Long-term stability and durability of direct-ink-writing 3D-printed sensors: challenges, strategies and prospects

The direct-ink-writing (DIW) 3D-printed sensors have shown tremendous potentials in various fields, owing to their outstanding performances and simplified manufacturing process. Most of the existing studies have mainly focused on achieving higher stretchability and superior sensitivity, while few works devoted to obtain the long-term stability and durability. As a result, although various DIW sensors exhibit distinguished functions, there are still lack of successful applications in practical engineering. Accordingly, this review seeks to bring the challenges of long-term stability and durability to the forefront in this field. Firstly, the influential factors and respective mechanisms for both challenges are explored. Subsequently, potential strategies were analysed to enhance the long-term stability and durability for DIW sensors, including the ink innovation, sensor-structural design and printing process optimisation. Finally, the urgent requirements, interdisciplinary route and long-term applications are prospected. This paper provides insight for the DIW sensors in addressing the challenges of long-term stability and durability for promoting them to real engineering applications.