Reduced graphene oxide (rGO) is considered better than graphene oxide (GO) for coatings due to the following reasons:
1. Enhanced Conductivity
Graphene Oxide (GO): Contains oxygen-containing functional groups (epoxides, hydroxyls, carboxyls) that disrupt the π-conjugation of graphene, significantly reducing its electrical conductivity.
Reduced Graphene Oxide (rGO): After reduction, most of these oxygen groups are removed, restoring the π-conjugation and improving electrical conductivity. This is beneficial for applications like anti-static coatings or electromagnetic interference (EMI) shielding.
2. Improved Mechanical Properties
GO: The presence of oxygen groups makes it more brittle and less mechanically robust.
rGO: Reduction enhances the mechanical properties, making rGO coatings more flexible, durable, and resistant to mechanical stresses. This makes rGO coatings superior for protective applications where strength and flexibility are key.
3. Increased Hydrophobicity
GO: Hydrophilic due to the oxygen functional groups, which can attract water molecules.
rGO: After reduction, rGO becomes more hydrophobic (water-repellent). This property is highly desirable in coatings for water resistance and anti-corrosion.
4. Better Chemical Stability
GO: Prone to oxidation and can degrade in harsh chemical environments.
rGO: Exhibits greater chemical stability due to the reduction of oxygen groups, making it more resistant to degradation in various chemical environments. This ensures longer-lasting coatings in extreme conditions.
5. Enhanced Thermal Stability
GO: Less thermally stable because of the presence of oxygen groups that can decompose at higher temperatures.
rGO: Improved thermal stability, which is beneficial for coatings exposed to high temperatures, such as in automotive or aerospace applications.
6. Smoother Surface Finish
GO: Rougher surface due to the uneven distribution of oxygen functional groups.
rGO: Smoother surface with fewer defects, providing a more uniform and aesthetically pleasing finish. This is particularly important for coatings in industries where appearance matters, such as automotive finishes.
Conclusion
Reduced graphene oxide (rGO) offers superior conductivity, mechanical strength, hydrophobicity, chemical, and thermal stability compared to graphene oxide (GO), making it a better choice for coating applications that require these enhanced properties.