Ultrasound directed self-assembly processing of nanocomposite materials with ultra-high carbon nanotube weight fraction

Abstract

We introduce a new process to manufacture polymer nanocomposite materials reinforced with an ultra-high weight fraction of aligned carbon nanotubes. This process is based on using ultrasound directed self-assembly, which employs the force associated with a standing ultrasound wave to concentrate and align carbon nanotubes dispersed in the polymer matrix. In contrast with existing manufacturing processes, which typically limit the carbon nanotube weight fraction to approximately 1 wt.%, we demonstrate manufacturing polymer nanocomposite materials with more than 10 wt.% of aligned carbon nanotubes along a single line. We accomplish this by first dispersing 1 wt.% percent of carbon nanotubes in the polymer matrix, and using ultrasound directed self-assembly to concentrate and align the carbon nanotubes along a single line. Then, we trim the excess material around the single line of aligned carbon nanotubes to retain a nanocomposite material with an ultra-high weight percent of aligned carbon nanotubes. We also manufacture polymer nanocomposite materials with different weight percent of aligned carbon nanotubes along multiple parallel lines, and with randomly oriented carbon nanotubes. We experimentally measure the mechanical properties of the polymer nanocomposite materials, and find that the ultrasound directed self-assembly process results in specimens with aligned carbon nanotubes that display a significant increase in ultimate tensile strength, Young’s modulus, and moduli of resilience and toughness, compared to benchmark materials including polymer nanocomposite materials with randomly oriented carbon nanotubes, and virgin polymer matrix material.