Multiwall Carbon Nanotubes: A Review on Synthesis and Applications

MWCNTs are elongated cylindrical nanoobjects made of sp2 carbon. They have a diameter of 3–30 nm and can grow to be several centimetres long. Therefore, their aspect ratio can range between 10 to 10 million. Carbon nanotubes are the foundation of nanotechnology. It is an exceptionally fascinating material. CNTs possess excellent properties, such as mechanical, electrical, thermal, high adsorption, outstanding stiffness, high strength and low density with a high aspect ratio. These properties can be useful in the fabrication of revolutionary smart nanomaterials. The demand for lighter and more robust nanomaterials in different applications of nanotechnology is increasing every day. Various synthesis techniques for the fabrication of MWCNTs, such as CVD, arc discharge, flame synthesis, laser ablation, and spray pyrolysis, are discussed in this review article, as are their recent applications in a variety of significant fields. The first section presents a brief introduction of CNTs, and then the descriptions of synthesis methods and various applications of MWCNTs in the fields of energy storage and conversion, biomedical, water treatment, drug delivery, biosensors, bucky papers and resonance-based biosensors are provided in the second section. Due to their improved electrical, mechanical, and thermal properties, MWCNTs have been extensively used in the manufacturing and deployment of flexible sensors.