Self-Healable Functional Polyacrylates Using Dual Click Chemistry; Electrophilic-Substitution and Boronic Ester Exchange Reactions.

In this work, a self-healable functional acrylate terpolymer with dual dynamic networks of supramolecular H-bonds and dynamic covalent boronic ester bonds was prepared. The functional terpolymer was synthesized via thermally initiated reversible addition-fragmentation chain transfer (RAFT) polymerization of n-butyl acrylate (BA), furfuryl methacrylate (FMA), and glycerol monomethacrylate (GMMA). The furfuryl group of FMA reacts with 4-phenyl-3H-1,2,4-triazole-3,5 (4H)-dione (PTAD) via electrophilic substitution (ES)-click reaction, resulting in the formation of supramolecular H-bonded networks, whereas the diol functionality of the GMMA unit reacts with 1,4-phenylenediboronic acid (PDBA) to incorporate dynamic boronic ester networks into the functional terpolymer. These reactions are rapid and reversible in nature, and the formation of these dynamic networks can occur either individually or in a synergistic combination within a few minutes (2 min) under ambient conditions. The cross-linked terpolymer also exhibited remarkable self-healing and reprocessing characteristics owing to the reversible nature of these dynamic networks, as demonstrated by the restoration of the scratched surface upon exposure to heat, and measured quantitatively via tensile measurements.