Adsorption Mechanisms in Polymer–Ceramic Interfaces: DFT Investigation

Abstract

A fundamental DFT-based mechanistic study is presented for the adsorption of a polymer (cured epoxy-amine system) onto a ceramic (dry and hydroxylated alumina) surface. Despite decades of research, the nature and contributions of intermolecular forces governing the adsorption mechanism between a polymer and a ceramic surface are yet to be completely understood, which this study focuses upon. Both dry and hydroxylated alumina surfaces have been considered for the adsorption of secondary and tertiary epoxy amines. In addition to highlighting the roles of the O–Al and N–Al bonds, this study specifically elucidates the role of the N atom in cured epoxy-amine polymeric systems in the adsorption mechanism. Hydrogen bonds such as OH···N play a vital role in polymer adsorption for hydroxylated ceramic surfaces, which demonstrate higher adsorption energies compared to dry surfaces. Steric hindrances are observed for tertiary epoxy-amine polymeric systems, lowering the adsorption energies compared with secondary epoxy-amine systems. The theoretical research demonstrates the vital role of intermolecular noncovalent interactions in defining the adsorption mechanisms between a polymer and ceramic surface, thereby developing a benchmark for future experimental investigations in the domain.