On the Mechanical Properties of Graphyne, Graphdiyne, and Other Poly(Phenylacetylene) Networks

Abstract

We simulate, analyse and compare the mechanical properties of a number of molecular sheet‐like systems based on fully substituted, penta‐substituted, tetra‐substituted and tri‐substituted poly(phenylacetylene) using static force‐field based methods. The networks are modeled in a 3D environment with and without inter‐layer interactions in analogy to graphite and graphene respectively. It is shown that by varying the type of substitution and the length of the acetylene chain, one may control the mechanical properties of such systems. In particular, it is shown that poly(phenylacetylene) systems can be specifically designed to exhibit negative Poisson's ratio, and that the stiffness can be controlled in an independent manner from the Poisson's ratios. This is significant as it highlights the fact that such systems can be tailored to exhibit a particular set of mechanical properties.

Auxetics and Other Systems of Anomalous Characteristics

“…The theoretical paper presented by the Malta group, 'On the compressibility properties of the wine-rack-like carbon allotropes and related poly(phenylacetylene) systems' [15] looks at a number of carbon-based two-dimensional nano networks, some of which are shown to exhibit more than one negative mechanical property. This work, which extends earlier studies of the same authors, [16,17] shows how some of the networks can be both auxetic and exhibit negative linear compressibility.…”

On the Design of Multimaterial Honeycombs and Structures with T‐Shaped Joints Having Tunable Thermal and Compressibility Properties

“…This led to various studies in the last decades which were focused on the design and investigation of honeycombs specifically engineered to exhibit anomalous or superior thermomechanical properties, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] such as a negative Poisson's ratio (auxetic behavior). [8][9][10][11][12][13][14][15] Given the advantages of honeycombs over nonporous solids, [6,7,16,17] when put in the context of the developments which are being made on "negative thermomechanical properties," it is not surprising that research in the field of "negative honeycombs" is still the subject of extensive research. [3,4,9,11,17,30,31,[51][52][53][54][55] Previous studies [12,30,31,51,52] have shown some special characteristics of centrosymmetric honeycombs with T-shaped joints.…”

A Novel Mechanical Metamaterial Exhibiting Auxetic Behavior and Negative Compressibility

“…It is due to these enhanced properties and the wide range of applications that in recent years, there have been various studies which have attempted to design, model, synthesize, manufacture, or characterize materials and metamaterials which exhibit one or more of these anomalous properties. These include zeolites [11][12][13][14], silicates and other minerals [15], and polymeric systems [2,[16][17][18][19][20][21][22] which exhibit negative Poisson's ratios, in addition to metal organic frameworks (MOF) which exhibit negative linear compressibility [23][24][25]. In tandem, there has also been a significant amount of research aimed at exploring new mechanisms leading to anomalous behaviors.…”