ABSTRACT
The excellent electronic and mechanical properties of individual carbon nanotubes (CNTs) have led to the development of one-, two-, or three-dimensional structures composed of CNTs including fibers, films or sheets, and arrays or foams. These structures could be used in microscale and macroscale applications, unlike individual CNTs. CNT fibers or yarns constitute long and continuous arrangements of intertwined or interlocked CNTs that are highly packed, mostly aligned, and parallel to one another (Figure 14.1). CNT fibers contain thousands of CNTs in their cross-sections, and their electrical, thermal, and mechanical properties depend not only on the corresponding properties of the CNTs themselves but also on the relative arrangements among the CNTs within the fiber. These CNT fibers could have much higher specific elastic modulus and specific tensile strength than those of existing commercial carbon and polymeric fibers. Furthermore, CNT fibers exhibit also satisfactory electrical and thermal conductivities, although at least two orders of magnitude lower than those of CNTs themselves. A key feature of CNT fibers is their continuity, which makes them very amenable for a wide range of applications, including electricity transmission, sensing, reinforcement, energy storage, actuation, and many others. Several excellent articles have been published in the past few years reviewing the fabrication and performance of CNT fibers and they serve as a reference in this chapter (Lu et al. 2012; Park and Lee 2012; Miao 2013; Lekawa-Raus et al. 2014a). The fabrication methods of CNT fibers are presented in Section 14.2, including spinning or drawing from CNT solutions, arrays, and aerogels and others. The mechanical response of the CNT fibers is presented in Section 14.3 and discussed in terms of the parameters that affect that response. Sections 14.4 and 14.5 present the electrical and piezoresistive responses,
14.1 Introduction ...................................................................................... 357 14.2 Fabrication .........................................................................................358 14.3 Mechanical Response .......................................................................362
