Role and impact of surfactants in carbon nanotube dispersions and sorting

Abstract

Carbon nanotubes (CNTs) are proving to be versatile nanomaterials that exhibit superior and attractive electrical, optical, chemical, physical, and mechanical properties. Different kinds of CNTs exist, and their associated properties have been actively explored and widely exploited from fundamental studies to practical applications. Obtaining high‐quality CNTs in large volumes is desirable, especially for scalable electronic, photonic, chemical, and mechanical systems. At present, abundant but random CNTs are synthesized by various growth methods including arc discharge, chemical vapor deposition, and molecular beam epitaxy. An economical way to secure pristine CNTs is to disperse the raw soot of CNTs in solutions, from which purified CNTs are collected via sorting methods. Individual CNTs are generally hydrophobic, not readily soluble, requiring an agent, known as a surfactant to facilitate effective dispersions. Furthermore, the combination of surfactants, polymers, DNA, and other additives can enhance the purity of specific types of CNTs in confidence dispersions. With highly‐pure CNTs, designated functional devices are built to demonstrate improved performance. This review surveys and highlights the essential roles and significant impacts of surfactants in dispersing and sorting CNTs.

Stable dispersion of carbon nanotubes in a molten salt of KNO3–NaNO3–NaNO2–LiNO3–LiOH

“…However, CNTs are nonpolar molecules in terms of molecular structure, and they do not dissolve in almost all solvents. 8 Through the use of strong oxidizing acids or other strong oxidizer technology, the surface of the CNTs can be introduced to hydrophilic functional groups such as hydroxyl, carboxyl, and sulfonic acid. 9,10 Following further mechanical force, CNTs can be well dispersed, such as into pastes.…”

A Sensitive Strain Sensor Based on Multi-Walled Carbon Nanotubes/Polyaniline/Silicone Rubber Nanocomposite for Human Motion Detection

“…Considering CNTs are often dispersed randomly within the polymer matrix, extensive research has been conducted to achieve a directed and uniform distribution of CNTs. However, effectively dispersing CNTs within a polymer matrix presents challenges [15,16]. Furthermore, the connection between CNTs and polymers in composites, as well as related measurements, necessitates further advancements and refinement.…”