“…The spiral growth of the crystalline domains is somewhat surprising because it suggests that these domains are chiral, although amphiphile B is achiral. This behavior was also observed by other research groups − for achiral fatty acids and their esters. The spiral effects can only be accounted for when it is assumed that the liquid-condensed phase is the so-called L 1 ‘ phase.…”
Section: Resultssupporting
confidence: 87%
“…The spiral effects can only be accounted for when it is assumed that the liquid-condensed phase is the so-called L 1 ‘ phase. This phase is a tilted mesophase in which the molecules have a tilt azimuth in a direction intermediate between the nearest neighbor and next-nearest neighbor. , The L 1 ‘ phase has a broken reflection symmetry 39 which causes the spiral structures observed by fluorescence microscopy 39,40 and BAM 42 for achiral compounds. 8 BAM images of the ester monolayer at 9.4 °C corresponding to the points of the Π− A isotherm of the ester compound (Figure ).…”
Section: Resultsmentioning
confidence: 99%
“…When Cu(ClO 4 ) 2 is added to the subphase again at large surface areas (>61 Å 2 ·molecule -1 ), the LE and G phases coexist, but at Π c (image f of Figure ) circular domains are formed, which grow when the surface area is decreased (image g of Figure ). Again, the appearance of chirality identifies the LC phase as L 1 ‘ …”
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...
“…The spiral growth of the crystalline domains is somewhat surprising because it suggests that these domains are chiral, although amphiphile B is achiral. This behavior was also observed by other research groups − for achiral fatty acids and their esters. The spiral effects can only be accounted for when it is assumed that the liquid-condensed phase is the so-called L 1 ‘ phase.…”
Section: Resultssupporting
confidence: 87%
“…The spiral effects can only be accounted for when it is assumed that the liquid-condensed phase is the so-called L 1 ‘ phase. This phase is a tilted mesophase in which the molecules have a tilt azimuth in a direction intermediate between the nearest neighbor and next-nearest neighbor. , The L 1 ‘ phase has a broken reflection symmetry 39 which causes the spiral structures observed by fluorescence microscopy 39,40 and BAM 42 for achiral compounds. 8 BAM images of the ester monolayer at 9.4 °C corresponding to the points of the Π− A isotherm of the ester compound (Figure ).…”
Section: Resultsmentioning
confidence: 99%
“…When Cu(ClO 4 ) 2 is added to the subphase again at large surface areas (>61 Å 2 ·molecule -1 ), the LE and G phases coexist, but at Π c (image f of Figure ) circular domains are formed, which grow when the surface area is decreased (image g of Figure ). Again, the appearance of chirality identifies the LC phase as L 1 ‘ …”
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...
“…This can explain the observations for DL-DPPE monolayers, in which the defects anneal very slowly and the textures formed are very irregular. However, at slightly lower compression rates (5.0 X 10-1 nm2 molecule-1 min-1), a texture similar to the segment structures in monolayers of fatty acids (Henon and Meunier, 1993), fatty acid ethyl and methyl esters (Qiu et al, , 1992aOverbeck et al, 1994), and 1-monoglycerides (Vollhardt et al, 1993;Weidemann et al, 1995;Gehlert et al, 1995;Brezesinski et al, 1995) occurs (Fig. 8 e).…”
Monolayers of dipalmitoyl-phosphatidyl-N-monomethylethanolamine (DPP(Me)E) and dipalmitoyl-phosphatidyl-N,N-dimethylethanolamine (DPP(Me2)E) are studied and compared with dipalmitoyl-phosphatidylethanolamine (DPPE), dimyristoyl-phosphatidylethanolamine (DMPE), and dipalmitoyl-phosphatidylcholine (DPPC) to characterize the influence of the headgroup size. The properties of the condensed phases of DPP(Me2)E and DPP(Me)E are between those of DPPC and DMPE or DPPE. DPPC domains are elongated and the orientation changes continuously, whereas DMPE domains are compact and the orientation jumps at curved lines. The domains of DPP(Me2)E and DPP(Me)E are compact, and not elongated. The orientation changes continuously by 360 degrees around a point in the centered domains, and jumps of the orientation occur only in the case of twinning. Furthermore, the size of the headgroup influences the erection of the aliphatic chains. For DPPC and (DPP(Me2)E), no complete erection of chains occurs, whereas for DPP(Me)E the surface pressure required for the complete erection of chains is much higher than for DPPE. The same tendency is found for the collapse. DPPC monolayers do not collapse. DPP(Me2)E monolayers collapse at a much higher surface pressure than those of DPP(Me)E and DPPE.
“…The straight edge defects are indicative of a nonchiral structure like that of the L, (chains tilted towards nearest neighbors) or L,* (chains tilted midway between nearest neighbors) phases, while the curved edge defects identify the condensed phase as the L,' (chains tilted in an intermediate direction) phase, which has an inherently chiral structure. In the fatty acids at low temperatures and low areas with no LE phase present, large stripes of varying fluorescence intensity and point-like defects were observed (Qiu et al, 1992;Ruiz-Garcia, 1992), as shown in Figure 6.…”
Section: Fatty Acid and Ester Monolayersmentioning
The technique of fluorescence microscopy enables imaging of coexisting domains in Langmuir monolayers which have been doped with a small amount of a fluorescent probe. It is also possible to image surface aggregates formed by labeled proteins interacting with phospholipid monolayers. The method has provided information concerning phase behavior and structure of monolayers and proven useful in the study of monolayers as model systems of membrane processes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
