Synthesis of a self-healing siloxane-based elastomer cross-linked via a furan-modified polyhedral oligomeric silsesquioxane: investigation of a thermally reversible silicon-based cross-link
We have successfully prepared an elastomeric material exhibiting excellent temperature-controlled self-healing characteristics. A synthetic procedure is provided to graft siloxane chains with maleimidocarboxyphenyl functional groups. A furan-modified polyhedral oligomeric silsesquioxane with flexible tethers was also synthesized to cross-link the siloxane chains via a Diels–Alder reaction. A model system was prepared to study the thermally reversible nature of the cross-linked entities using differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) experiments. Likewise, dynamic solid-state 1H NMR experiments confirmed the reversibility of the linkages in the polymeric materials. Elastomers that were completely severed could be reannealed to the point that signs of a defect were imperceptible even by scanning electron microscopy (SEM).