title: Partitioning of small amphiphiles at surfactant bilayer/water interfaces: an avoided level crossing muon spin resonance study.
abstract: The temperature-dependent variation of local environment and reorientation dynamics of the small amphiphile 2-phenylethanol in lamellar phase dispersions of the dichain cationic surfactants, 2,3-diheptadecyl ester ethoxypropyl-1,1,1-trimethylammonium chloride (DHTAC) and dioctadecyldimethylammonium chloride (DODMAC), and the nonionic surfactant, tetra(ethylene glycol) n-dodecyl ether (C12E4), have been determined using avoided level crossing muon spin resonance spectroscopy (ALC-muSR). For cosurfactant radicals the hydrophobic or hydrophilic character of the surrounding media can be determined from their magnetic resonance signatures. Comparison of the three different bilayer-forming surfactant systems shows that the ALC-muSR technique is able to distinguish both major and subtle differences in the partitioning of the cosurfactant radicals between the different systems.
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Scheuermann
authors.forename: Ian M
authors.initials: IM
authors.lastname: Tucker
authors.forename: Herbert
authors.initials: H
authors.lastname: Dilger
authors.forename: Ed J
authors.initials: EJ
authors.lastname: Staples
authors.forename: Gary
authors.initials: G
authors.lastname: Ford
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Fraser
authors.forename: Bettina
authors.initials: B
authors.lastname: Beck
authors.forename: Emil
authors.initials: E
authors.lastname: Roduner
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005609:Free Radicals / Q000737:chemistry; D008567:Membranes, Artificial; D008651:Mesons; D015394:Molecular Structure; D010626:Phenylethyl Alcohol / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D005609:Free Radicals; D008567:Membranes, Artificial; D013501:Surface-Active Agents; D014867:Water; D010626:Phenylethyl Alcohol