Noncovalent Synthesis of Amphiphilic Block Copolymers Through Host-Guest Interactions

A supramolecular approach for constructing amphiphilic block copolymers has been developed based on host-guest interactions between calix[5]arene-functionalized polyethylene glycol (PEG) and [60]fullerene-functionalized polystyrene (PS). Supramolecular amphiphilic polymers were formed via spontaneous assembly in solution, as confirmed by UV/vis titration and DOSY NMR spectroscopy. Drop casting of a mixture of host- and guest-appended polymers onto substrates yielded smooth, continuous films. Atomic force microscopy (AFM) revealed, in addition to the smooth topographies, an alternating modulation in mechanical stiffness, which was ascribed to the interspersed PEG- and PS-rich regions. Differential scanning calorimetry (DSC) revealed transitions derived from the PEG and PS chains for a mixture of host- and guest-appended polymers, suggesting the coexistence of the PEG- and PS-rich regions. These results suggest that host-guest interactions successfully couple hydrophilic and hydrophobic polymer chains, suppressing macroscopic phase separation and yielding films with nanoscale mechanical heterogeneity. This strategy offers a modular and efficient platform for the fabrication of supramolecular amphiphilic block copolymers with tunable nanostructures.