Short Poster Lecture
Structures from nature are often hierarchical composites, in which nanosized fillers (fibers or platelets) are embedded in matrices. In this work, we present an unconventional multi-scale, i.e. nano-micro-macro, hierarchical composite based on the newly emerged carbon nanotube fibers (CNTFs), the structure of which is reminiscent of that of tendon. The interphase was controlled by applying different levels of densification treatments to the CNTFs prior to embedding in an epoxy matrix. The results show strong effects of the solvents on the structure and chemistry of the CNTFs, and consequently on the interphase of the hierarchical composites. A continuously monitored fragmentation test showed that the apparent interfacial shear strength could be doubled by the treatment. We demonstrate that interphase between CNTF and epoxy can be controlled by polymer penetration, which will certainly affect the mechanical properties of the composite.