Mechano and thermo-mutable anisotropy of a multifunctional, porous 3D nanostructure: simulation and 3D printing

Tensile Testing of a 3D printed specimen exhibiting extreme ductility ( > 45%) owing to the synergistic cooperation of sheets, tubes and conjunctions.

One-dimensional (1D) Boron Nitride nanotube (BNNT) and 2D hexagonal BN (h-BN) are attractive for demonstrating fundamental physics and promising applications in nano/microscale devices. However, there is a high anisotropy associated with these BN allotropes as their excellent properties are along the tube axis or in-plane direction. We study a series of 3D BN prototypes, namely Pillared Boron Nitride (PBN), by fusing single wall BNNT and monolayer h-BN aimed at filling this gap. We use Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations to probe the diverse mechano- and thermo-mutable properties of PBN prototypes, followed by 3D printing and tensile mechanical experiments. Our results demonstrate that the synergistic behavior of the junctions, tubes and sheets in PBN overcomes the intrinsic limitations of its constituents, and amplifies superior characteristics including 3D balance of strength, toughness and thermal transport, emergence of negative Poisson’s ratio, and elimination of strain softening. These features, combined with porous and lightweight structure, render PBN as a 3D multifunctional template for applications in graphene-based nanoelectronics, optoelectronics, gas storage and functional composites.