Mechanical Properties of Schwarzites: From Atomic Models to 3D Printed Structures

Schwarzites are 3D crystalline porous carbon-based structures [1]. They contain carbon rings with more than 6 atoms producing positive and negative curvature topologies. They can form rigid foam- like structures with unusual mechanical and electronic properties. In this work we have investigated the mechanical properties of some Schwarzite families (primitive and gyroid), from atomic to macro- scales. In particular, we have investigated their mechanical behavior under kinetic impacts and compressive and tensile loadings. We carried out fully atomistic molecular dynamics (MD) simulations using the reactive force field ReaxFF. Our MD results [2,3] show that they exhibit remarkable resilience under mechanical compression. They can be reduced to half of their original size before structural failure (fracture) occurs. From the optimized atomic model we generated high-resolution multi-material 3D printed structures (cm size), which were submitted to compressive and impact tests [2]. Also, MD and 3D printed results reveal a unique layered deformation mechanism. The present approach (translating atomic models into 3D macro-scale ones) is completely general and can be used for other structures. This opens new perspectives to create engineered materials based on atomic-scale structures that remain impossible and/or elusive to synthesize.

[1] A. L. Mackay, H. Terrones, Nature 1991, 352, 762. [2] S. M. Sajadi, P. S. Owuor, S. Schara, C. F. Woellner, V. Rodrigues, R. Vajtai, J. Lou, D. S. Galvao, C. S. Tiwary, and P. M. Ajayan, Adv. Mater. 2017, 1704820. [3] C. F. Woellner, T. Botari, E. Perim, and D. S. Galvao, MRS Adv. 2018, 3, 448.