High‐Performance 3D Printed Thermoplastic Polyurethane Composite Resistive Flexible Strain Sensor

ABSTRACT Strain sensor, valued for their elasticity and versatility, have gained significant attention for application in human and robotics monitoring. Here, the flexible strain composite sensor fabrication process uses a dual extruder FDM 3D printer with thermoplastic polyurethane (TPU) and electric‐conductive thermoplastic polyurethane (E‐TPU) filament material, which consists of a “flat flexible covering” of pure TPU and a “mesh sensor component” of conductive TPU. The research prioritized design, fabrication, strain‐sensing behaviors, and deformation of the TPU/E‐TPU‐made composite flexible strain sensors. As a result, the flexible composite sensors achieve significantly enhanced performance, 250% stretchability, exceptional sensing ability (compression, bending, and twisting), and durability under various deformations. The strain rate at 50, 70, and 100 mm/min affects the stress at break point (13.5, 16.4, and 25.5 MPa), strain at break (310%, 300%, 290%), and strain at yield point (9%, 12%, and 13%), respectively. Carbon (35% atomic C, 33% weight C) have exceptional mechanical properties, comprising strength, stability, and toughness, per SEM‐EDS and microstructural investigations. The flexible strain composite sensors indicate significant potential for practical wearable and soft robotics applications after real‐time testing.