碱金属硫酸盐-SDS-PEG三维浓度变化对SDS的束缚胶束聚集数的影响

采用稳态荧光猝灭技术测定了三种碱金属(Li, Na或K)硫酸盐-SDS-PEG三元体系中SDS(十二烷基硫酸钠)的束缚胶束聚集数N_b, 考察了SDS浓度c、碱金属硫酸盐浓度c_e及PEG(聚乙二醇)浓度c_p变化时SDS的N_b的变化规律. 对SDS的N_b数据进行二次响应面分析, 得知SDS的N_b是c的线性增大函数、c_e的对数函数以及c_p的反比例函数, 据此对SDS的N_b实验值建立含二次交互作用项的函数表达式. 按上述表达式进行回归, 得到相应于Li₂SO₄, Na₂SO₄或K₂SO₄体系的系数a₀～a₈. 据此计算得到SDS的N_b预期值并与实验值进行比较, 其间的绝对误差在3以内, 相对误差在4%以内. 该结果为用SDS的N_b 预测表面活性剂-大分子软模板的尺寸和化学微环境、并用于调控所制备的金属纳米粒子的大小提供依据.

Aggregation Number of Bound-Micelle of SDS Expressed as Function of the Ternary Concentrations of Alkali Metal Sulfate, SDS and PEG

The steady-state fluorescence quenching method was used to determine the aggregation number of bound-micelle (N_b) of sodium dodecyl sulfate (SDS) in the ternary mixing system of alkali metal (Li, Na or K) sulfate-SDS-polyethylene glycol (PEG). The altering tendency of N_b with the change of concentration of SDS (c), alkali metal sulfate (c_e) and PEG (c_p) was investigated. The response surface modeling to the N_b of SDS was done, which revealed that the N_b of SDS took approximately the linear increase function of c, the logarithmic function of c_e and in reverse proportion to c_p simultaneously. Consequently the equation including the quadratic interaction terms was established. The coefficients a₀～a₈ in the above equation corresponding to Li₂SO₄, Na₂SO₄ and K₂SO₄ were regressed from the experimental N_b, respectively. The absolute errors between experimental and prospective N_b were less than 3 and the relative ones between them were less than 4%. This equation was useful to anticipate by N_b of surfactants the size and chemical microenvironment of soft template composed by surfactants with macromolecules in the presence of inorganic electrolytes, and to adjust the size of metal-nanoparticles prepared by means of the soft template furthermore.