All-Polydimethylsiloxane-Based Highly Flexible and Stable Capacitive Pressure Sensors with Engineered Interfaces for...

Area of Science:

• Materials Science
• Sensor Technology
• Biomedical Engineering

Background:

• Flexible pressure sensors are crucial for electronic skin applications requiring static and dynamic pressure sensing.
• High flexibility, sensitivity, low hysteresis, and stability are essential for conformable pressure mapping and rugged electronic skin structures.

Purpose of the Study:

• To develop a novel, highly flexible capacitive pressure sensor with engineered stable interfaces.
• To achieve a wide pressure sensing range, high sensitivity, low hysteresis, and superior stability for electronic skin applications.

Main Methods:

• Fabrication of a capacitive pressure sensor using PDMS-based substrates, a micropyramidal dielectric layer, Au electrodes, and MPTMS molecular adhesive.
• Engineering five stable interfaces within the sensor/matrix stack using molecular adhesion and PDMS lamination.
• Development of a 4x4 flexible pressure sensor matrix capable of conforming to various surfaces.

Main Results:

• A highly flexible sensor with a wide pressure range (up to 550 kPa), high sensitivity (46.6 MPa⁻¹ at ≤1 kPa), low hysteresis (4.05%), and high stability (11,400 cycles at 250 kPa).
• Demonstration of arterial pulse signal acquisition and press task performance.
• Successful implementation of a 4x4 sensor matrix for single-point and multipoint pressure sensing on planar and non-planar surfaces, showing a maximum shear strain of 2.27 N.
• Comparative analysis highlighting the superior flexibility and stability over semi-flexible sensors.

Conclusions:

• The developed process is simple, scalable, and yields a conformably stable pressure sensor matrix suitable for advanced electronic skin development.
• The novel sensor design overcomes limitations of existing technologies, offering significant advantages in flexibility and durability for wearable electronics.