3D Printable Elastic Polymer Combines Toughness With Fatigue Resistance
Researchers at the Swiss Federal Institute of Technology Lausanne (EPFL) have developed a 3D printable elastic material that combines high fracture toughness with resistance to repeated mechanical stress. The innovation could support longer-lasting components for soft robotics, wearable electronics and biomedical devices.
A Dual-Network Material
The material, known as a double network granular elastomer (DNGE), was first introduced by EPFL’s Soft Materials Laboratory in 2024. It consists of microscopic, relatively stiff elastomer particles connected by a second, softer elastomer network.
DNGEs were originally developed as printable ‘inks’ for manufacturing flexible structures with precisely controlled mechanical properties. Follow-up research, published in Science Advances, now shows that the same granular architecture also makes the elastomers unusually tough and durable.
Conventional elastomers often involve a trade-off between fracture toughness and fatigue resistance. Materials that can withstand sudden stretching or impact may gradually accumulate damage under repeated stress. Conversely, fatigue-resistant elastomers can remain vulnerable to tearing or fracture when subjected to extreme deformation.
Stress Redistribution Limits Damage
In tests, optimised DNGEs achieved fracture-toughness values up to 15 times higher than those of comparable elastomers. Their fatigue resistance was up to three times higher.
This performance results from the way the two interlinked networks distribute mechanical strain. When the material is stretched, stress moves from the stiffer microparticles into the softer regions between them. Polymer chains in these areas can slide and rearrange, dissipating energy repeatedly without permanently breaking chemical bonds.
The granular structure also influences crack propagation. Instead of travelling directly through the material, cracks follow a winding route through the softer areas between the particles. This slows their growth and delays structural failure.
Towards More Sustainable Elastomers
The combination of mechanical durability and 3D printability could offer product, automotive and fashion designers greater freedom to create flexible components with tailored performance. Potential applications include soft robotic parts, flexible electronics, responsive wearables and medical devices that must withstand frequent bending, compression or stretching.
Longer service life could reduce replacement frequency and associated material consumption. However, the researchers are also investigating ways to lower the material’s environmental impact more directly. Future versions may incorporate biodegradable elastomers or polymers derived from recycled feedstocks without sacrificing mechanical performance.
Because DNGEs can be processed using commercially available 3D printers, the material architecture may also make advanced elastomer research and small-scale production more accessible.
Source: EPFL
Photos: EPFL / Titouan Veuillet