Hierarchically Engineered Interfaces in Flexible Piezoelectric Composite Films for Broad-Range Pressure Sensing.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Flexible piezoelectric sensors face challenges in broad-range pressure sensing due to deformation restrictions and response saturation under high compressive loads.
• Developing robust piezoelectric materials is crucial for applications requiring reliable pressure detection across diverse load conditions.

Purpose of the Study:

• To engineer a flexible piezoelectric composite film with a nacre-inspired hierarchical interfacial architecture for enhanced broad-range pressure sensing.
• To overcome limitations of existing sensors in handling high compressive loads and achieving stable signal output.

Main Methods:

• Fabrication of a flexible piezoelectric composite film using a solvent exchange-induced self-assembly process.
• Incorporation of graphene oxide lamellae at interfaces within a piezoceramic/thermoplastic polyurethane matrix to create a mechanically robust architecture.
• Characterization of the piezoelectric properties (d33, g33) and performance under varying pressure loads.

Main Results:

• The optimized film exhibits a high quasi-static piezoelectric charge coefficient (d33) of 52.2 pC N⁻¹ and voltage constant (g33) of 74.8 mV m N⁻¹.
• The sensor demonstrates stable signal output across an exceptionally broad pressure range (8.95 kPa to 3.06 MPa), with a rapid response time (18.1 ms) and durability (>10,000 cycles).
• A seven-channel integrated sensing system was developed for lower-limb biomechanical monitoring.

Conclusions:

• The nacre-inspired hierarchical interfacial architecture enables flexible piezoelectric sensors to withstand high compressive loads (megapascal regime) without response saturation.
• The developed sensor technology offers a practical solution for reliable, broad-range pressure sensing and wearable biomechanical monitoring applications.
• This approach provides a viable pathway for advancing flexible piezoelectric devices in health management and other fields requiring sensitive pressure detection.