Highly transparent, stretchable, and self‐healing polymers crosslinked by dynamic zinc(II)-poly(amic acid) bonds

A novel but simple design is presented of a multi-ion network with polyamic acid that combines high extensibility and toughness with spontaneous healing ability. Taking advantage of the carboxylate structure of polyamic acid, the introduction of a sufficient number of metal ions to neutralize the carboxylated groups can form reversible ionic bonds within the polymeric network. Dry-solid zinc(II)-poly(amic acid-PDMS) is transparent and exhibits good mechanical properties, including good ultimate strength (~0.267 MPa) and high stretchability (~360%). In addition, this dynamic network can self-heal at ambient temperature without requiring stimulation from heat, a plasticizer, or a solvent. The very simple method of our proposed polyamic acid polymers opens up the possibility of increasingly utilizing high-performance, low-cost, and environmentally friendly polyamic acids instead of polyimides.