Intercalation and Exfoliation Compounds of Graphite Oxide with Quaternary Phosphonium Ions

Highly ordered graphite oxide intercalation compounds (GOIC) and fully disordered graphite oxide exfoliated compounds (GOEC) have been obtained, for two quaternary phosphonium salts. X-ray diffraction patterns of both GOIC and GOEC maintain the 100 and 110 reflections of GO, clearly indicating the maintenance of in-plane GO order. For GOICs, few 00 l reflections (with l up to 3) appear, indicating an increase with respect to GO of crystalline order as well as an increase of spacing between GO layers from 0.84 nm up to 1.40 nm. GOIC and GOEC have been compared for their kinetics of release in aqueous solutions of a phosphonium ion, being a known antibacterial agent. GOICs exhibit pH sensitive cation release, with zero order kinetics, which could be helpful for applications requiring triggered and constant supply of active ions.