An atomic-level investigation into the barrier properties of C3N5-modified epoxy composite coatings for concrete structures
摘要
Nanomaterial-modified epoxy coatings are considered an effective method for protecting concrete. Molecular dynamics (MD) simulations were used to study the effect of C3N5 and its derivative C3N5-OH on the properties of epoxy coating, as well as the interfacial properties between epoxy coating and concrete. Three MD models were established and their properties were investigated in both dry and sodium chloride solution. Results indicate that doping the epoxy coating with C3N5 and C3N5-OH reduces its free volume. The strength increases from 0.42 GPa to 0.70 GPa and 0.76 GPa after doping with C3N5 and C3N5-OH, respectively. Similarly, the elastic modulus increases from 3.09 GPa to 4.26 GPa and 4.95 GPa, respectively. The addition of C3N5 and C3N5-OH increases the interaction energy of epoxy from 99.3 kcal/mol to 132.2 kcal/mol and 167.2 kcal/mol, respectively. Correspondingly, the adsorption distance decreases. The doping of C3N5 effectively inhibits the diffusion of sodium chloride solution, mitigating its impact on the properties of the epoxy/concrete interface. This study demonstrates that C3N5-modified epoxy coatings are a promising solution for extending the service life of concrete structures.
MethodsThe initial molecular model construction, cross-linked network generation, and the addition of NaCl solution were all completed using the Materials Studio software. MD simulations were conducted using LAMMPS software. The CVFF force field was selected for the epoxy resin composite layer, while the ClayFF force field was used for the CSH matrix.