Polyurethane carbon fiber composite tubular electrode featuring three-dimensional interpenetrating conductive network

Flexible and stretchable electronics are important components in medical implantation, wearable durable devices and so on. However, conductive stability often conflicts with the mechanical stretchability in terms of decreased conductivity from the deformation. Here, we proposed a facile and effective strategy to construct a three-dimensional interpenetrating alignment configuration of conductive carbon fibers (CFs) during polyurethane (PU) tube extrusion by manipulating opposite-helical flows. With the benefits of the 3D-overlapping conductive network, the as-fabricated PU composite tubes were superior to convention-extruded ones with axial-flow driven 2D parallel-aligned configuration, with regard to higher initial conductivity, exceptional electrical stability under high strain, as well as excellent electrical reversibility in cycle loadings. The underlying working mechanism responding to mechanical deformation was well-established based on the transformation from contract conduction to tunneling one. As a promising practice application, the potential of the novel composite tube applied to thermal therapy was explored and it demonstrated that the composite tubes could produce high heating energy with characteristics of fast thermal response, low operation voltage and high stability under mechanical disturbance, via effective electric-thermal conversion. Accordingly, conductive stability-stretchability dilemma in the conventional stretchable electrode could be solved via simple one-step melt-process suitable for mass production. (C) 2018 Elsevier Ltd. All rights reserved.