Energy-efficient all fiber-based local body heat mapping circuitry combining thermistor and memristor for wearable healthcare device

Abstract

This study demonstrated a wearable and flexible temperature sensing circuitry for a diagnosis of skin temperature. This system is based on a novel carbon nanotubes (CNTs)-based temperature sensor (CTS) array, built on cotton yarn using a mixture of multi-walled (MW)-CNTs and PDMS (polydimethylsiloxane). To divide and select the unit thermistors, a memristor which operates in the normally-off state was utilized. To construct the memristors, an Al precursor-based solution dip coating method and initiated chemical vapor deposition (iCVD) were employed for the metal electrode and resistive switching layer (RSL), respectively. Using the aforementioned processes, aluminum (Al) electrode and poly (ethylene glycol methacrylate, pEGDMA)-RSL layers were deposited on a cotton yarn backbone. A unit temperature sensor based on the proposed circuitry was fabricated by intersecting the Al/pEGDMA-coated yarns to both sides of the CTS wire, while forming a 1-thermistor and 2-memristor (1T-2M). This architecture exhibited promising performance as a sensor-array system for a fully fabric-based wearable healthcare device.