Stabilization of alkylated azacrown ether by fatty acid at the air-water interface.
The adsorbed amount of partially deuterated dihexadecyl-diaza-18-crown-6 ether (d-ACE16) in the presence of different chain length fatty acids as a function of surface pressure was determined by neutron reflectometry technique. The highest adsorbed amount of the azacrown ether was observed for the mixture of ACE16 with hexadecanoic (palmitic) acid, pointing to the importance of chain length matching between the two species for optimum stabilization of the mixed monolayer. The contrast variation technique was used to estimate the contribution to the total adsorbed amount from stearic acid and ACE16. It was found that the mixed Langmuir monolayer is stable against dissolution up to a surface pressure of 20 mN m(-1). Above this pressure, however, the spread and adsorbed amounts start to deviate, indicative of partial dissolution into the aqueous subphase. The consequences of this behavior for the transport of metal ions through the interfaces of permeation liquid membranes (PLMs) are discussed.
School of Biological & Chemical Sciences, Queen Mary, University of London, Joseph Priestley Building, Mile End Road, London E1 4NS, United Kingdom. a.zarbakhsh@qmul.ac.uk
Ali
A
Zarbakhsh
Mario
M
Campana
John R P
JR
Webster
Kamil
K
Wojciechowski
D000327:Adsorption; D000388:Air; D043844:Crown Ethers / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D009502:Neutrons; D012542:Scattering, Radiation; D013229:Stearic Acids / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014867:Water
D043844:Crown Ethers; D004987:Ethers; D005227:Fatty Acids; D008670:Metals; D013229:Stearic Acids; D014867:Water; C031183:stearic acid; C015762:18-crown-6