Study of interfacial adhesion in P(MMA/nBA) copolymer-steel connections based on molecular dynamics simulations

In this article, molecular dynamics (MD) simulation is used to establish the atomistic models of poly(methyl methacrylate)/n-butyl acrylate [P(MMA/nBA)] copolymer with different molar ratios. This P(MMA/nBA) coating is being considered for use as a waterproof adhesive layer on a steel bridge deck. MD simulations were performed to investigate the mechanical, thermodynamic, waterproofing, and interface adhesion properties of the P(MMA/nBA) copolymer. The interface adhesion properties were quantitatively analyzed by calculating the interaction energy of the copolymer-steel interface. The results show that 50/50 P(MMA/nBA) has good flexibility, sufficient shear resistance and better waterproofing properties in comparison to other proportioning schemes. The improvement in the performance of the copolymer is attributed to interchain van der Waals (vdW) interactions forming interdigitation chain morphologies. Besides, the adhesion between the copolymer and a steel surface is primarily dependent on the molar ratio of the polymer under both dry and saturated conditions, and vdW force played an essential role in interfacial adhesive properties. The purpose of this work is to predict the adhesion properties between steel and P(MMA/nBA) acrylate copolymers at an atomistic scale and provide guidance and material reference for researchers to design and develop new waterproofing coatings.