Adsorption behaviour of NaCl solution on the surface of MgO: a molecular dynamics study

Magnesium alloy is one of the most promising biomaterials in vascular clogging and bone injury. But it still has some defects to overcome and the key task is to control the degradation velocity. In this study, the reaction between NaCl solution and MgO is simplified as the first stage of the degradation of magnesium alloy stent, and the adsorption properties of NaCl solution on the MgO surface are investigated by MD simulation. The distribution of each component of the solution perpendicular to the MgO surface is analysed and the diffusion coefficient is calculated. Besides, a parameterised analysis is carried out. The results show that there is a solution layer formed at the surface of the MgO, and the existence of metal oxide restricts the diffusion of the solution. The adsorption capacity and the diffuse rate have an opposite variation tendency with the change of temperature, concentration and velocity. The self-diffusion coefficient of the solution increases with the increase in temperature as well as velocity, inversely adsorption capacity decreases with the increase in velocity. Besides, the influence of temperature on the adsorption capacity is small. What is more, the diffusion coefficient decreases while the adsorption capacity increases with the increase in concentration.