Effect of hydrodynamic interaction on flow-induced polymer translocation through a nanotube

Ding, Mingming; Duan, Xiaozheng; Yuyuan, LU; Shi, Tongfei

doi:10.1007/s40242-015-5001-x

Cited by 2 publications

(2 citation statements)

References 40 publications

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“…Clearly, the result demonstrates that the energy state of each preconfined segment/blob shows almost no dependence on the chain length, which implies that from a viewpoint of thermodynamics the influence of preconfinement effect on the critical flow rate of flexible linear chains might also be chain length independent. This finding satisfactorily explains the widely reported independence of q c from the chain length in related theoretical ,,,,,− and experimental studies, ,,, even though the preconfinement effect was never taken into consideration. In addition, we expect that the preconfinement may influence the initial chain conformation, the capture process, and the translocation kinetics, which are all essential in the flow-induced polymer translocation.…”

Section: Resultssupporting

confidence: 84%

Origin of Inconsistency in Experimentally Observed Transition Widths and Critical Flow Rates in Ultrafiltration Studies of Flexible Linear Chains

Tao

Yang

et al. 2018

Macromolecules

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Using special anisotropic membranes of bilayered cylindrical channels, we have experimentally clarified the origin of inconsistency in the transition widths and critical flow rates (q c ) reported in related ultrafiltration studies of flexible linear chains. By studying the retention behavior of linear polystyrene chains passing through the same bilayered ultrafiltration membrane but in different translocation models, we reveal that the interaction among flow fields and the preconfinement effect are responsible for the previously observed inconsistency. In theory, only a single pore and a single chain are considered, but many pores and chains exist in experiment. The interaction among flow fields generated at different pore entrances could lead to the elongation/turbulent mixed flow fields, which will result in some unpredictable motions of polymer chains, such as the rotation, compression, reversed pulling, etc. Accordingly, much larger q c values and a broader transition were observed in experiments. On the basis of our previous free-draining model and present results, we propose a revised model by considering the partially draining nature of one confined blob, which provides a simple way for the rough estimation of the degree of draining for one confined blob in good solvents. Besides, the results also reveal that the preconfinement effect could lead to a reduced conformation entropy and an increased preconfinement energy for a polymer chain before its translocation through a small cylindrical pore, but such an influence seems to be chain length independent when the normalized confinement energy is compared. It satisfactorily explains why the critical flow rate is widely reported to be chain length independent, even though the preconfinement effect is not taken into consideration in related studies. Finally, our control experiment reconfirms that the asymmetry of bilayered membrane, instead of the variation of effective pore size, is the origin for the different ultrafiltration behavior of linear chains in different translocation models.

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Section: Resultssupporting

confidence: 84%

Origin of Inconsistency in Experimentally Observed Transition Widths and Critical Flow Rates in Ultrafiltration Studies of Flexible Linear Chains

Tao

Yang

et al. 2018

Macromolecules

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“…More importantly, eq predicts that the critical flow rate q c is independent of the chain length. Such a prediction has been supported by numerous theoretical work, ,,,, computational simulation, − and experimental observation. − Unfortunately, this prediction simultaneously means that the flow-driven ultrafiltration is not a feasible method for the fractionation/separation of linear polymers with different chain lengths.…”

Section: Introductionmentioning

confidence: 97%

Revisiting the Flow-Driven Translocation of Flexible Linear Chains through Cylindrical Nanopores: Is the Critical Flow Rate Really Independent of the Chain Length?

et al. 2018

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We aim to clarify how the chain length influences the critical flow rate (q c ) for flexible linear chains translocating through cylindrical nanopores in the whole length range (9.5 > R/r > 1.0), where R and r represent the chain size and the pore size, respectively. By studying the translocation behavior of both mono-and polydisperse polystyrenes through 20 nm nanopores, we have, for the first time, experimentally revealed that there exist two different translocation regimes, i.e., strong and moderate confinement regimes. In the strong confinement regime (R/r > λ*), q c is found to be independent of the chain length, consistent with the prediction by classical theories, while in the moderate confinement regime (R/r < λ*), q c increases with the chain length significantly, where λ* represents the critical relative chain length. Theoretically, λ* is determined by the critical penetration length (l*), at which the free energy change (ΔE) of a translocating chain reaches its maximum value (ΔE ∼ k B T). For longer chains (R/r > λ*), they always reach the position l* of the barrier (E bar *) before being completely confined in the channel; but for shorter chains (R/r < λ*), they could overcome the energy barrier before reaching l*. By considering the variation of both position (L) and height (E bar ) of the energy barrier in the moderate confinement regime, a normalization equation has been proposed to correlate the normalized critical flow rate (q c /q c *) with the normalized confined length (L/l*) and energy barrier (E bar /E bar *), i.e., q c /q c * = (2L/l* − E bar / E bar *)/(L/l*) 2 , where q c *, l*, and E bar * are the corresponding physical quantities in the strong confinement regime. The theoretical equation describes our experimental data well. In addition, we discuss the possibility of utilizing single membranebased ultrafiltration for linear polymer fractionation. The experimental result demonstrates that one single membrane is enough to simultaneously tailor the boundaries of low and high molar masses of polymer fractions in ultrafiltration fractionation. As an example, we experimentally show how one can "dynamically" regulate the effective pore size of a given membrane, by properly choosing the flow rates, to fractionate a polydisperse sample (M w /M n ∼ 3.25) into a series of monodispersed samples (1.08 ≤ M w /M n ≤ 1.30) with different boundary molar masses. The current work not only strengthens our understanding of the lengthdependent translocation behavior of linear polymers but also provides a versatile method for linear chain fractionation.

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Effect of hydrodynamic interaction on flow-induced polymer translocation through a nanotube

Cited by 2 publications

References 40 publications

Origin of Inconsistency in Experimentally Observed Transition Widths and Critical Flow Rates in Ultrafiltration Studies of Flexible Linear Chains

Origin of Inconsistency in Experimentally Observed Transition Widths and Critical Flow Rates in Ultrafiltration Studies of Flexible Linear Chains

Revisiting the Flow-Driven Translocation of Flexible Linear Chains through Cylindrical Nanopores: Is the Critical Flow Rate Really Independent of the Chain Length?

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