Density dependence of elastic properties of graphynes

TL;DR

This paper investigates how the elastic properties of graphynes vary with density, revealing that their elastic moduli are less density-dependent than typical porous materials, with implications for their structural behavior.

Contribution

It extends previous elastic property calculations of graphynes by analyzing the density dependence and comparing it to porous materials, providing new insights into their mechanical behavior.

Findings

Elastic moduli of graphynes are less dependent on density than porous materials.

The density dependence follows a power law with an exponent less than 2.

Pore shape influences the elastic properties of graphyne structures.

Abstract

Graphyne is a two-dimensional carbon allotrope of graphene. Its structure is composed of aromatic rings and/or carbon-carbon bonds connected by one or more acetylene chains. As some graphynes present the most of the excellent properties of graphene and non-null bandgap, they have been extensively studied. Recently, Kanegae and Fonseca reported calculations of four elastic properties of 70 graphynes, ten members of the seven families of graphynes [Carbon Trends 7, 100152 (2022)]. They showed that the acetylene chain length dependence of these properties can be simply modelled by a serial association of springs. Here, based on those results, we present the density dependence of these properties and show that the elastic moduli, $E$, of graphyne are less dependent on density, $\rho$, than porous cellular materials with an exponent of $E \sim \rho^{n}$, smaller than 2. We discuss the results in terms of the shape of the pores of the graphyne structures.