Electrophoresis of Deformable Polyelectrolytes in a Nanofluidic Channel

Tseng, Shiojenn; Lin, Chih‐Yuan; Hsu, Jyh‐Ping; Yeh, Li‐Hsien

doi:10.1021/la304842x

Cited by 12 publications

(10 citation statements)

References 56 publications

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“…Using a Cartesian coordinate system x i , this "real" force density is defined according to (12) (see also Ref. 17) in terms of the ambient induced electric charge and electric field (q (E) , ϕ (E) ), as f (E)…”

Section: B the Hydrodynamic Problemmentioning

confidence: 99%

“…Thus, the parameter ξ ≥ 1 depends monotonically on the EDL thickness and assuming that λkb ≤ 1, is uniquely given by (39) in terms of the Debye scale λ 0 and the averaged wall-zeta potential ζ s . Our next task is to determine the steady component of the EOF velocity v (E) s , governed by the inhomogeneous Stokes equation (12), where now (ϕ, q, χ ) are replaced by (ϕ (E) , q (E) , χ (E) ) defined in (31), (32) and (35). The forced Stokes momentum equation (12) together with (9), can be written in terms of the electric parameters as…”

Section: Tw-eof In a Cylindrical Nanoporementioning

confidence: 99%

“…1 As manufacturing technology develops, we witness a revolution in attempting to miniaturize the fluidic components in lab-on-a-chip devices from the micro and into the nano-scale, including the use of nanotubes or nanopores for fluid transport. [2][3][4][5][6][7][8][9][10][11][12][13] Although the fields of micro-and nanofluidics are often grouped together, in truth, the transition from microfluidic systems to those at the nano-scale begets a host of new physical phenomena that do not exist (or have negligible effect) at the micro-scale, in a manner similar to that which was observed in the macro-micro-scale transition. One particularly important example in electrokinetic applications is the emergence of a "thick" electric double layer (EDL).…”

Section: Introductionmentioning

confidence: 99%

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Travelling wave dipolophoresis of ideally polarizable nano-particles with overlapping electric double layers in cylindrical pores

Miloh

Boymelgreen

2014

Physics of Fluids

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Regimes of streaming potential in cylindrical nano-pores in presence of finite sized ions and charge induced thickening: An analytical approach T. Miloh and A. Boymelgreen Phys. Fluids 26, 072101 (2014) case, the Helmholtz-Smoluchowski (HS) slip-velocity may be implemented as a boundary condition in the Stokes equation, effectively bypassing the need to consider the electrostatic (Coulomb) forces in the momentum equation, thus considerably simplifying the analysis. However, if the particle radius or channel width is of the same order as the EDL (nano-size), this approximation ceases to be valid and it becomes necessary to resolve the EDL as well as any remaining bulk solute according to the full Poisson-Nernst-Planck (PNP) formulation together with the inhomogeneous Stokes equation, incorporating the Coulombic force density. Further complication arises if the suspended particles are conducting or polarizable, in which case the applied field will "induce" polarization within each particle, which is then shielded by a corresponding electric double layer. 14-17 In a confined system, this double layer formed around the colloid can interact with the EDL at the channel wall, resulting in a highly nonlinear problem. It is emphasized here that in contrast to the more well-known "linear" electroosmotic effect, the "induced-charge" effect is dependent only on the polarizability of the particle or wall and not on its native charge. Thus, in order to focus on the induced contribution, bounding surfaces are generally considered initially uncharged. In fact, it is well known that under the application of AC fields, the linear effects average to zero over a single cycle, while for the case of DC or biased AC forcing, it is possible -at least to first-order -to superimpose the linear and nonlinear solutions.Our ambitious goal in the present study is to develop a general framework for evaluating the phoretic motion (translation and rotation), induced by an arbitrary externally applied electric field, on polarizable (uncharged) nano particles, freely suspended in a nano-channel with conducting walls and filled with an electrolyte. It is important to note that no restrictions are imposed on the geometrical shape of the particle or the enclosing nanopore.The consideration of a conducting wall boundary condition, which results in a background induced electroosmotic flow (EOF) that is nonlinear in the applied field, is the first factor which differentiates this work from the classical approach to other bounded cases, wherein the channel walls are generally considered to be insulating and subject to linear electroosmosis (see, for example, Refs. 5 and 6). Practically, such a boundary condition accounts for geometries in which the active electrodes are embedded in the channel wall. In order to solve this nonlinear ambient electroosmotic flow in a nanochannel, the potential overlap of the EDLs induced at the channel walls must be accounted for in such a way that equilibrium cannot be assumed a priori to occur away (e.g., along the ch...

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Section: B the Hydrodynamic Problemmentioning

confidence: 99%

Section: Tw-eof In a Cylindrical Nanoporementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Travelling wave dipolophoresis of ideally polarizable nano-particles with overlapping electric double layers in cylindrical pores

Miloh

Boymelgreen

2014

Physics of Fluids

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“…The thickness of EDL is dominated by the ionic concentration of the buffer solutions (Li 2004), however, pH values (Hsu et al 2012b;Wang et al 2013) and symmetry or asymmetry property of the ions (O'Brien and White 1978;Semenov et al 2013;Nedelcu and Sommer 2014;Liu et al 2016) also affect the electrophoretic behavior. For the cases of particle motion in cylindrical channels, generally, the particles move along the centerlines of the channels (Keh and Chiou 1996;Shugai and Carnie 1999;Tseng et al 2013), however, the off-centerline effect has also been investigated (Zhang et al 2009;Lee and Keh 2014;Liu et al 2014). Zeta potential of the particle surfaces is another key parameter in the electrophoresis.…”

Section: Introductionmentioning

confidence: 99%

Electrokinetic motion of single nanoparticles in single PDMS nanochannels

Peng

2017

Microfluid Nanofluid

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Electrokinetic motion of single nanoparticles in single nanochannels was studied systematically by image tracking method. A novel method to fabricate PDMS-glass micronanochannel chips with single nanochannels was presented. The effects of ionic concentration of the buffer solution, particle-to-channel size ratio and electric field on the electrokinetic velocity of fluorescent nanoparticles were studied. The experimental results show that the apparent velocity of nanoparticles in single nanochannels increases with the ionic concentration when the ionic concentration is low and decreases with the ionic concentration when the concentration is high. The apparent velocity decreases with the particle-to-channel size ratio (a/b). Under the condition of low electric fields, nanoparticles can hardly move in single nanochannels with a large particle-to-channel size ratio. Generally, the apparent velocity increases with the applied electric field linearly. The experimental study presented in this article is valuable for future research and applications of transport and manipulation of nanoparticles in nanofluidic devices, such as separation of charged nanoparticles and DNA molecules.

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“…Therefore, it is important to consider aforementioned electrostatic phenomena to develop a comprehensive model of polyelectrolytes in micro/nanochannels. A series of researches results regarding colloidal particle conducting electrophoretic motion within a cylindrical channel has been reported in the literature [20], [21].…”

Section: Introductionmentioning

confidence: 99%