Ultra-Stretchable and Skin-Conformal Piezoelectric Electronic Skin for Self-Powered Human Motion Monitoring

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Electronics

Background:

• Soft piezoelectric electronic skins require high stretchability and efficient stress transfer for reliable performance during joint bending.
• The mechanical and electrical properties of piezoelectric composites are significantly influenced by the polymer matrix composition and filler loading.

Purpose of the Study:

• To investigate the effect of polydimethylsiloxane (PDMS) matrix composition and barium titanate (BaTiO3) loading on the performance of piezoelectric electronic skins.
• To optimize the BPPE-skin for enhanced stretchability, stress transfer, and voltage output for wearable applications.

Main Methods:

• Fabrication of BaTiO3/PDMS piezoelectric electronic skin (BPPE-skin) using a blade-coating method.
• Systematic variation of PDMS base-to-curing-agent ratio (5:1 to 30:1) and BaTiO3 loading (10 to 90 wt%).
• Mechanical characterization using tensile tests and electrical response evaluation under bending motions.

Main Results:

• Increasing the PDMS base-to-curing-agent ratio improved stretchability but reduced stress transfer efficiency, with optimal voltage output at a 10:1 ratio.
• Higher BaTiO3 loading (up to 90 wt%) significantly enhanced voltage output due to increased active piezoelectric particles.
• The optimized BPPE-skin (90 wt% BaTiO3, 10:1 PDMS ratio) demonstrated good flexibility and conformal attachment to various body joints.

Conclusions:

• The composition of the PDMS matrix and the loading of BaTiO3 are critical factors in optimizing piezoelectric electronic skin performance.
• The developed BPPE-skin shows potential for creating effective, self-powered wearable sensors for monitoring human joint motion.
• Distinct voltage patterns generated during bending of knee, elbow, wrist, and fingers highlight the device's sensitivity and applicability.