title: Interaction of a biosurfactant, Surfactin with a cationic Gemini surfactant in aqueous solution.
abstract: The interaction between biosurfactant Surfactin and cationic Gemini surfactant ethanediyl-1,3-bis(dodecyldimethylammonium bromide) (abbreviated as 12-3-12) was investigated using turbidity, surface tension, dynamic light scattering (DLS) and small angle neutron scattering (SANS). Analysis of critical micelle concentration (CMC) values in Surfactin/12-3-12 mixture indicates that there is synergism in formation of mixed Surfactin/12-3-12 micelles. Although Surfactin and 12-3-12 are oppositely charged in phosphate buffer solution (PBS, pH7.4), there are no precipitates observed at the concentrations below the CMC of Surfactin/12-3-12 system. However, at the concentration above CMC value, the Surfactin/12-3-12 mixture is severely turbid with high 12-3-12 content. DLS and SANS measurements follow the size and shape changes of mixed Surfactin/12-3-12 aggregates from small spherical micelles via elongated aggregates to large bulk complexes with increasing fraction of Gemini surfactant.
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Jin
authors.affiliation: Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Materials Research, Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
authors.forename: Vasil M
authors.initials: VM
authors.lastname: Garamus
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Materials Research, Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Eckerlebe
authors.affiliation: Helmholtz-Zentrum Geesthacht, Centre for Materials and Coastal Research, Institute of Materials Research, Max-Planck-Strasse 1, 21502 Geesthacht, Germany.
authors.forename: Regine
authors.initials: R
authors.lastname: Willumeit-Römer
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
authors.forename: Bozhong
authors.initials: B
authors.lastname: Mu
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China. Electronic address: aihuazou@ecust.edu.cn.
authors.forename: Aihua
authors.initials: A
authors.lastname: Zou
mesh_terms: D002412:Cations / Q000737:chemistry; D055666:Lipopeptides / Q000737:chemistry*; D008823:Micelles; D010316:Particle Size; D010456:Peptides, Cyclic / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D002412:Cations; D055666:Lipopeptides; D008823:Micelles; D010456:Peptides, Cyclic; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D013501:Surface-Active Agents; C533917:trimethylene-1, 3-bis (dodecyldimethylammonium bromide); D014867:Water; C009365:surfactin peptide
keywords: Gemini surfactant; Micelle; SANS; Surface tension; Surfactin