Page 17 - Carbon Nanotube Fibres and Yarns

Introduction 9

yarn manufacture and post-spinning treatments. Chapter 7 discusses the
structures of CNT fibers and yarns manufactured by different methods and
how their structures affect the mechanical, electrical, and thermal properties
of the final fibers and yarns.
Chapter 8 reviews mechanics models of CNT yarns. General analytic
models only predict qualitatively the stress distribution inside the yarn and
the trends of twist-dependent yarn performances, like in conventional tex-
tile yarn mechanics. Inter-tube sliding determines the precise mechanics of
a dry CNT bundle in the yarn, which can be simulated using molecular dy-
namics. To deal with the large number of nanotubes in a yarn, coarse-grained
molecular dynamics is employed to study the microstructural evolution of
the CNT structure. Multi-scale modeling is becoming an increasingly im-
portant tool to deal with the hierarchical structure of CNT yarns.
CNTs have superior mechanical, electrical, and thermal properties but
their nanoscale dimensions restrict their applications. CNT yarns, being mi-
croscopic and continuous assemblies of CNTs, offer high potential for the
development of applications. These multifunctional properties distinguish
CNT yarns from textile fibers and metal wires, opening up the possibility
of manufacturing a wide range of smart textile constructions. Part 3 reviews
some of these applications, including sensing, energy storage, and artificial
muscles.
CNT yarns are piezo-resistive, which can be utilized for strain mea-
surement, material damage detection, torque measurement and motion
monitoring, as well as temperature measurement and detection of various
chemicals. Chapter 9 presents the operating principles of CNT yarn sensors
and experimental results.
Flexible threadlike supercapacitors with high flexibility, tiny volume,
and good specific performance have attracted extensive attention re-
cently due to their potential in wearable electronics and smart textiles.
CNT yarns have the advantages of high surface area, low mass den-
sity, outstanding chemical stability, and excellent electrical conductivity
and thus are excellent electrode materials for threadlike supercapacitors.
Chapter 10 discusses recent progresses in charge storage mechanisms,
active materials, electrolytes, designs of threadlike architecture, and self-
charging supercapacitors.
CNT yarns are also promising candidates for flexible actuators, also
known as artificial muscles. Chapter 11 presents a brief review on the types
of CNT yarn-based actuators developed in recent years and their energy
conversion mechanisms, performance metrics, and potential applications.