Highly Sensitive and Stretchable Strain Sensors Based on Conductive Elastomer Composites

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Flexible strain sensors are vital for surgical robots, wearable electronics, and soft electronic skin.
• Achieving both high sensitivity and large stretchability in strain sensor materials remains a significant challenge.
• Existing highly stretchable polymers often exhibit low gauge factors (GF) due to intact conductive pathways during deformation.

Purpose of the Study:

• To develop novel conductive elastomer composites that overcome the trade-off between sensitivity and stretchability.
• To integrate movable cross-links with carbon-based conductive fillers to enhance strain sensing performance.
• To optimize material composition for superior mechanical and electrical properties.

Main Methods:

• Design and synthesis of four conductive elastomer composite systems.
• Integration of movable cross-links (γ-cyclodextrin) with conductive fillers (Ketjenblack).
• Systematic optimization of molecular weight, γ-cyclodextrin content, and Ketjenblack loading.

Main Results:

• The optimal composition, P1-CD⊃P2/KB (86k, 0.62, 10), demonstrated an ultrahigh gauge factor (GF) of 1500 ± 100.
• Achieved a remarkable fracture strain of 300%, indicating excellent stretchability.
• The composite exhibited excellent durability over 500 stretch-release cycles and enabled precise motion sensing in a robotic hand.

Conclusions:

• Movable cross-linked elastomer composites offer a promising solution for next-generation strain sensors.
• The developed material balances high sensitivity and large stretchability, addressing a key challenge in the field.
• Potential applications include advanced wearable devices and humanoid robotics requiring precise motion detection.