Simple and facile synthesis of water-soluble poly(phosphazenium) polymer electrolytes

Water-soluble polymer electrolytes are important industrial materials used as absorbents, rheology modifiers, network formers, and colloidal stabilizers and destabilizers. Herein, the synthesis and alkaline stability of a new class of water-soluble polymer poly(phosphazenium) electrolytes is reported. The charge on the poly(phosphazenium) structure was controlled by the amount of methylating agent used and the resultant electrolytes were water-soluble with a relatively small amount of charge per polymer chain (one charged group per 10 repeat units). Despite phosphazenium salts having excellent alkaline stability, the poly(phosphazenium) polymers with N-methylcyclohexyamino substituents degraded rapidly in alkaline solutions at 60°C. Two-dimensional NMR was used to characterize the poly(phosphazenium) polymer electrolytes and their hydroxide ion induced degradation products.