On the mechanical properties and auxetic potential of various organic networked polymers

Joseph N Grima (1) , Daphne Attard (2) , Richard Nicholas Cassar (2) , Luke Farrugia (2) , Lara Trapani (2) , Ruben Gatt (2)

1 Department of Chemistry
2 University of Malta [Malta]

We simulate and analyse three types of 2 D networked polymers which had been predicted to exhibit on-axis auxetic behaviour (negative Poisson's ratio), namely (i) polyphenylacetylene networks which behave like flexing re-entrant honeycombs, commonly referred to as ‘reflexynes', (ii) polyphenylacetylene networks that mimic the behaviour of rotating triangles, commonly referred to as ‘polytriangles' and (iii) networked polymers built from calix[4]arene units. More specifically, we compute and compare their in-plane off-axis mechanical behaviour, in particular their off-axis Poisson's ratios and show that in some cases, the sign and magnitude of Poisson's ratio is dependent on the direction of loading. We propose two functions which can provide a measure for the extent of auxeticity for such anisotropic materials and show that the polytriangles are predicted as the most auxetic when compared to the other networks with the reflexyne re-entrant networks being the least auxetic.

Mots clés: Physical Sciences

Joseph N Grima, Daphne Attard, Richard Nicholas Cassar, Luke Farrugia, Lara Trapani, et al.. On the mechanical properties and auxetic potential of various organic networked polymers. Molecular Simulation, 2008, 34 (10-15), pp.1149-1158. ⟨10.1080/08927020802512187⟩. ⟨hal-00515061⟩