Deposition Kinetics of Graphene Oxide on Charged Self-Assembled Monolayers

Numerous applications of graphene oxide (GO) thin films have emerged after the discovery of their intriguing electrical, mechanical, and thermal properties. Function and performance of such GO films tend to depend on their homogeneity, morphology, and nanostructure, which are influenced by their deposition kinetics. This study investigates the kinetics of GO deposition on substrates of systematically varying surface potentials via systematic quartz crystal micro balance with dissipation and atomic force microscopy techniques. While the substrates with a positive surface potential yielded high deposition rates but wrinkled GO films, the substrates with a negative surface potential lead to low deposition rates but smooth GO films. For the repulsive interactions, the deposition rate was found to roughly exponentially decay with the product of surface potentials of GO and the substrate. Also, building upon the Gouy-Chapman theory and the additivity of van der Waals interactions, expressions for electrostatic double-layer and van der Waals interactions between a nanoplatelet (e.g., GO) and a planar wall under parallel, perpendicular, and inclined configurations were derived to explain the observed deposition trends. We anticipate that these findings will provide useful guidelines for manipulating and controlling the aqueous deposition of GO and structural properties of resultant GO films.