碱金属硫酸盐-十二烷基硫酸钠-聚乙二醇三元复合体系的束缚胶束特性

采用表面张力、稳态荧光猝灭和荧光分子探针技术研究了部分碱金属(锂、钠、钾)硫酸盐-十二烷基硫酸钠(Sod ium Dodecyl Su lfate SDS)-聚乙二醇(PEG)三元复合体系的聚集特性,发现加入碱金属硫酸盐后SDS仍以束缚胶束(bound m icelle)形式与PEG发生团簇化作用.表面张力实验表明,外加碱金属硫酸盐浓度c_e增加,体系的第一临界浓度c₁渐次降低,而第二临界浓度c₂略有增大,因而形成束缚胶束的浓度区间增宽;比饱和簇集量Γ_∞]随之增大,如加入50 mmol/L硫酸锂时,Γ_∞]增大了40%.稳态荧光猝灭实验表明,束缚胶束聚集数N_b随PEG浓度c_p线性减小,却随SDS浓度c线性增大,并呈c_e的单增函数关系;碱金属离子使N_b增大的能力按Li⁺++顺序增加,与碱金属水合离子半径减小的顺序相同.芘分子探针的荧光特性反映了束缚胶束的微环境极性随c和c_e增加而减小,随c_p增加而增大.

Characteristics of Bound Micelle in the Ternary Mixing System of Alkali Metal Sulfate-SDS-PEG

The ternary systems composed of some alkali metal(Li,Na and K) sulfate with sodium dodecyl sulfate(SDS) and polyethylene glycol(PEG) were studied by means of surface tension,steady-state fluorescence quenching and fluorescent molecule probe.The results show that the soft cluster formed spontaneously by PEG and the bound micelle of SDS in cases with or without alkali metal sulfate addition.The first critical concentration c_(1) decreased while the second critical concentration c_(2) increased slightly with ever-increasing level of alkali metal sulfate c_(e),therefore,the clusterization boundary of SDS-PEG extended.The specific saturation capacity of clusterization increased with the addition of alkali metal sulfate and it even increased 40% when 50 mmol/L Li_(2)SO_(4) was added to.The aggregation number of bound micelle N_(b) decreased linearly with the increase of PEG c_(p) while increased linearly as a function of c of SDS and increased monotonously as a function of c_(e).Since the radius of alkali metal hydrated ion increased in the order as follows: K~(+)(0.232(nm)<)Na~(+)(0.276 nm)Na~(+)>Li~(+).The characteristic fluorescence of the solubilized pyrene reveals that the polarity of bound(micelle) microenvironment decreased with the increase of the level of both c of SDS and c_(e)(Na_(2)SO_(4)),whereas(increases) with the increase of level of c_(p).