Simple systematic synthesis of size-tunable covalent organophosphonitridic framework nano- and microspheres

Covalent organophosphonitridic framework nano- and microspheres were synthesized by a condensation reaction between hexachlorocyclotriphosphazene (PNC) and 3,3'-diaminobenzidine (DAB) in anhydrous dimethylformamide (DMF) at a temperature of 125 degrees C in the presence of polyvinyl pyrrolidone (PVP). The spheres were almost monodisperse and the diameter could be adjusted from 80 nm to 1.5 mu m by varying the concentration of the reactants PNC and DAB. The spheres are thermally stable up to 480 degrees C in air and are completely oxidatively- depolymerized at 750 degrees C.