Large-Area Conductor-Loaded PDMS Flexible Composites for Wireless and Chipless Electromagnetic Multiplexed...

Area of Science:

• Materials Science
• Electrical Engineering
• Sensor Technology

Background:

• Capacitive dielectric sensors offer potential for temperature monitoring.
• Polydimethylsiloxane (PDMS) is a versatile polymer for sensor fabrication.
• Conductive fillers can enhance the dielectric properties of polymers.

Purpose of the Study:

• To develop and characterize novel capacitive dielectric temperature sensors.
• To investigate the performance of PDMS-based sensors with conductive fillers.
• To demonstrate a wireless sensing platform for remote temperature detection.

Main Methods:

• Fabrication of PDMS-based capacitive sensors with copper, graphite, and milled carbon fiber fillers.
• Testing sensor response across a temperature range of 20-110 °C and frequencies of 0.5-200 MHz.
• Interrogation of sensors using wirelessly coupled chipless resonant coils and a NanoVNA.

Main Results:

• PDMS-CF capacitors exhibited enhanced sensitivity between 20-60 °C, with a relative response of 85.5% at 200 MHz.
• The wireless sensing platform demonstrated an average sensitivity of 0.38% °C⁻¹, a 40x improvement over pristine PDMS.
• The system showed good agreement with VNA measurements, stable performance across distances and humidity, and a scalable multiplexed array.

Conclusions:

• PDMS-CF composite materials are effective for developing sensitive capacitive dielectric temperature sensors.
• The developed wireless sensing platform provides a low-cost, portable, and high-performance solution for temperature monitoring.
• The technology enables scalable, multiplexed spatial temperature detection with a reversible dynamic response.