Flexible Strain Sensors Fabricated by Fused Deposition Modeling-Based Multimaterial 3D Printing with Conductive Polyurethane Composites*

Flexible strain sensors have attracted much attention due to their excellent stretchability, conformability and ability to measure large deformations. These sensors have found a wide range of applications, including health tracking, human-machine interaction, and human motion monitoring. However, current mass-production methods do not support the small-batch customization of flexible strain sensors, and the additional mounting step reduces the structural integrity. This paper presents a widely accessible approach for the rapid fabrication of flexible strain sensors that are directly printed onto objects in an on-demand and reliable manner by exploring the multimaterial fused deposition modeling techniques and optimizing the composition of functional filaments. Furthermore, the feasibility and effectiveness of the proposed method are demonstrated in the development of customized, flexible strain sensors that have complex sensing patterns and geometries.