Characterizing the Fundamental Adhesion of Polyimide Monomers on Crystalline and Glassy Silica Surfaces: A Molecular Dynamics Study

Understanding the interaction between polyimide and inorganic surfaces is vital in controlling interfacial adhesion behavior. Here, molecular dynamics simulations are employed to study the adhesion of polyimide on both crystalline and glassy silica surfaces, and the effects of hydroxylation, silica structure, and polyimide chemistry on adhesion are investigated. The results reveal that polyimide monomers have stronger adhesion on hydroxylated surfaces compared to nonhydroxylated surfaces. Also, adhesion of polyimide onto silica glass is stronger compared to the corresponding crystalline surfaces. Finally, we explore the molecular origins of adhesion to understand why some polyimide monomers like Kapton have a stronger adhesion per unit area (adhesion density) than others like BPDA-APB. We find this occurs due to a higher density of oxygen's in the Kapton monomer, which we found to have the highest contribution to adhesion density.