Iono-Elastomer-Based Wearable Strain Sensor with Real-Time Thermomechanical Dual Response

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Developing advanced materials for wearable sensors requires high stretchability and sensitivity to multiple stimuli.
• Existing materials often compromise on performance when integrating thermomechanical sensing capabilities.

Purpose of the Study:

• To create an ultrastretchable iono-elastomer with simultaneous sensitivity to elongation strain and temperature.
• To investigate the structure-property relationships governing the material's unique responses.

Main Methods:

• Hierarchical self-assembly of end-functionalized triblock copolymer in ethylammonium nitrate.
• Cross-linking of the self-assembled structure.
• In situ small-angle X-ray scattering (SAXS) during uniaxial elongation.
• Characterization of mechanical properties, ionic conductivity, and thermomechanical sensing performance.

Main Results:

• The iono-elastomer achieved 340% stretchability with highly linear resistance-strain response (R² = 0.998).
• A large temperature gauge factor (3.24%/°C at 30 °C) was observed.
• In situ SAXS revealed a nanoscale microstructural transition, including micelle elongation and face-centered-cubic ordering, correlating with mechanical and conductivity changes.
• The material demonstrated good cyclability and resistance to physical damage.

Conclusions:

• The developed iono-elastomer offers an unprecedented combination of high stretchability, linear strain sensing, and temperature sensing.
• The hierarchical self-assembly and in situ microstructural transitions are key to the material's superior thermomechanical sensing capabilities.
• This material shows significant potential for advanced wearable sensors capable of simultaneously monitoring motion and temperature.