Ecoflex-Passivated Graphene-Yarn Composite for a Highly Conductive and Stretchable Strain Sensor

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Technology

Background:

• Flexible strain sensors are crucial for wearable electronics.
• Improving conductivity and stretchability in composite materials remains a challenge.

Purpose of the Study:

• To develop a highly stretchable and conductive strain sensor using a graphene-yarn composite.
• To compare spray coating with dip coating for fabricating graphene-based sensors.
• To evaluate the sensor's performance and suitability for wearable applications.

Main Methods:

• Fabrication of a graphene-yarn composite via spray coating of graphene nanoplates onto pre-stretched yarn.
• Comparative analysis of spray-coated versus dip-coated sensors.
• Characterization of sensor conductivity, stretchability, and response to strain.
• Passivation of the sensor with an Ecoflex protective layer.

Main Results:

• Spray coating resulted in 3.68 times higher conductivity and 2.1 times higher stretchability than dip coating.
• The spray-coated sensor achieved 310% stretchability with a relative resistance change of 2.27 at 50% strain.
• Passivation with Ecoflex did not degrade sensor performance up to 200% strain.
• The sensor successfully monitored finger movements and wrist pulse.

Conclusions:

• Spray-coated graphene-yarn composites offer superior performance for flexible strain sensors.
• The developed sensor is robust, stretchable, and suitable for real-time wearable monitoring.
• This technology has potential applications in health monitoring and human-machine interfaces.