Direct Measurements of the Young's Modulus of a Single Halloysite Nanotube Using a Transmission Electron Microscope with a Bending Stage

Abstract

Halloysite nanotubes (HNTs) are a naturally occurring nanotubular aluminosilicate mineral, which has been used to prepare nanocomposites with exceptional mechanical properties. In order to understand the roles of nanotubes during the deformation and fracture of nanocomposites, a state-of-the-art transmission electron microscope (TEM) with a bending stage was used to measure the Young's modulus of individual HNTs. TEM micrographs showed that the HNTs were surprising flexible and could be bent to almost 90 degrees without fracture. There was no observable reduction in the cross-sectional area of the bent HNTs. The findings suggest that HNTs, as a nanofiller, have a good potential to be used in high-performance structural materials, especially polymer-based nanocomposites.

Properties and applications of halloysite nanotubes: recent research advances and future prospects

“…When the external diameter of Hal ranged between 50 and 160 nm, the average elastic modulus was 140 GPa. This result is in agreement with the observation made by Lu et al (2010). When the external diameter of Hal was less than 50 nm, the elastic modulus suddenly increased to 460 GPa.…”

“…Abdullayev et al (2012) estimated that the Hal bending stiffness and tensile strength were reduced due to the decrease in wall thickness resulting from the acid treatment. However, a more accurate evaluation of the effects of the acid treatment on the change in the mechanical properties of Hal could be achieved only by directly measuring the Young's modulus of Hal using proposed methods based on TEM (Lu et al, 2010) and atomic force microscopy (AFM) (Lecouvet et al, 2013a). The aforementioned studies revealed the stability of Hal in acid or alkaline solutions, which is meaningful for the understanding of the behavior of Hal in natural environments, e.g., how its surface reactivity is possibly modified in acidic soils.…”

“…This discrepancy arises from the different diameters of the zigzag (15-36 Å) and of the armchair (21-46 Å) Hal. Lu et al (2010) directly measured the Young's modulus of a single Hal nanotube by using a TEM with a bending stage. The obtained experimental Young's modulus (130 ± 24 GP) is lower than the calculated value for the single-walled Hal (230-340 GPa) because Hal is composed of multi-walled nanotube rolled by 15-20 aluminosilicate layers (Lvov et al, 2008) including structural defects.…”

Structural and mechanical behaviour of LLDPE/HNT nanocomposite films

“…At first glance, it might seem like a negative effect. Nevertheless, based 4,0x10 5 6,0x10 5 8,0x10 5 1,0x10 6 1,2x10 6 Intensity …”

“…The empirical formula is Al2(OH)4Si2O5(2H2O). HNT do not reach such high modulus of elasticity as CNT (up to 1TPa) [1], but still reach a very high values around 130 GPa [6]. Another advantage is that HNT have a better dispersion in large number of polymer systems in comparison with a commercially used organoclays.…”