Whereas the separation by surface affinity represents an advanced technique for the separation of nanoparticles with distinct surface properties, how the interaction of particles with nanochannel impacts the separation performance is less understood. Herein, the dynamical density functional theory is employed to study the separation of two types of similar-sized particles with different surface affinities within nanochannels. We show that a proper design of the channel inner-surface, which attracts one type of particles while repelling the other, can promote the permeability and selectivity of particles. Meanwhile, the trade-off relations between permeability and selectivity are found and analyzed in nanochannels of different sizes. Based on dynamical density functional theory calculations, an extended model relating permeability to the equilibrium partition coefficient is proposed to analyze the permeability and selectivity, which displays good predictions of the transport of charged particles in comparison with experimental results. This work provides helpful insights for designing an efficient affinity-based separation of nanoparticles process through nanochannels.

中文翻译：

---

通过纳米通道进行基于亲和力的纳米颗粒分离的渗透性和选择性分析

虽然通过表面亲和性分离代表了一种用于分离具有不同表面特性的纳米颗粒的先进技术，但颗粒与纳米通道的相互作用如何影响分离性能却鲜为人知。在此，动态密度泛函理论用于研究纳米通道内具有不同表面亲和力的两种尺寸相似的颗粒的分离。我们表明，通道内表面的适当设计可以吸引一种颗粒同时排斥另一种颗粒，可以提高颗粒的渗透性和选择性。同时，在不同尺寸的纳米通道中发现并分析了渗透性和选择性之间的权衡关系。基于动态密度泛函理论计算，提出了渗透率与平衡分配系数相关的扩展模型来分析渗透率和选择性，与实验结果相比，该模型显示了对带电粒子传输的良好预测。这项工作为通过纳米通道设计基于亲和力的高效纳米颗粒分离过程提供了有益的见解。