when stressed. These configurational mechanophores undergo mechanochemical isomerization, allowing materials to change color when subjected to mechanical force. This innovation could revolutionize self-monitoring plastics, providing real-time stress detection in critical applications like transportation and infrastructure.

These new molecules could enable research into previously unobservable mechanical events in different materials, including synthetic plastics and biomaterials, Hu says.

The newly developed mechanophores respond to forces as low as 131 piconewtons significantly lower than any known mechanochemical reaction. To put this into perspective, traditional reactions that break carbon-carbon bonds require nanonewton level forces, while biological processes like DNA unzipping or protein unfolding occur within the 150-300 pN range. The extreme sensitivity of Hu’s mechanophores makes them invaluable for studying nanoscale mechanical stress in both engineered and biological systems.

Unlike conventional mechanophores that degrade under heat or light, these new molecules remain stable in diverse environments. Their application extends beyond self-reporting plastics to mechanobiology, where they could help researchers understand how mechanical forces regulate biological functions.

Hu’s research paves the way for the next generation of mechano-responsive materials, with potential uses in structural health monitoring, advanced materials science, and cellular mechanics. His team is now working on further enhancing these sensors with fluorescence and other functional responses, exploring their integration into mechanosensitive elastomers and coatings for safer, smarter materials.

We aim to apply our mechanophores to different material platforms and explore their potential for investigating cellular processes in the future, Hu says.

Source: https://news.syr.edu/blog/2025/03/27/as-chemist-develops-ultrasensitive-molecular-force-sensors/