Direct-ink-writing printed multifunctional sensor array for simultaneous detection of strain, temperature and humidity

The direct-ink-writing (DIW) technology enables assembling novel sensors on structural surface by printing, which indicates a feasible way to non-destructively sense required signals from the attached structure. Although various novel sensors are printed by the DIW technology to pursue outstanding performance in a certain technical specification, the sensors with integrated multiple functions are highly desired but still challenging, especially aiming to detect different kinds of physical quantities. Here, we propose a novel design strategy for sensors to decouple different signals including the strain, temperature and humidity. Accordingly, the multifunctional sensor array is printed by DIW using commercial graphene-based inks. The outstanding performance for the obtained sensor array is experimentally validated which shows potential application in some non-destructive sensing requirements under multifield action. This work provides insight for multifunctional sensors including design, DIW fabrication and array assembly.