ABSTRACT
The alignment of carbon nanotubes (CNTs) represents a general and ef cient strategy to extend their remarkable electrical, mechanical, thermal, and optical properties to a macroscopic scale that is required for many practical applications (Dai et al. 2003, Liu et al. 2011, Sun et al. 2012a). Over the past decade, signi cant efforts have been made to align CNTs by various in situ and ex situ techniques. The direct growth of CNT array is the most effective way to obtain neat aligned CNTs. Other macroscopic CNT assemblies, for example, CNT sheets and CNT bers, can be further spun from the arrays and be easily engineered under various conditions. Although great progress have been made in aligned arrays of both multiwalled carbon nanotube (MWCNT) (Fan et al. 1999) and single-walled carbon nanotube (SWCNT) (Hata et al. 2004), all spinnable arrays for aligned sheets and bers are still on the basis of MWCNTs synthesized by chemical vapor deposition (CVD). Due to the highly aligned and porous structure, aligned CNTs can be incorporated with a lot of polymers to fabricate composite materials without alignment destruction, and the resulting composites exhibit more dramatically enhanced physical properties than traditional randomly dispersed CNTs (Huang et al. 2011, Li et al. 2011, Sun et al. 2012a, 2013b). In addition, the synergetic interactions between aligned CNTs and polymers have been found to create some new sensing properties different from any individual component. In this chapter, the synthesis of aligned CNT materials will be rst summarized. The properties of aligned CNTs are then introduced with a highlight of electromechanical properties of CNT ber for arti cial muscles. The incorporation of functional polymers into the aligned CNTs is nally emphasized to develop novel chromatic and deformable composite materials. The challenge and application of aligned CNT-based sensing materials will be also described.
