I was going through a recently published journal paper by ACS (Applied Nano Materials) about gas separation using nanoporous Graphene.
DOI No. - https://dx.doi.org/10.1021/acsanm.0c02340
Supporting Information - https://pubs.acs.org/doi/suppl/10.1021/acsanm.0c02340/suppl_file/an0c02340_si_001.pdf
I'm quoting the exact part where I'm facing some problems-
Figure 2 shows the stress-calculated strain curves of graphene under uniaxial and biaxial strains. Herein, nominal strain and stress are used, which are defined as the length change divided by the original length and the tensile force divided by the original area of cross-section, respectively (nominal thickness of 3.4 Å is adopted).
Figure 2a shows that the mechanical responses of nanoporous graphene stretched along the armchair direction become distinct from that along the zigzag direction with the increasing strain, resulting from the strain-induced symmetry breaking. The strain to failure of this nanoporous graphene loaded along with the armchair and zigzag directions are 11 and 17%, respectively, which defines the maximum strains that can be applied to the structure. In addition to uniaxial strain, we also investigate the elastic responses of biaxial strain and the strain to failure can also exceed 10% (Figure 2b). Considering the structural stability based on these investigations, we explore the gas separation performance of nanoporous graphene under uniaxial and biaxial strains below 10%.
However, I understand that this is a Stress vs Strain graph. But I have some doubts regarding this -
- What they mean by uniaxial and diaxial strain
- What exactly they mean by armchair direction and zigzag direction
- Lastly, it'll be very helpful for me if one can explain the graph clearly (I'm getting a vague understanding about that)