We use Langevin dynamics simulations to study the mass diffusion problem across two adjacent porous layers of different transport properties. At the interface between the layers, we impose the Kedem–Katchalsky (KK) interfacial boundary condition that is well suited in a general situation. A detailed algorithm for the implementation of the KK interfacial condition in the Langevin dynamics framework is presented. As a case study, we consider a two-layer diffusion model of a drug-eluting stent. The simulation results are compared with those obtained from the solution of the corresponding continuum diffusion equation, and an excellent agreement is shown.

我们使用Langevin动力学模拟来研究跨具有不同传输特性的两个相邻多孔层的质量扩散问题。在各层之间的界面处，我们强加了Kedem-Katchalsky（KK）界面边界条件，该条件非常适合一般情况。提出了在Langevin动力学框架中实现KK界面条件的详细算法。作为案例研究，我们考虑药物洗脱支架的两层扩散模型。将模拟结果与从相应的连续扩散方程的解中获得的结果进行比较，并显示出极好的一致性。