Ionic Diffusoosmosis in Nanochannels Grafted with End-Charged Polyelectrolyte Brushes.

Ionic Diffusoosmosis in Nanochannels Grafted with End-Charged Polyelectrolyte Brushes.
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DOI：
10.1021/acs.jpcb.8b04827
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发表时间：
2018-07
期刊：
The journal of physical chemistry. B
影响因子：
--
通讯作者：
R. Maheedhara;H. S. Sachar;Haoyuan Jing;Siddhartha Das
R. Maheedhara;H. S. Sachar;Haoyuan Jing;Siddhartha Das
中科院分区：
其他
文献类型：
--
作者：
R. Maheedhara;H. S. Sachar;Haoyuan Jing;Siddhartha Das

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在本文中，我们发展了一个理论来研究施加轴向盐浓度梯度驱动的离子扩散渗透（IDO）在软纳米通道或纳米通道接枝与端部带电的聚乙烯（PE）刷。我们的分析首先量化的扩散诱导电场，这主要是由所施加的浓度梯度（CG）与诱导渗透的贡献很小。该感应电场触发电渗（EOS）运输，而净扩散渗透（DOS）运输由该EOS运输和化学渗透（COS）运输的组合产生，所述化学渗透（COS）运输由所施加的CG感应的压力梯度引起。我们的研究结果表明，DOS运输是大规模增强的纳米通道接枝PE刷与弱接枝密度源于显着增强EOS运输所造成的EOS体力远离纳米通道壁的本地化。对于COS传输辅助EOS传输的情况，这种增强甚至更强。另一方面，由于刷诱导的额外阻力的严重性，DOS输运得到严重降低在接枝有致密PE刷的纳米通道。我们预计，这些发现将有助于解开一个全新的理解诱导电动运输在软纳米通道。
In this paper, we develop a theory to study the imposed axial salt-concentration-gradient-driven ionic diffusioosmosis (IDO) in soft nanochannels or nanochannels grafted with end-charged polyelectrolyte (PE) brushes. Our analysis first quantifies the diffusioosmotically induced electric field, which is primarily dictated by the imposed concentration gradient (CG) with little contribution of the induced osmosis. This induced electric field triggers an electroosmotic (EOS) transport, while the net diffusioosmotic (DOS) transport results from a combination of this EOS transport and a chemiosmotic (COS) transport arising from the pressure gradient induced by the applied CG. Our results demonstrate that the DOS transport is massively enhanced in nanochannels grafted with PE brushes with weak grafting density stemming from the significantly enhanced EOS transport caused by the localization of the EOS body force away from the nanochannel walls. This augmentation is even stronger for cases where the COS transport aids the EOS transport. On the other hand, the DOS transport gets severely reduced in nanochannels grafted with dense PE brushes owing to the severity of the brush-induced additional drag force. We anticipate that these findings will help to unravel an entirely new understanding of induced electrokinetic transport in soft nanochannels.