Magnetically-Programmed Instability-Driven Pattern Transformations in Soft Materials

A class of transformable materials is introduced with magnetic defect-defined switchable configurations. The soft material can be magnetically-programmed to transform into various encoded patterns utilizing the rich interplay of magnetic interactions and instability phenomenon. The strategy allows us to break the limit of admissible configurations of the instability-induced patterns that dictate the post-transformation behavior. The phenomenon is experimentally realized in a material system consisting of periodically distributed magnetic inclusions in a soft matrix. The programmable magnetic interactions between the inclusions act as smart defects redirecting the material transformations to targeted geometric configurations. Moreover, the role of magnetic spacing and field strength is systematically investigated to map the transition between mechanically-dominant and magnetics-dominant instability patterns. Lastly, the idea of reconfigurable material design is showcased by embedding binary information in magnetic form, which can be read out through the unique repositioning of inclusions via the applied mechanical deformation.