Synthesis and Solution Processing of a Hydrogen-Bonded Ladder Polymer

Rigid coplanar ladder polymers equipped with regulated intermolecular interactions promise unique solid-state properties. Efficient synthesis and solution processing of these materials, however, are challenging because of their extremely poor solubility. Herein, we describe a highly efficient, gram-scale synthesis of a hydrogen-bond-containing ladder polymer through an approach free of metal catalyst. The quinacridone-derived repeating unit features multiple self-complementary intermolecular hydrogen bonds along the rigid backbone. Using a reversible hydrogen-bond protection strategy, we were able to fully characterize this insoluble polymer in solution and process it into smooth thin films. In the solid state, the material demonstrated excellent resistance to organic solvents, aqueous acids, and thermal treatments, rendering a solution-processed, solvent-resistant thin film. This unique property allows for solution manipulation of robust polymer materials for applications associated with extreme operating or processing conditions. This scalable fused-ring polymer also demonstrated promising potential as a precursor for graphitic carbon materials.