Bio-Inspired Aggregation Control of Carbon Nanotubes for Ultra-Strong Composites

TL;DR

This paper introduces a bio-inspired aggregation control method for carbon nanotubes, enabling the creation of ultra-strong, well-aligned nanocomposites with significantly enhanced tensile strength and toughness.

Contribution

It presents a novel bio-inspired strategy to limit CNT aggregation to sub-50 nm, resulting in highly packed, aligned, and unaggregated composites with exceptional mechanical properties.

Findings

Achieved tensile strengths up to 6.94 GPa, more than double that of traditional carbon fiber composites.

Demonstrated a bio-inspired aggregation control that maintains CNT dispersion at sub-50 nm.

Produced composites with toughness up to 192 MPa, indicating high durability.

Abstract

High performance nanocomposites require well dispersion and high alignment of the nanometer-sized components, at a high mass or volume fraction as well. However, the road towards such composite structure is severely hindered due to the easy aggregation of these nanometer-sized components. Here we demonstrate a big step to approach the ideal composite structure for carbon nanotube (CNT) where all the CNTs were highly packed, aligned, and unaggregated, with the impregnated polymers acting as interfacial adhesions and mortars to build up the composite structure. The strategy was based on a bio-inspired aggregation control to limit the CNT aggregation to be sub 20--50 nm, a dimension determined by the CNT growth. After being stretched with full structural relaxation in a multi-step way, the CNT/polymer (bismaleimide) composite yielded super-high tensile strengths up to 6.27--6.94 GPa, more than 100% higher than those of carbon fiber/epoxy composites, and toughnesses up to 117--192 MPa. We anticipate that the present study can be generalized for developing multifunctional and smart nanocomposites where all the surfaces of nanometer-sized components can take part in shear transfer of mechanical, thermal, and electrical signals.