Formation of a Miscible Supramolecular Polymer Blend through Self-Assembly Mediated by a Quadruply Hydrogen-Bonded Heterocomplex

A supramolecular network polymer consisting of a pair of immiscible polymers, poly(butyl)methacrylate (PBMA) and polystyrene (PS), is described. A urea of guanosine (1, UG) and 2,7-diamido-1,8-naphthyridine (2, DAN), which form an exceptionally strong quadruply hydrogen-bonding complex, are displayed at 1-10 mol % along the main backbone of PBMA and PS, respectively. (1)H NMR studies show heterocomplexation between UG and DAN exclusively. This high-fidelity, high-affinity supramolecular connection of two different polymer coils at the molecular level produces a polymer blend. Blends containing different weight ratios of the polymers and mole percent of the recognition units were characterized by AFM and DSC experiments with no isolated domains observed and a single glass-transition temperature (T(g)). The T(g) is tunable by varying the weight ratio of the polymers in the blend. In addition, viscosity measurements, size-exclusion chromatography (SEC), and dynamic light-scattering (DLS) studies demonstrate the formation of a supramolecular network structure.