Highly Stretchable and Sensitive Pressure Sensor Array Based on Icicle-Shaped Liquid Metal Film Electrodes

Area of Science:

• Materials Science
• Electrical Engineering
• Wearable Technology

Background:

• Flexible pressure sensors are crucial for wearable electronics, demanding high sensitivity and stretchability.
• Simultaneously optimizing electrical performance and mechanical stretchability remains a significant challenge in sensor design.

Purpose of the Study:

• To develop a straightforward, cost-effective method for fabricating highly stretchable and sensitive capacitive pressure sensor arrays.
• To address the challenge of maximizing both electrical performance and mechanical stretchability in flexible pressure sensors.

Main Methods:

• Fabrication of capacitive pressure sensors using an icicle-shaped liquid metal film electrode integrated with an elastomer.
• Utilizing a unique elastic bump structure that increases electrode overlap and decreases separation distance under pressure.
• Designing and processing liquid metal and elastomer for reliable sensor performance.

Main Results:

• Achieved high sensitivity of 39% kPa⁻¹ within the 0-1 kPa range.
• Demonstrated a low limit of detection as low as 12 Pa.
• Exhibited excellent stretchability up to 94% strain without failure and a hysteresis error of 8.46% at 25 kPa.

Conclusions:

• The developed sensor offers a novel capacitive sensing scheme with enhanced sensitivity and superior mechanical properties.
• Successfully demonstrated applications in force measurements on curved surfaces, contour mapping, and monitoring cervical postures.
• This cost-effective fabrication method provides a promising solution for advanced wearable electronic applications.