Upscaling mechanical properties of Al2O3 coated VACNT forest architecture under compression

Effect of oxide coating thickness and strain rate on mechanical properties of vertically aligned carbon nanotubes (VACNT) forest and patterned pillars have been investigated using flat punch nanoindentation. The elastic modulus of 20 nm oxide coated VACNT forest and micro-pillars show a remarkable increase of 135 times and 77 times respectively as compared to uncoated CNT forest samples. Large enhancement in load carrying capacity of oxide-coated VACNT is observed when the strain rate is varied from 50 nm/s to 4000 nm/s in micro compression tests. The elastic strain energy density of the 20 nm coated VACNT forest is estimated to be ~260 times higher than the as-grown VACNT forest. Patterned CNT pillar with coating of 20 nm Al2O3 shows 77 times increment with the strain rate. •Flat punch nanoindentation is performed on Al2O3 coated vertically aligned carbon nanotubes forest.•Elastic modulus of 20 nm oxide coated VACNT forest is increased by 135 times compared to uncoated forest.•The enhancement of elastic strain energy density of the 20 nm coated VACNT forest at 4000 nm/s is ~260 times higher.•Elastic modulus of 20 nm oxide coated patterned VACNT architecture is enhanced by 77 times.