The synergistic effects of graphene on the physical, hydrophobic, surface, and thermal properties of acrylic-epoxy-polydimethylsiloxane composite coatings

Acrylic-epoxy based polydimethylsiloxane (PDMS) nanocomposite coatings loaded with different concentrations (0.5-3 wt%) of graphene nanoparticles were successfully prepared via solution intercalation approach. The main objective of this research was to investigate the hydrophobicity and thermal properties of the graphene-based coatings for various applications. Furthermore, the thermal analysis of the coatings was conducted via thermogravimetric analysis (TGA). In addition, the ultraviolet-visible (UV-Vis) spectroscopy and water contact angle (WCA) instrument were employed to evaluate the degree of transparency and surface wettability of the coatings. The surface adhesion analysis of the coatings was conducted using cross-hatch test (CHT) and the dispersion of the graphene nanoparticles was examined via field emission scanning electron microscope (FESEM) respectively. In terms of surface wettability, the graphene coating sample (1 % G) exhibited the highest WCA value of 99.75 degrees, thus revealing its hydrophobic attribute. Moreover, the results obtained from TGA analysis revealed that the incorporation of graphene nanoparticles into the polymer matrix showed a reduction in degradation temperature, in other words, the increment of graphene content resulted the cross-linking density of the coating to decrease. Furthermore, at lower loading rates (e.g., 1 wt%), the FESEM results confirmed the excellent and even distribution of the graphene nanoparticles within the polymer matrix particularly at lower loading rates. At higher loading rates of graphene nanoparticles, the overall performance of the coatings was observed to decrease due to the presence of large agglomeration, which resulted the WCA to slightly decrease. In summary, due to its unique structure and properties, the incorporation of graphene as nanofiller into the polymer matrix could effectively enhance the compactness and protective performance of the acrylic-epoxy surface tolerant coating.