A molecular dynamics study on the role of oxygen-containing functional groups on the adhesion of polymeric films to the aluminum surface

Polymers with carbonyl groups are widely used in metal binding. It is believed that oxygen-containing functional groups have an essential role in the adhesion of polymers to metal surfaces. Here, molecular dynamics simulation has been employed to study oxygen atoms in the vinyl acetate and maleic acid functional groups that have a main role in the adhesion of poly (vinyl chloride-co-vinyl acetate-co-maleic acid) lacquer to aluminum. Based on the results, carbonyl groups had various neighboring bonds that resulted in different positioning and performances of oxygen atoms in the bonding strength. While oxygen atoms of carbonyl bonds in vinyl acetate had a higher tendency for the aluminum surface, oxygen atoms of maleic acid were closer to the aluminum surface, due to the smaller special hindrance of neighboring hydrogen atoms. It led to a difference in the surface concentrations of oxygen among different comonomers. Analyzing the orientation function revealed that the carbonyl bonds of vinyl acetate and maleic acid were oriented near the aluminum surface, as had been previously observed by Kim et al. [1]. The bond orientation and distance from the aluminum surface were found to be the main reasons behind the more effective role of maleic acid in the adhesion to aluminum, compared to vinyl acetate.