Emergent mechanical properties of self-assembled polymeric capsules

Synthetic self-assembled systems combine responsiveness and reversibility w ith the ability to perform chemical tasks such as molecular recognition and catalysis. An unmet challenge is the construction of polymeric materials t hat, like nature's tubulin. are simultaneously reversible and capable of us eful physical tasks. We report here a class of reversibly formed polymers t hat show covalent-polymer mechanical integrity in solution and in the solid state. Non-Newtonian. polymeric behavior is observed despite the low molec ular weight of the individual subunits and the seemingly weak forces holdin g the assemblies together. These polymers assemble through self-complementa ry hydrogen bonding and by physical encapsulation of small molecules; accor dingly, the emergent macroscopic structure and function can be controlled b y appropriate chemical signals.