Dual dynamic helical poly(disulfide)s with conformational adaptivity and configurational recyclability.

The structural dynamics of biopolymers, such as proteins and DNA, feature the unique combination of simultaneous conformational adaptivity and configurational reversibility. However, it remains challenging to design a synthetic system featuring dynamic covalent bonds with secondary structural folding and full recycling capabilities. Here we present a synthetic covalent polymer, constructed from biologically relevant units (amino acids and disulfides), that can reversibly adapt between disordered and helical conformations and can recycle itself to the original small molecules. This dual dynamic feature arises from the subtle synergy of noncovalent bonds (H bonds) and dynamic covalent bonds within a coupled chemical equilibrium, of which thermodynamics is found to follow a nonlinear van't Hoff equation with nonzero heat capacity change. The covalent polymers show conformational dynamics between structured helices and disordered coils and the ability to convert back to the original monomers. This system demonstrates how dual dynamic function can control helical and recyclable polymer formation.