Stretchable polymer foam sensors detect a wide range of motion with high sensitivity

A research team led by Professor Wang Long Wang of the Institute for Materials and Technology Engineering (NIMTE) at the Chinese Academy of Sciences has developed a highly stretchable, conductive foam sensor with an ultra-width operating range using supercritical CO2 (SCCO2) foam. This study was published in Tailly Today Physics.

Piezoreos-based distortion sensors utilize conductive elastomer composite foams to detect movement and tactile sensation. These sensors are lightweight, highly compressible, and have a stable response, making them promising for motion tracking, health monitoring, human-robot interaction and robotics applications.

Porous conductive materials are promising for flexible electronic devices. However, electrical failures or material damage during stretching limit the strain response range.

To overcome this challenge, researchers introduced porous structures into separate composites made of high aspect ratio carbon nanostructures (CNS) and flexible polyolefin elastomers (POEs). By using foaming SCCO2, the conductive network structure could be reconstructed, resulting in a porous conductive material with a very large strain response range.

The developed POE/CNS foam exhibits significant elasticity (952.5% strain), elasticity (13.8% residual strain), and electrical conductivity (resistance of 50kΩ). The isolated structure gives the POE/CNS foam sensor an exceptional strain response range of 0.5% to 762%, significantly outperforming the randomly distributed structure.

In addition to high sensitivity, rapid response, and remarkable reproducibility, the POE/CNS foam sensor maintains stable performance over 4,000 tension cycles and exhibits exceptional long-term durability.

This work presents a simple and environmentally friendly way to produce high-performance polymer-based foam sensors, demonstrating the powerful potential of application of wearable electronics and engineering equipment.