Polyamide Epichlorohydrin‐Sodium Benzenesulfonate Form Curable Coacervate via Synergistic Supramolecular Interactions

ABSTRACT Complex coacervates formed between oppositely charged polyelectrolytes play important roles in encapsulation, micelles, adhesives and coatings. By contrast, coacervates between a polyelectrolyte and small molecules are hard‐to‐form, and the underlying mechanism remains elusive. Here, a cationic polyelectrolyte polyamidoamine epichlorohydrin (PAE) was explored to form a coacervate with a small molecule (i.e., sodium 4‐hydroxybenzene sulfonate, 4‐HBSNa). Effects of temperature and pH on the coacervation were studied, which reveal that the formation mechanism of coacervates is due to synergistic hydrogen bonding and electrostatic interactions. Meanwhile, the PAE/4‐HBSNa coacervate could further undergo gelation due to the ring‐opening reactions between PAE chains to form self‐crosslinked network structures. This study presents a new approach to prepare coacervates via “polyelectrolyte~small molecule” interactions.