Sulfonation of (Aryloxy)- and (Arylamino)phosphazenes: Small-Molecule Compounds, Polymers, and Surfaces

Sulfonation reactions have been developed that convert aryloxy or arylamino groups linked to phosphazenes to the arylsulfonic acid derivatives. The reactions were developed at three levels-first, with small-molecule phosphazene cyclic trimers; second, with phosphazene high polymers in the solution state; third, at the surfaces of solid polyphosphazenes. The reagents employed included concentrated H₂SO₄, fuming H₂SO₄, and ClSO₃H. Molecular level products were studied by ³¹P, ¹³C, and ¹H NMR spectroscopy, while the surface-reacted materials were examined by XPS, SEM, ATR-IR, contact angle, and optical microscopy. This chemistry is of broad utility for the preparation of hydrophilic and hydrogel surfaces on polymers and for the development of biocompatible or antibacterial materials.