Self-Restoring Capacitive Pressure Sensor Based on Three-Dimensional Porous Structure and Shape Memory Polymer.

Area of Science:

• Materials Science
• Polymer Science
• Sensor Technology

Background:

• Polyurethane (PU) porous structures are used in flexible capacitive pressure sensors due to their elasticity.
• However, PU-based sensors lack durability during repeated pressure application, limiting practical use.
• Enhancing the durability of flexible pressure sensors is crucial for widespread adoption.

Purpose of the Study:

• To develop a flexible pressure sensor with enhanced durability using a shape memory polymer (SMP).
• To investigate the performance of an SMP-based porous structure in capacitive pressure sensing applications.
• To demonstrate the potential of the developed sensor for real-time pressure monitoring.

Main Methods:

• Fabrication of a 3D porous SMP structure using a sugar templating process and capillary action.
• Integration of the SMP porous structure into a capacitive pressure sensor.
• Evaluation of sensor performance, including durability under cyclic pressure, sensitivity, stability, response time, and hysteresis.
• Testing the sensor for real-time shoe insole pressure detection.

Main Results:

• The SMP porous structure demonstrated notable durability, maintaining sensing performance for 100 cycles at 500 kPa.
• The SMP material exhibited rapid shape recovery (within 30 s at 80 °C).
• The SMP-based sensor showed higher sensitivity (0.0223 kPa⁻¹) and excellent stability, response time, and hysteresis compared to PU sensors.
• The sensor successfully detected real-time shoe insole pressures, showcasing durability and motion differentiation.

Conclusions:

• Shape memory polymers significantly enhance the durability of flexible porous pressure sensors.
• The developed SMP-based sensor offers superior performance characteristics for pressure sensing applications.
• This technology holds promise for advanced applications like wearable health monitoring and smart insoles.