An Experimentally Fitted and Simple Model for the Pores in Nuclepore Membranes

Hernández, Antonio; Martínez-Villa, F.; Ibáñez, J. A.; Arribas, Juan Ignacio; Tejerina, A. F.

doi:10.1080/01496398608056142

Cited by 30 publications

(15 citation statements)

References 4 publications

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“…Nuclear-track-etched, e.g., Nuclepore, membranes have attracted much attention, particularly for separation applications in size-based filtration. − The effects of electric fields, both applied to and produced in these membranes, have generated much interest, ranging from understanding electrokinetic flow in cylindrical channels, − to the observation and explanation of periodic flux oscillations . Surface charge, a manifestation of the enhanced surface area-to-volume ratio ( A s / V ), is a critically important property influencing all these phenomena. , It determines the magnitude of the surface potential and the applicability of the Debye−Huckel approximation, and ultimately, it provides an experimental handle to adjust the microscopic processes that determine transport in the channel.…”

Section: Introductionmentioning

confidence: 99%

Electric Field Mediated Transport in Nanometer Diameter Channels

1998

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Nanoporous polycarbonate (PCTE) nuclear-track-etched membranes were used to effect electric field modulation of the mass transport of cationic, anionic, and neutral species in aqueous buffer. The permeability response to electric fields depended on the molecular charge and electrolyte concentration. Solute and solvent fluxes through nanopores under an electrical potential result from a balance of diffusion, electroosmosis, and ion migration. The Debye length, κ -1 , associated with the electrical double layer within the pores relative to the pore diameter, 2a, plays a critical role in determining electrokinetic transport behavior. The channel walls adsorb anions preferentially to produce a largely immobile negative charge density, leaving a large and mobile cation population to mediate transport in the channel. By adjusting the supporting electrolyte concentration, κa can be tuned such that the electrical double layer is either small in relation to the pore (κa g 1) or more diffuse and spanning the pore (κa < 1). Electroosmotic transport, mediated primarily by buffer cations, dominates when κa < 1. In this case the pores are essentially permselective, and anion electromigration is virtually eliminated. When κa g 1, the sign of the applied potential can be used to select for anion vs cation/neutral molecule transport.

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Section: Introductionmentioning

confidence: 99%

Electric Field Mediated Transport in Nanometer Diameter Channels

1998

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“…The derived detailed information on the pore shape is important for the correct interpretation of studied transport, electrokinetic, sorption, and other characteristics of TMs and TM-based secondary structures [3][4][5][6][7][8][9][10]. The method of the pore shape control based on the controlled decrease of the etching rate in the surface layer seems to be rather promising for both the improvement of parameters of micro-and ultrafiltration TMs and the design of other porous nanostructures.…”

Section: Discussionmentioning

confidence: 99%

“…However, thorough studies showed that, even in PC, the track pore shape is not always a circular cylinder. In some works, a "paradoxical" cigar-shaped profile was observed, which contradicted a conventional model of etching of heavy particle tracks in a homogeneous isotropic material [3][4][5][6][7][8][9][10]. Repeated attempts were made to explain the origin of this pore shape [6,8,9].…”

Section: Introductionmentioning

confidence: 95%

Factors determining pore shape in polycarbonate track membranes

et al. 2004

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The formation of pores in polycarbonate films irradiated by accelerated ions upon their treatment with alkali solution containing a surfactant was studied. It was found that the pore shape is determined by both the structure of the initial film and the peculiarities of interaction of a surfactant with a polymer surface and its transfer to a track. Because of the inhomogeneity of the initial material, the "track" pore cross section varies along the pore length. The presence of a surfactant leads to an additional effect. Being adsorbed onto the film surface and at the entrances of etched tracks of heavy ions, surfactant molecules tend to decrease the etching rate, thus leading to the formation of "spindle-shaped" pores. Thus, the use of a surfactant as a component of the chemical etching solution makes it possible to vary the pore shape of track membranes in a directional manner, optimizing their efficiency and selectivity.

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“…Pore density (4 × 10 9 cm −2 ) was determined by scanning electron microscope. Pore volume calculated based on the pore radius and pore density coincides within ±5% with the value measured as in paper [25] by the difference in the weights of a dry and wetted membrane. All chemicals used were of analytical grade.…”

Section: Membranes and Reagentsmentioning

confidence: 99%