Achieving a continuously adjustable micro-nanostructure of sensing materials is crucial and still a challenge for the flexible pressure sensor. We proposed a new method to prepare ultrathin ordered nanocone array films by designing tunable tapered anodized aluminum oxide templates and to prepare highly sensitive flexible pressure sensors by the interlocking nanocone arrays. Meanwhile, the theoretical prediction model of the sensitivity of interlocked nanocone arrays is proposed, and its result shows that the resistance change rate is positively correlated with the height of interlocked nanocone arrays and the contact area between interlocked nanocones. According to the finite element simulation and experimental results, the interlocked ordered nanocone array pressure sensor exhibits a high sensitivity of 268.36 kPa-1 in the pressure range of 0-200 Pa, an ultralow detection limit of 0.98 Pa, a fast response/recovery time of 48/56 ms, a low hysteresis of ±3.156%, stability under 5000 cycles of loading, and continuity and repeatability under different loads and loading speeds. Furthermore, the pressure sensor can accurately monitor weak wind velocities, wrist torsion and bending movement, and book opening and closing angles. The sensor has broad application prospects in wearable medical monitoring, electronic skin, and human-computer interaction.
Keywords: flexible piezoresistive sensor; interlocked structure; ordered nanocone array; sensitivity simulation; t-AAO.