Li Lujuan, Cao Qianqian, Liu Hao, Gu Zhiqing, Yu Ying, Huang Fengli, Zuo Chuncheng
College of Mechanical and Electrical Engineering, Jiaxing University Jiaxing 314001 P. R. China
RSC Adv. 2019 Nov 28;9(67):38944-38951. doi: 10.1039/c9ra08365k. eCollection 2019 Nov 27.
Using molecular dynamics simulations based on explicit-solvent model, we study migration of polymer-modified nanoparticles through nanochannels coated with polymers. The polymers densely grafted on the spherical nanoparticle and the channel surface form spherical polymer brush (SPB) and planar polymer brush (PPB), respectively. The migration of the neutral polymer-modified nanoparticle is driven by electroosmotic flow (EOF). The effects of the electric field strength and the SPB-PPB interaction on polymer conformations and transport dynamics of the SPB are explored. The migration velocity of the SPB reduces as the interaction between the SPB and the PPB increases. For strong SPB-PPB interaction, the directional migration of the SPB can be triggered only after the electric field strength exceeds a critical value. The high EOF velocity forces the center of mass of the spherical nanoparticle to keep near the central region of the channel due to high shear rate close to the brush-fluid interface. Unlike electrophoresis of charged polymer-grafted spherical particles, the SPB adopts a more extended conformation in the plane perpendicular to the EOF direction.
基于显式溶剂模型，利用分子动力学模拟，我们研究了聚合物修饰的纳米颗粒在聚合物涂层纳米通道中的迁移。紧密接枝在球形纳米颗粒和通道表面的聚合物分别形成球形聚合物刷（SPB）和平面聚合物刷（PPB）。中性聚合物修饰的纳米颗粒的迁移由电渗流（EOF）驱动。研究了电场强度和SPB - PPB相互作用对SPB的聚合物构象和传输动力学的影响。随着SPB与PPB之间相互作用的增加，SPB的迁移速度降低。对于强SPB - PPB相互作用，只有在电场强度超过临界值后才能触发SPB的定向迁移。由于靠近刷 - 流体界面处的高剪切速率，高EOF速度迫使球形纳米颗粒的质心保持在通道的中心区域附近。与带电聚合物接枝球形颗粒的电泳不同，SPB在垂直于EOF方向的平面上采用更伸展的构象。
