Electrochemical impedance spectroscopy studies of organic-solvent-induced permeability changes in nanoporous films derived from a cylinder-forming diblock copolymer
© 2011 American Chemical Society
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 27(2011), 17 vom: 06. Sept., Seite 11111-7 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2011
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Membranes, Artificial Polymethacrylic Acids Polystyrenes Solvents poly(styrene-co-ethyl methacrylate) |
| Zusammenfassung: | © 2011 American Chemical Society In this paper we report electrochemical investigations of the influence of organic solvents dissolved in aqueous solution on the permeability of nanoporous films derived from a cylinder-forming polystyrene-poly(methyl methacrylate) diblock copolymer (CF-PS-b-PMMA). The nanoporous films (ca. 30 nm in pore diameter) were prepared on planar gold electrodes via UV-based degradation of the cylindrical PMMA domains of annealed CF-PS-b-PMMA films (30-45 nm thick). The permeability of the electrode-supported nanoporous films was assessed using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The faradic current of Fe(CN)(6)(3-/4-) decreased upon immersion in aqueous solutions saturated with toluene or methylene chloride (5.8 mM and 0.20 M, respectively). EIS data indicated that the decrease in faradic current mainly reflected an increase in the pore resistance (R(pore)). In contrast, R(pore) did not change in a saturated n-heptane solution, 0.17 M ethanol, or 5.8 mM aqueous solutions of methylene chloride, diethyl ether, methyl ethyl ketone, or ethanol. Atomic force microscopy images of a nanoporous film in aqueous solution with and without 5.8 mM toluene showed a reversible change in the surface morphology, which was consistent with a toluene-induced change in R(pore). The solvent-induced increase in R(pore) was attributed to the swelling of the nanoporous films by the organic solvents, which decreased the effective pore diameter. The reversible permeability changes suggest that the surface of CF-PS-b-PMMA-derived nanoporous films can be functionalized in organic environments without destroying the nanoporous structure. In addition, the solvent-induced swelling may provide a simple means for controlling the permeability of such nanoporous films |
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| Beschreibung: | Date Completed 29.12.2011 Date Revised 31.08.2011 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/la202005n |