Morphological Changes of Monolayers of Two Polymerizable Pyridine Amphiphiles upon Complexation with Cu(II) Ions at the Air−Water Interface

Abstract

Morphological changes of monolayers of two polymerizable pyridine amphiphiles upon complexation with Cu(II) ions at the air-water interface Werkman, P.J.; Schouten, A.J.; Noordegraaf, M.A.; Kimkes, P.; Sudhölter, E.J.R. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of recordPublication date : 1998 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Werkman, P. J., Schouten, A. J., Noordegraaf, M. A., Kimkes, P., & Sudhölter, E. J. R. (1998). Morphological changes of monolayers of two polymerizable pyridine amphiphiles upon complexation with Cu(II) ions at the air-water interface. Langmuir, 14(1), 157 -164. DOI: 10.1021/la970576a Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. The monolayer behavior of two amphiphilic, diacetylenic units containing pyridine ligands at the airwater interface is studied by measuring the surface pressure-area isotherms and by Brewster angle microscopy (BAM). Both amphiphiles form stable monolayers at the air-water interface. The amphiphile containing an ester group shows a well-defined liquid-expanded (LE) to liquid-condensed (LC) phase transition, while the amphiphile with the amide group forms only a condensed monolayer film at 9.4°C. For both amphiphiles, addition of CuCl 2 to the subphase causes an increase of the surface pressure (Πc) at which the phase transition appears, suggesting the formation of a coordination complex at the airwater interface. Addition of Cu(ClO4)2 to the subphase instead of CuCl2 causes an even larger increase in Πc, indicating that more copper ions bind to the monolayer which results in a more charged monolayer. On a pure water subphase, Brewster angle microscopy of the monolayer of the ester-containing ligand shows the formation of spiral dendritic crystalline domains at the plateau in the isotherm near the solid state region. The formation of spiral crystalline domains indicates that the LC phase is L1′. The amidecontaining ligand, however, forms two-dimensional crystalline domains directly after spreading at the air-water interface, which are pushed together upon compression. No chiral crystalline domains were observed for this amphiphile indicating that the ester and amide amphiphile have a different LC phase. Both amphiphiles spread...

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