A Monolithic Strain-Proximity-Pressure Trimodal Flexible Sensor for Healthcare Monitoring and Wearable Perception

Area of Science:

• Materials Science
• Biomedical Engineering
• Robotics

Background:

• Flexible electronic skins are crucial for personalized healthcare and human-machine interfaces.
• Integrating multiple sensing modalities (strain, proximity, pressure) into one device is challenging due to complexity and performance compromises.

Purpose of the Study:

• To develop a compact, all-in-one trimodal sensor for electronic skin applications.
• To overcome the limitations of structural redundancy and performance trade-offs in multifunctional sensors.

Main Methods:

• An electrode-multiplexed architecture utilizing serpentine conductive traces for dual piezoresistive and capacitive sensing.
• Complementary stacking of electrodes to enhance proximity detection range.
• Integration of a hierarchical iontronic interface to manage pressure sensing sensitivity and range.

Main Results:

• Achieved high strain sensitivity (gauge factor of 3.69) and long-range proximity detection (0-100 mm).
• Demonstrated effective pressure sensing with a dual-sensitivity range (3.75 kPa⁻¹ at 0-60 kPa, 0.99 kPa⁻¹ at 60-200 kPa).
• Successfully monitored physiological signals (pulse, muscle dynamics, respiration) and distinguished material properties.

Conclusions:

• The developed trimodal sensor offers a robust solution for versatile multimodal sensing.
• This technology facilitates advanced applications in human-machine interaction and environmental monitoring.
• Enables physics-informed wearable perception by combining tactile and proprioceptive feedback.