Structurally hierarchical flex-sensor of MWCNTs/TPU composite via mesh mould-based selective laser sintering (SLS) and ultrasonic cavitation-enabled treatment (UCT)

Abstract

• Structurally hierarchical MWCNTs/TPU flexible strain sensors were designed. • Selective laser sintering (SLS) with inverted-mould grooving produced sensors. • Ultrasonic cavitation-enabled treatment (UCT) fabricated a grass-like structure. • Sensor hierarchical structure-determined sensing mechanisms were dissected. • The sensor exhibited detecting surface curvatures and monitoring finger action. The piezoresistive performances of conductive polymer composites (CPCs) largely depend on the material composition and fabrication process. A structurally hierarchical flexible strain sensor of a multi-walled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) CPC was prepared via a simple hybrid fabrication path including selective laser sintering (SLS) 3D printing, inverted-mould grooving, and ultrasonic cavitation-enabled treatment (UCT). The influences of SLS process parameters, mesh-molded groove geometry, and material ratio on the sensor properties were studied. The sensing mechanisms were discussed. Some application demonstrations of the prepared sensors were exhibited. The hierarchically structural design and fabrication path facilitate the development of more versatile flex-sensors.