Additive Manufacturing of Stretchable Polyurethane/Graphene/Multiwalled Carbon Nanotube-Based Conducting Polymers for Strain Sensing

The current flexible sensor plays an indispensable role in human health monitoring, and the development of high-performance sensors requires the advantages of materials and structures. The purpose of this study is to use digital light processing (DLP) to prepare flexible sensors with pore structures by dispersing the two fillers in the thermoplastic polyurethane (TPU) light-sensitive resin. This study uses graphene (GN) and multi-wall carbon nanotubes (MWCNTs) as the addition of flexible resin materials for phase-based preparation, and uses digital optical curing treatment technology to achieve rapid preparation of flexible sensors with special porous structures. Results showed that 1.2 wt % MWCNTs-GN/TPU material showed excellent sensing performance. The resistivity of the composite is 1.74 × 104 Ω cm. The sensitivity coefficient was 1.8464; the ductility was 45%; and the low lag coefficient was only 9%. The preparation of porous flexible sensors has higher sensitivity and more suitable for human body. This method is expected to provide new ideas for the rapid formation of flexible sensors.