Fig. 1: Fabrication and characterization of PI-COOH and RCPIs.

a Schematic illustration of the principle of ligand exchange and recycling based on inorganic CTOC and organic carboxylic acid, where the “rising arrow” represents both the volatilization and removal of pivalic acid. b The chemical structure of the linear PI-COOH containing -COOH group. c Illustration of the crosslinking between CTOC and PI-COOH with the removal of pivalic acid and the recycling process by adding pivalic acid. The photographs present the reversible conversion between solution and gel.