反离子对十二烷基麦芽糖苷复配体系表面活性和胶束性质的影响

Effect of counter ions on surface activity and micellar properties of n-dodecyl-β-D-maltoside blend systems

通过表面张力法和荧光探针法研究了非离子表面活性剂n-十二烷基-β-D-麦芽糖苷(DDM)分别与阴离子表面活性剂十二烷基硫酸钠(NaDS)、十二烷基硫酸铵(NH4DS)和十二烷基硫酸镁(Mg(DS)2)组成的二元复配体系的表面活性及胶束性质,考察了反离子对3种复配体系分子间相互作用参数(β)、胶束组成、热力学性质及微环境参数的影响。结果表明,NH4DS/DDM复配体系较其他2个体系具有更低的cmc和γcmc;3种复配体系分子间相互作用参数和混合自由能(ΔGM)均为负值,即2组分间存在协同效应,混合胶束形成是自发过程;且NH4DS/DDM复配体系的ΔGM最小,NH4DS/DDM混合胶束聚集数比其他2个体系小。由此推断NH4DS与DDM的相互作用机理为NH4DS分子上的NH4+与DDM分子葡糖基上的羟基形成氢键,使得NH4DS/DDM混合胶束更易自发形成。

Surface activity and micellar properties of binary surfactant systems containing a nonionic surfactant viz. π - dodecyl -β - D - mahoside （ DDM ） and separately blended with an anionic surfactant viz. sodium dodecyl sulphate （NaDS）, ammonium dodecyl sulphate （NH4DS） and magnesium dodecyl sulphate （Mg（DS）2 ） in water were investigated via surface tension and fluorescence probe methods. The effects of counter ions on the intermolecular action parameter （β）, the composition of blended surfactants, thermodynamic properties and microenvironmental parameter were examined. Results showed that the critical micelle concentration （cmc） and surface tension at emc （γcmo） of NH4DS/DDM blend are lower than other two blended surfactant systems. Both intermolecular action parameter and mixing free energy （△GM ） of the three blended surfactant systems are negative values. Such results indicated that strong synergistic effect exists between the two components of micelles of the blended surfactants as well as the formation of the micelles is a spontaneous process. It was found that the △GM and aggregation number for NH4DS/DDM micelle are lower than that of the other two blends. Based upon these results, deduction could be made that the mechanism of intermolecular action between NH4DS and DDM is due to hydrogen bond created between NH4^＋ group of NH4DS and hydroxy group of DDS and causing them to be more easily to form blended micelles spontaneously.