Addition of complex functionality to surfaces via sulfonyl nitrenes and sufex click reactions

The development of new grafting and attachment chemistries is of high importance in the materials science community. Attaching polymers to chemically inert substrates is of interest in fields such as coatings and composites. This work looks at the functionalization of the highly inert substrate Kevlar using sulfonyl azide containing polymers to generate sulfonyl nitrene groups for aryl C-H insertion. The covalent coating of polymers is demonstrated, as well as the retention of critical mechanical properties. In addition the use of Sulfur(VI) Fluoride Exchange (SuFEx) chemistry in functionalizing polymer brushes is examined. SuFEx is a new form of click chemistry that uses sulfonyl fluorides or fluorosulfates and silyl ethers in the presence of certain bases to form sulfonate or sulfate linkages. It is highly orthogonal to most other described forms of click chemistry, and the precursors are generally redox, thermally, radical, and UV stable. This post-polymerization modification technique provides access to the inclusion of free-radical incompatible moieties in polymer brush in a single step. Using this motif, new pathways for orthogonal functionalization and patterning of polymer brush surfaces should be possible.