title: Aggregate transitions in aqueous solutions of sodium dodecylsulfate with a "gemini-type" organic salt.
abstract: Effects of a "gemini-type" organic salt 1,2-bis(2-benzylammoniumethoxy) ethane dichloride (BEO) on the aggregation behavior of sodium dodecylsulfate (SDS) have been investigated by turbidity, surface tension, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, (1)H NMR spectroscopy, and differential scanning microcalorimetry. The aggregation behavior of the SDS/BEO mixed aqueous solution shows strong concentration and ratio dependence. For the SDS/BEO solution with a molar ratio of 5:1, large loose irregular aggregates, vesicles, and long thread-like micelles are formed in succession with the increase of the total SDS and BEO concentration. Because BEO has two positive charges, the SDS/BEO solution may consist of the (SDS)(2)-BEO gemini-type complex, the SDS-BEO complex and extra SDS. The aggregation ability and surface activity of the SDS/BEO mixture exhibit the characteristics of gemini-type surfactants. Along with the results of DSC and (1)H NMR, the (SDS)(2)-BEO gemini-type structure is confirmed to exist in the system. This work provides an approach to construct the surfactant systems with the characteristics of gemini surfactants through intermolecular interaction between a two-charged organic salt and oppositely charged single-chain surfactants.
authors.affiliation: Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Defeng
authors.initials: D
authors.lastname: Yu
authors.forename: Maozhang
authors.initials: M
authors.lastname: Tian
authors.forename: Yaxun
authors.initials: Y
authors.lastname: Fan
authors.forename: Gang
authors.initials: G
authors.lastname: Ji
authors.forename: Yilin
authors.initials: Y
authors.lastname: Wang
mesh_terms: D050339:Benzylammonium Compounds / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010316:Particle Size; D044367:Phase Transition; D012492:Salts / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: C575298:1,2-bis(2-benzylammoniumethoxy)ethane dichloride; D050339:Benzylammonium Compounds; D012492:Salts; D012996:Solutions; D014867:Water; D012967:Sodium Dodecyl Sulfate