From Physical Network to Network Materials

Materials are inherently network-based systems, whose physical properties are defined by the structure of the chemical bonds that connect their atoms or molecules. Network science has revealed a rich diversity of network architectures across biological, social, and technological systems. However, these advances have had limited impact on materials science, mainly because atomic bonds impose strict constraints on network structures, limiting materials to specific, relatively simple network configurations. However, additive manufacturing allows us to print structures of arbitrary geometry, raising the question: if we can create materials with arbitrary network structures, what network configurations have the most desirable material properties?

Our research is driven by the insight that the physical properties of most materials, including advanced metamaterials, are constrained by their reliance on single-scale characteristics across essential attributes like constant or unimodal coordination number (degree), bond length, and bond strength. Our work is also inspired by recent advances in our understanding of physical networks—from the brain connectome to vascular networks—that show a high geometric and structural diversity [1-4]. Hence, here we focus on the mechanical and transport properties of materials that break from the single-scale paradigm across one or more foundational network properties. We explore the scaling features of these materials, and, working with experimental collaborators, we study their mechanical and thermal properties.

[1] Dehmamy, Milanlouei, & Barabási, A structural transition in physical networks. Nature 563, 676–680 (2018).

[2] Liu, Dehmamy, & Barabási. Isotopy and energy of physical networks. Nat. Phys. 17, 216–222 (2021).

[3] Posfai et al, Impact of physicality on network structure. Nat. Phys. 20,142–149 (2024).

[4] Glover, Barabási, Measuring Entanglement in Physical Networks. Phys. Rev. Lett. 133, 077401 (2024)