Suppression of electroosmotic flow by polyampholyte brush

• Published in: Microfluidics and nanofluidics Vol. 17; no. 5; pp. 923 - 931
• Main Authors: Zuo, Yuxin, Wang, Guoqiang, Yu, Ying, Zuo, Chuncheng, Liu, Zhichao, Hu, Dongmei, Wang, Yirui
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-11-2014; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Applied fluid mechanics; Biomedical Engineering and Bioengineering; Engineering; Engineering Fluid Dynamics; Exact sciences and technology; Flow profiles; Flow velocity; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Nanotechnology and Microengineering; Physics; Research Paper; Electroosmotic flow; Molecular dynamics; Polyampholyte brush; Suppression; Polyampholyte; Digital simulation; Molecular dynamics method; Nanostructures; Brush; Electroosmosis; Nanochannel; Modelling; Nanofluidics
• ISSN: 1613-4982; 1613-4990
• DOI: 10.1007/s10404-014-1383-1

Molecular dynamics simulations are conducted to investigate the suppression of electroosmotic flow by grafting polyampholyte brushes onto two parallel channel walls. The effects of grafting density and charge distribution of polyampholyte brushes on the electroosmotic flow velocity, salt ion distribution, and conformational characteristics of grafted brushes are studied in detail. Simulation results indicate that increasing the grafting density induces a stronger suppression of electroosmotic flow. The flow velocity is significantly influenced by the different charge distributions of polyampholyte brushes. In addition, an important flow phenomenon we have found is that the flow velocity profile shows a valley at the center of the channel. These results reveal that the flow velocity is dependent not only on the conformation of the polyampholyte brushes but also on the anion and cation distributions. The hierarchical distribution of salt ions is caused by the special properties of polyampholyte brushes.