Piezoresistive sensor with high sensitivity and wearable flexibility based on three-dimensional (3D) porous cavernous structure inspired by volcanic rock

With the continuous advancement of Internet of Things(IoT) technology, flexible pressure sensors have been extensively researched as core components of wearable devices. However, achieving high sensitivity without compromising stability remains a challenge for most sensors. Inspired by volcanic stone, this paper reports a three-dimensional porous microstructural design termed "volcanic stone" and successfully fabricates a flexible porous piezoresistive sensor based on MWCNTs/PDMS using sugar cubes as a sacrificial template.The multi-layered structure formed by this method exhibits a large pore architecture on the scale of hundreds of micrometers. It features a hollow framework ranging from sub-micrometer to micrometer dimensions. Irregular pores are distributed across the skeleton, adding structural complexity at the microscale. ‌The arrangement of this structure is conducive to establishing a highly interconnected conductive network. The sensor can be used to monitor body motion and some subtle vital signs. Here, we demonstrate a flexible pressure sensor that has excellent stability and outstanding durability. Notably, it maintains a 95% cycle retention rate after 8,750 cycles and achieves ultrahigh sensitivity (up to 395.53 kPa⁻ 1 at 0–9 kPa and 979.39 kPa⁻ 1 at 9–14 kPa). The response and unloading times were both 200 ms. And it had excellent bending and torsion properties, with an elastic deformation of 400%. It significantly improves the monitoring performance and has broad application prospects in healthcare, human–computer interaction, and other fields.