Interaction of the Biosurfactant, Surfactin with Betaines in Aqueous Solution

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• 作者：Fang Liu ; Jingwen Xiao ; Vasil M. Garamus ; L谩szl贸 Alm谩sy ; Regine Willumeit ; Bozhong Mu ; Aihua Zou
• 刊名：Langmuir
• 出版年：2013
• 出版时间：August 27, 2013
• 年：2013
• 卷：29
• 期：34
• 页码：10648-10657
• 全文大小：500K
• 年卷期：v.29,no.34(August 27, 2013)
• ISSN：1520-5827

文摘

The interactions between the lipopeptide Surfactin and four betaines, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SDDAB), N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (STDAB), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SHDAB), and N-dodecyl-N,N-dimethyl-2-ammonio-acetate (C₁₂BE) are studied by surface tension and small-angle neutron scattering (SANS). SDDAB, STDAB, and SHDAB have the same headgroup but different hydrophobic chains. C₁₂BE has different headgroup but the same hydrophobic chain with SDDAB. According to the interfacial parameters calculated from surface tension, the synergism between Surfactin and betaine is relevant with the molecule structure of betaine and the mole ratio of them. For betaines, the optimum alkyl chain length (STDAB) and long enough separation between positive charge and negative charge in headgroup are responsible for highest synergetic interaction with Surfactin. The aggregates of individual Surfactin and the mixtures of Surfactin and sulfopropyl betaines are predicted to be spherical based on the packing parameter (pp) and the average packing parameter (P_av), which is in close qualitative agreement with SANS data analysis, while Surfactin/C₁₂BE forms ellipsoidal micelles due to the smaller headgroup of C₁₂BE.