Intermolecular Surface‐To‐Surface Hydrogen‐Bonding Interactions Between Single‐Chain Polymer Nanoparticles

Intramolecular collapse causes a reduction in chain–chain interactions, affecting the material's viscosity in solution and mechanical properties in bulk. Herein, we study the effect of introducing meaningful complementary hydrogen‐bonding sites on the surface of linear and collapsed polymers (single‐chain nanoparticles) in solution. Statistically significant increase in viscosity values is measured when the rheological behavior of complementary polymer blend solutions is compared to solutions of nanoparticles with non‐complementary groups, highlighting the significance of such interactions even in good solvents. Moreover, our results show that such changes in viscosity are more substantial in intermolecularly collapsed chains. These results imply not only the formation of complementary hydrogen‐bonding interactions between the polymer chains but also indicate that the collapsed morphology enhances the non‐covalent interactions between particles, perhaps replacing the lost chain–chain interactions.