Effect of nanofiber proximity on the mechanical behavior of high volume fraction aligned carbon nanotube arrays

The effect of nanofiber proximity on the mechanical behavior of nanofiber arrays with volume fractions (Vf) from 1% to 20% was quantified via nanoindentation of an aligned carbon nanotube (A-CNT) array. The experimental results show that the indentation modulus for A-CNT arrays has a highly non-linear scaling with the CNT Vf, leading to modulus enhancements of up to ∼600× at Vf = 20%. Modeling illustrates that the origin of the highly non-linear trend with Vf is due to the minimum inter-CNT spacing, which is shown to be more than an order of magnitude larger than the graphitic spacing.