Glasgow Team Creates Self-Sensing Auxetic Plastics via 3D Printing

Glasgow Team Creates Self-Sensing Auxetic Plastics via 3D Printing

(IN BRIEF) An international team led by the University of Glasgow has developed 3D-printed auxetic lattices from PEEK infused with carbon nanotubes that broaden under tension and autonomously sense strain through piezoresistivity. Detailed in Materials Horizons, the study couples finely tuned double-Y geometries with a predictive computational model, enabling programmable combinations of strength, flexibility, and real-time damage detection without embedded electronics. Building on earlier PLA-based work, these durable, load-bearing materials promise applications in smart implants, aerospace components, and wearable health monitors, propelled by custom design software and supported by funding from Indian, US, and UK research councils.

(PRESS RELEASE) GLASGOW, 15-Jul-2025 — /EuropaWire/ — Researchers at the University of Glasgow, in collaboration with international partners, have unveiled a pioneering class of 3D-printed “smart” plastics that combine unusual deformation behaviour with self-monitoring capabilities. Published in Materials Horizons, the breakthrough demonstrates how additive manufacturing of auxetic architectures in high-performance engineering plastics can yield materials that not only widen when stretched but also detect their own strain and damage in real time—without embedded electronics.

Auxetic materials invert the usual response to tension: instead of thinning, they expand laterally, granting superior energy absorption and damage tolerance. The team harnessed these properties in polyetheretherketone (PEEK), a robust, lightweight, and biocompatible polymer widely used in both industrial and medical settings. By producing intricately patterned lattices infused with carbon nanotubes, the researchers imparted electrical conductivity to the plastic. As the lattice deforms under load, its electrical resistance shifts—a piezoresistive effect that serves as an intrinsic sensor of mechanical stress.

“Our work shows that 3D-printed PEEK lattices can be programmed to exhibit specific levels of auxeticity, stiffness, and sensitivity,” explained Professor Shanmugam Kumar of the James Watt School of Engineering. “This opens the door to smart orthopaedic implants, adaptive aerospace skins, and wearable devices that continuously monitor their structural health.”

Each design employs a repeating double-Y motif—branch-stem-branch units whose geometry (thickness, angle, spacing) can be tuned to create a spectrum of mechanical and sensing performance. Accompanying the experimental effort, the team developed a computational model that reliably predicts how both mechanical deformation and electrical resistance evolve under different loading scenarios, enabling virtual optimization before printing physical prototypes.

This study builds on the group’s earlier work with PLA-based auxetic lattices, which leveraged biodegradable polymers infused with carbon black to create 56 sensor-enabled geometries for low-load or disposable applications. The new PEEK-based structures, by contrast, target demanding, permanent uses. Both efforts are underpinned by bespoke software tools that streamline the exploration of architected material design spaces, accelerating innovation.

Funded by India’s Department of Science and Technology, the US National Science Foundation, and the UK’s EPSRC, and undertaken with colleagues at the Polytechnic University of Marche and Texas A&M University, this research offers a blueprint for the next generation of multifunctional, self-sensing materials across medicine, transportation, and structural monitoring.

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SOURCE: University of Glasgow