A mini-review on dispersion and functionalization of boron nitride nanotubes

Abstract

Boron nitride nanotubes (BNNTs) are of intense scientific interest due to their unrivaled physicochemical characteristics, extraordinary thermal, electronic, mechanical, optical properties, and prospective applications in various nanotechnologies. Therefore, they are particular candidates for the development of new materials potentially applied in abundant applications. However, obtaining homogenous composite materials requires a good dispersion of BNNTs, as well in solvents or in the matrix, which still has remained challenging. The preparation of effective dispersions of BNNTs presents a major impediment to the extension and utilization of BNNTs. BNNTs intrinsically tend to bundle and/or aggregate. The prevention of such behavior has been explored by testing various techniques to improve the dispersibility of BNNTs in a variety of solvents. There are mainly two approaches to obtain a good quality dispersion; chemical functionalization and physical interactions. The chemical functionalization technique has been found effective, but deteriorates the intrinsic properties of BNNTs through the introduction of defects on the wall. Physical blending approaches with the ultrasound and high-speed shearing have been proven capable of debundling BNNTs and stabilizing individual BNNTs while maintaining their integrity and intrinsic properties. Attention has been brought to the study of the dispersion of BNNTs in aqueous media and most attention is paid to molecular dynamics (MD) simulation techniques and other physical techniques, as well as to the use of various surfactants and polymers.