Electrically Conductive Nanocarbon/Elastomer Composite Inks for Flexible and Wearable Strain Sensing

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Electronics

Background:

• Flexible strain sensors are crucial for wearable devices in health monitoring and human-machine interaction.
• Developing sustainable and high-performance conductive materials is essential for advancing wearable technology.

Purpose of the Study:

• To create an eco-friendly, all-carbon conductive ink for flexible strain sensors.
• To demonstrate the sensor's capability in various applications, including motion tracking and health monitoring.

Main Methods:

• Formulation of an all-carbon conductive ink using carbon nano-onions (CNOs) and carbon nanotubes (CNTs) in a biodegradable elastomeric matrix with biomass-derived solvent.
• Fabrication of compressive strain sensors via dip coating polyurethane sponges.
• Fabrication of tensile strain sensors via blade coating on stretchable textiles.

Main Results:

• Compressive sensors exhibited a modulus of ≈460 kPa and gauge factor of ≈1.1.
• Tensile sensors achieved gauge factors of 10-12 at 0.6% strain and high cycling stability (>7000 cycles).
• Sensors successfully detected football dynamics and monitored human breathing in real-time.

Conclusions:

• The developed carbon-based ink provides a scalable, solvent-safe route for sustainable flexible electronics.
• The optimized ink rheology and conductive network morphology lead to high-performance strain sensors.
• The study highlights the potential of CNOs and CNTs in advanced wearable sensor applications.