Molecular dynamics simulation on adsorption and diffusion studies at the epoxy resin binder (ERB)-Calcite Interface

In this study, we constructed various ERB-Calcite interfacial models using molecular dynamics simulations to investigate the adsorption and diffusion behaviors. Changes in molecular structural, bond energies, DACF power spectra, FTIR peaks, and the distribution of active group bond angles were observed at the interface. Both physical and chemical adsorption occur at the ERB-Calcite interface, with physical adsorption as the predominant mechanism. The anisotropic,molecularly polarized Calcite surface, along with the molecular components and polarity of ERB, influence interfacial adsorption. In the DGEBA/PPGDGE/TMPMP-Calcite {1 0 4} interface model, the diffusion coefficients of the components follow the order PPGDGE > TMPMP > DGEBA. In contrast, at the ERB-Calcite {1 0 4} interface, ERB molecules must overcome not only interactions with the Calcite surface but also intermolecular constraints within the ERB system. The diffusion thicknesses of ERB, DGEBA, PPGDGE, and TMPMP at the Calcite {1 0 4} surface are 9.33 & Aring;, 9.32 & Aring;, 9.58 & Aring;, and 9.97 & Aring;, respectively. Adsorption and diffusion behaviors coexist and interact at the interface. When ERB molecules are strongly adsorbed onto the Calcite surface, their movement is restricted, leading to a significant reduction in diffusion rate. However, when adsorption is weaker, ERB molecules diffuse more uniformly across the interface. This study provides a theoretical foundation for understanding ERB behavior on mineral interfaces and its potential applications.