Which of the following statements correctly describes the unique properties and potential applications of Carbon Nanotubes (CNTs) in advanced technology?
Show answer & explanation
Correct answer: B
Explanation
Solution: The correct answer is Single-walled Carbon Nanotubes (SWCNTs) possess tunable electrical properties that can be either metallic or semiconducting depending on their chirality and diameter, making them promising materials for nanoelectronics and sensor applications.
Explanation:
☛ Carbon Nanotubes (CNTs) are cylindrical structures consisting of rolled-up sheets of single-layer carbon atoms known as graphene.
☛ Single-Walled Carbon Nanotubes (SWCNTs): These consist of a single cylindrical graphene layer. Their electronic behavior is uniquely governed by their chirality (the geometric direction in which the graphene sheet is rolled) and diameter.
☛ Depending on this chiral angle, SWCNTs can act either as a metal (conducting electricity better than copper) or as a semiconductor (comparable to silicon), making them vital for nanoelectronics, high-speed transistors, and chemical sensors.
☛ CNTs are characterized by extremely high tensile strength, superior thermal conductivity, and chemical stability under ambient conditions.
Extra Exam-Relevant Facts:
☛ Discovery: Carbon nanotubes were extensively characterized and brought to global attention by Japanese physicist Sumio Iijima in 1991.
☛ Types of CNTs: They are primarily classified into Single-Walled Carbon Nanotubes (SWCNTs) and Multi-Walled Carbon Nanotubes (MWCNTs), which consist of multiple concentric graphene cylinders.
☛ Thermal Conductivity: Unlike common insulators, CNTs exhibit an exceptionally high thermal conductivity along their tube axis, comparable to or exceeding that of diamond.
☛ Mechanical Strength: CNTs have a tensile strength that is dozens of times greater than steel while having only a fraction of its weight.
Important One-Liners for Upcoming Exams:
☛ Who is widely credited with the detailed discovery of carbon nanotubes in 1991? → Sumio Iijima
☛ Which hybridisation state of carbon atoms is present in carbon nanotubes? → sp² hybridisation
☛ Which allotrope of carbon consists of a single layer of hexagonal carbon atoms? → Graphene
☛ What hollow spherical allotrope of carbon is composed of 60 carbon atoms? → Buckminsterfullerene (C₆₀)
☛ What geometric property dictates whether a carbon nanotube is metallic or semiconducting? → Chirality (Chiral vector)