Graphite oxide platelets functionalized by poly(ionic liquid) brushes and their chemical reduction

Abstract

In this paper, graphite oxide (GO) platelets functionalized by poly(ionic liquid) brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The chemical reduction of these functionalized platelets was also investigated. The functionalized platelets and their reduced products were characterized and confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, ζ potential measurements, four-probe electrical measurements, and high-resolution transmission electron microscopy. Results demonstrated that the poly(ionic liquid) brushes could be grafted from the GO surface by SI-ATRP. The surface charges of the GO platelets surface transformed from negative to positive. Upon reduction by hydrazine, the functionalized platelets were partially reduced, as suggested by the observation that reduced GO exhibits electrical conductivity three magnitudes higher than that of original GO. Although partially reduced GO platelets were not as conductive as reduced GO without functionalization, they can be homogenously dispersed in water due to the presence of poly(ionic liquids) brushes.