Constructing Self-Healing Polydimethylsiloxane through Molecular Structure Design and Metal Ion Bonding

Self-healing polydimethylsiloxane (PDMS) has garnered significant attention due to its potential applications across various fields. In this study, a functionalized modification of PDMS containing di-aminos was initially conducted using 2,6-pyridinedicarbonyl chloride to synthesize pyridine-PDMS (Py-PDMS). Subsequently, rare earth metal europium ions (Eu³⁺) were incorporated into Py-PDMS. Due to the coordination interaction between Eu³⁺ and organic ligands, a coordination cross-linking network was created within the Py-PDMS matrix, resulting in the fabrication of Eu³⁺-Py-PDMS elastomer. At a molar ratio of Eu³⁺ to ligands of 1:1, the tensile strength of Eu³⁺-Py-PDMS reached 1.4 MPa, with a fracture elongation of 824%. Due to the dynamic reversibility of coordination bonds, Eu³⁺-Py-PDMS with a metal-to-ligand molar ratio of 1:2 exhibited varying self-healing efficiencies at different temperatures. Notably, after 4 h of repair at 60 °C, its self-healing efficiency reached nearly 100%. Furthermore, the gas barrier properties of Eu³⁺-Py-PDMS with a molar ratio of 1:1 was improved compared with that of Eu³⁺-Py-PDMS with a molar ratio of 1:1. This study provides an effective strategy for the design and fabrication of PDMS with high mechanical strength, high gas barrier properties, and exceptional self-healing efficiency.