The effective reduction of graphene oxide films using RF oxygen plasma treatment

Abstract

Graphene Oxide (GO) has attracted strong research interest due to its unique mechanical, thermal, electrical, and magnetic properties. Herein, a simple oxygen plasma process is used as an eco-friendly, novel and effective surface treatment technique to enhance the microstructure, adhesion force, and electrical properties of the GO films. GO films were treated in a plasma oxygen environment at a constant RF power of 300 W and different processing times ranging from 0 to 7 min. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy are utilized to examine changes in the type of surface groups and the distribution of bonds energy before and after plasma treatment. Additionally, the effect of RF oxygen plasma treatment on other properties, such as thermal stability, surface roughness, contact angle, work of adhesion, wettability, electrical conductivity, and sheet resistance has been studied. XPS data revealed that RF oxygen plasma treatment reduced the amount of oxygen-containing groups (such as epoxides (O–CO), carbonyls (C–O–C), and carboxyl's (O–CO) from 48.8% for the as-prepared GO film to 33.56% after 5 min of treatment. In addition, the average surface roughness (Ra) increased from ~7.8 of as-prepared GO film to ~8.7 μm, while the work of adhesion improved to reach 134.84 mN/m. However, with increasing plasma processing time up to 7 min, the thermogravimetric analysis (TGA) of the treated GO film showed a weight loss difference of 51.66%. Furthermore, introducing a high amount of CO bonds (carbonyl and SP2 groups of carbon atoms) after plasma treatment improved the electrical conductivity to a value of 0.156 S/m. The current results indicate that the properties of GO can be tuned by varying the degree of oxidation, which may pave the way for new developments in GO-based applications.