Growth rules for irregular architected materials with programmable properties

• Published in: Science (American Association for the Advancement of Science) Vol. 377; no. 6609; pp. 975 - 981
• Main Authors: Liu, Ke, Sun, Rachel, Daraio, Chiara
• Format: Journal Article
• Language: English
• Published: Washington The American Association for the Advancement of Science 26.08.2022
• DOI: 10.1126/science.abn1459
• ISSN: 0036-8075; 1095-9203

Biomaterials display microstructures that are geometrically irregular and functionally efficient. Understanding the role of irregularity in determining material properties offers a new path to engineer materials with superior functionalities, such as imperfection insensitivity, enhanced impact absorption, and stress redirection. We uncover fundamental, probabilistic structure–property relationships using a growth-inspired program that evokes the formation of stochastic architectures in natural systems. This virtual growth program imposes a set of local rules on a limited number of basic elements. It generates materials that exhibit a large variation in functional properties starting from very limited initial resources, which echoes the diversity of biological systems. We identify basic rules to control mechanical properties by independently varying the microstructure’s topology and geometry in a general, graph-based representation of irregular materials. Materials with irregular microstructures are common in the natural world and often have interesting properties. Liu et al . devised a growth-inspired program for generating irregular materials from a limited number of basic elements. Using building blocks with arbitrary complexity, the authors stochastically connected them subject to a set of local rules. The results echoed the diversity of natural systems with a large range of functional properties. —BG A strategy for developing irregular materials can lead to a wide range of functional properties.