Programmable mechanical metastructures modeling polydomain materials

The orientation and distribution of microscopic units in polydomain materials contribute to their functionality and performance. However, within bulk materials from traditional synthesis and modeling, achieving flexible and precise arrangements of the microscopic units is challenging, which restricts the capabilities to fully understand and manipulate their polydomain-based properties. Here, we present a metastructure to mimic both mesoscale phase change and macroscopic mechanical properties of polydomain materials such as liquid crystal elastomers, which achieves unprecedented tunability over domain structures through the rational design of unit cells and their spatial arrangements. These metastructure system is used to explore and directly visualize the complex mesoscale topological deformation mechanisms hidden at molecular scales, providing fundamental insights into the mechanical properties of these materials. Beyond mimicking known polydomain materials, we demonstrate functionalities including mechanical encoding/decoding and programmable shape morphing. Our results establish a framework for understanding and designing topology-tunable functional polydomain materials.