Bioinspired cross-linking of preceramic polymers via metal ion coordination bonding

Metal coordination chemistry is common in biology, with many proteins containing metal ion-based structural motifs or catalytic centers. An interesting example of nature's use of coordinate bonding to create a proteinaceous structural material is found in the Alitta virens marine worm jaw. Inspired by Zn+2 cross-linked polymers in A. virens, we have extended coordination cross-linking to preceramic polymers. Commercially available Si-based backbones functionalized with pyridyl-moieties were introduced to metal ions to initiate cross-linking. Metal coordination offered a single knob to tune multiple characteristics of the material before and after pyrolysis. The loading of the metal ions into the polymer impacted the viscoelastic properties, thermal stability, and ceramic yield. Pyrolysis yielded a ceramic representative of the metal ion cross-linker (e.g., forming TiC/SiC nanocomposites).