Tunable Ionic Transport for a Triangular Nanochannel in a Polymeric Nanofluidic System

Abstract

Recently, tremendous engineering applications utilizing new physics of nanoscale electrokinetics have been reported and their basic fundamentals are actively researched. In this work, we first report a simple and economic but reliable nanochannel fabrication technique, leading to a heterogeneously charged triangular nanochannel. The nanochannel utilized the elasticity of PDMS when it bonded with a micrometer-scale structure on a substrate. Second, we successfully demonstrated novel ionic transportations by tweaking the micrometer structures: (1) the transition of nonlinear ionic conductance depending on the nanochannel properties and (2) the ionic field-effect transistor. Nanochannel conductance has two distinguishable nonlinear regimes called the "surface-charge-governed" and the "geometry-governed" regime and its only individual overlooks were frequently reported. However, the transition between two regimes by adjusting nanochannel properties has not been reported due to the difficulty of functional nanochannel fabrication. In addition, a gate voltage was comfortably applied to the triangular nanochannel so that the field-effect ion transportation was reliably achieved. Therefore, presenting triangular nanochannels have critical advantages over its heterogeneous and tunable surface properties and thus, could be an effective means as an active fundamental to control and manipulate the ion-electromigration through a nanofluidic system.

Effect of geometry on concentration polarization in realistic heterogeneous permselective systems

“…The theoretical framework provided in this work for a 3D and 3-layers systems can be expanded upon to account for additional effects, e.g. asymmetric bulk concentrations [21,22], non-straight nanochannel/nanopore geometries [32], or even asymmetric entrances of a straight permselective medium [14]. …”

“…1). Solving for a 3 layer system versus the commonly solved 1 layer system, consisting solely of the depleted layer [3,11,19,25,26], will better facilitate the comparison of theoretical models to experiments [5,6,12,13,[27][28][29][30][31][32][33] and simulations [34][35][36][37].…”

“…Such a geometry realistically describes systems that have been the subject of numerous recent experimental and numerical works [6,11,12,15,21,[27][28][29][30][31][32][34][35][36][37]41,42]. Additionally, this geometry can also describe a periodic array of permselective regions (e.g.…”

Electrokinetics in a Nanochannel

“…The major function of a nanofluidic system is active ion control by using an external electric field; thus, a study of fundamental ion transport through a nanoporous junction would be useful. [1] 담수/정수 장치, [2] 액상 반도체 [3] 등의 새로운 공 학적 응용물이 출현하게 되었습니다. 우, 전해질 농도와 전기전도도는 비선형적인 관계를 보입니다.…”

Experimental and Numerical Study on PDMS Collapse for Fabrication of Micro/Nanochannels

“…And it is difficult to fabricate silicon or glass nano-mold with low cost. In recent years, PDMS collapse method was proposed [28][29][30]. By this simple method PDMS micro/nanochannels can be fabricated with extremely low cost in only two steps (ie PDMS microchannels casting step and PDMS bonding step).…”