High-resolution 3D printed strain sensor with superb stretchability and sensitivity: Unveiling the potential of melt electrowriting

Abstract

Recently, flexible strain sensors have attracted considerable attention due to their outstanding adaptability in applications such as human motion detection, health monitoring, and human–machine interaction. However, achieving strain sensors that integrate both high sensitivity and extensive stretchability remains a notable challenge. Herein, we employed melt electrowriting (MEW), a cutting-edge additive manufacturing technology, to fabricate a thermoplastic polyurethane (TPU) lattice with high-resolution and precisely designed structures. Subsequently, reduced graphene oxide (rGO) was deposited via layer-by-layer self-assembly to impart conductivity and leverage the substrate’s microstructure. Through optimizing structure and parameters, a flexible strain sensor with a high gauge factor (GF = 3,807.8) and a broad working range (up to 140%) has been achieved, representing an exceptional balance of sensitivity and stretchability. The sensor also shows remarkable durability with stable performance and negligible resistance variation after 5,000 cycles of stretching and releasing at 50% strain. Furthermore, the sensor can accurately detect diverse motions, from subtle swallowing actions to large-scale finger and knee bending, underscoring its significant potential for wearable electronics, and highlighting the transformative role of MEW in advancing this technology.