Fabrication of helix–fiber composites with mechanically coupled core-wrapping for programmable properties

Abstract

Helix-fiber composites (HFCs), which involve wrapping a material around a flexible core, are of interest for intelligent stretchable functional materials or devices. Here, we reveal that mechanical coupling between the core and wrapping plays a critical role in controlling the structure and mechanical properties. Our results show that the mechanical properties of the HFC can be programmed by precisely tuning the mechanical coupling strength among them. Interestingly, the HFC also shows unique pseudo-elastic behavior under large strain due to the mechanical coupling effects. The HFC is demonstrated as an elastic metal conductor, programmable sensor, and finally as an elastic mold for structure transplantation by mechanically decoupling the elastomer core from the helix fiber. The results not only deepen the fundamental understanding of HFCs, but also may promote future structure-properties and fabrication studies on helix-structured functional composite and devices.