title: Surface properties of Gemini surfactants with pyrrolidinium head groups.
abstract: Gemini surfactants C(n)-4-(n)PB (where n represents the alkyl chain length of 10, 12, 14 and 16) were synthesized and characterized. Their surface activity, thermodynamic properties, and aggregation behavior were investigated by means of surface tension, electrical conductivity, and steady-state fluorescence. It was found that the Gemini surfactants C(n)-4-(n)PB have superior surface activity to their corresponding monomer surfactants C(n)MPB as expected. Additionally, these compounds have lower cmc and surface tension in comparison with conventional cationic Gemini surfactants m-4-m. Thermodynamic parameters (ΔG(m)(0),ΔH(m)(0),TΔS(m)(0)) show that the micellization is an entropy driven process with shorter hydrophobic chain lengths but instead is enthalpy driven for longer hydrophobic chain lengths. The effect of the hydrophobic alkyl chain length and the addition of inorganic salt NaBr on the surface activity and micellization are in line with the conventional cationic Gemini surfactants.
authors.affiliation: College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Cai
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Dong
mesh_terms: D000327:Adsorption; D003198:Computer Simulation; D004553:Electric Conductivity; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D008958:Models, Molecular; D008968:Molecular Conformation; D011759:Pyrrolidines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013499:Surface Properties; D013500:Surface Tension; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D008823:Micelles; D011759:Pyrrolidines; D013501:Surface-Active Agents