DOUBLE FACED ROMAN GOD JANUS. “The “Janus” term has been extended to describe the “dissymmetrical entities” in general, including macromolecules, supramolecular assemblies, nanoparticles, and colloidal particles. In synthesis, it requires the break of symmetry in the first place to create the “Janus” feature.” Breaking symmetry to induce novel properties.
https://chenggroup.uakron.edu/files/2015/05/11-yiwenli-ja202906m.pdf