Hierarchical composites containing carbon nanotubes

Abstract

Hierarchical composites containing carbon nanotubes (CNTs) have the potential to possess improved multifunctional properties as well as unique sensing/active capabilities due to the inherent properties of CNTs (i.e., mechanical, electrical, and thermal). The purpose of this chapter is to review the current state of the art in this research area and highlight opportunities for future research. Specifically, three construction schemes used to produce CNT hierarchical composites are reviewed: dispersed systems, fiber coatings, and CNT structures. In these construction schemes, CNTs are used as a performance additive to reduce matrix mobility, as a sizing to improve adhesion between the matrix and the microscale fiber, and as the building blocks of structures such as fibers to more fully exploit the mechanical properties of CNTs, respectively. To date, research results have indicated that these strategies produce composites with improved properties, and most frequently those improved properties are mechanical properties such as strength, modulus, and fracture toughness. Based on these results, further activities aimed at understanding these property increases in terms of modeling as well as more research activity aimed at producing CNT fibers and exploiting other CNT properties will lead to improved approaches to composite design which merit the routine use of CNTs in structural composites.