Evaluation of rheology property of dodecyl maltoside, sucrose dodecanoate, Brij 35p and SDS stabilized O/W emulsion: effect of head group structure on rheology property and emulsion stability
Evaluation of rheology property of dodecyl maltoside, sucrose dodecanoate, Brij 35p and SDS stabilized O/W emulsion: effect of head group structure on rheology property and emulsion stability
复制标题
十二烷基麦芽糖苷、蔗糖十二烷酸酯、Brij 35p 和 SDS 稳定的 O/W 乳液的流变性能评价：头基结构对流变性能和乳液稳定性的影响
DOI：
10.1016/j.colsurfa.2004.08.072
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
M. Misran
中科院分区：
文献类型：
--
作者：
Boris B. Niraula;T. C. King;M. Misran
采用张力法和流变学方法对四种乳化剂的乳化性能进行了研究和比较。这些乳化剂在它们的烷基尾部（在这种情况下为C12）具有相同的碳数，但它们的头部基团结构不同。这些乳化剂的头基结构是麦芽糖、蔗糖、环氧乙烷和硫酸盐;提供其头基极性和HLB值彼此显著不同的同系物系列。不同浓度的乳化剂水溶液作为水相，石蜡油作为油相。所用的油与水的混合比为8：2。这自然地产生了高内相浓缩的水包油（O/W）乳液，其分散相体积分数为10.8，其中分散的液滴被组织以产生如由Wenen所述的密集堆积的多面体构型。这样的浓缩乳液将表现出令人感兴趣的流变学性质，包括剪切稀化行为和粘弹性效应。考虑到所有其他因素，如加工条件（通过剪切输入的能量和剪切时间），分散相的体积分数和连续相的粘度保持恒定，给定的混合比将产生水包油乳液，其液滴尺寸分布和多分散指数强烈依赖于用于其乳化的乳化剂的HLB值。这类乳液的流变性能强烈依赖于分散液滴的平均粒径分布，该粒径分布可随乳化剂的本体浓度和HLB值而变化。这些表面活性剂的界面和表面性质表明，分散相的液滴尺寸分布与所用乳化剂的HLB值和本体浓度密切相关。因此，很明显，这种乳液的流变学性质随着乳化剂的HLB值和本体浓度两者而强烈变化。这就是为什么流变学性质可以用来描述乳化剂的乳化效果和所得乳液的储存稳定性。正如所料，乳化剂的乳化效果，所得乳液的结构和它们的储存稳定性强烈地依赖于乳化剂的HLB值。由屈服应力、剪切粘度和储能模量可知，随着分散相液滴尺寸的减小，乳化度和储存稳定性均增强，随着乳化剂HLB值的减小，乳化度和储存稳定性均降低。随着乳化剂浓度的增加，乳化效果和乳液稳定性进一步提高。
Emulsifying property of four emulsifiers is being explored and compared using tensiometry and Rheology. These emulsifiers possess same number of carbon in their alkyl tail (C12in this case), but differ in their head group structure. The head group structure of these emulsifiers are maltose, sucrose, ethylene oxide and sulphate; providing a homologue series whose head group polarity and therewith HLB values differ significantly from each other. While aqueous emulsifier solutions of varying concentration were used as water phase, paraffin oil was used as oil phase. The oil to water mixing ratio used was 8:2. This naturally gave rise to high internal phase concentrated oil-in-water (O/W) emulsions with dispersed phase volume fractions of ≈0.8, in which the dispersed droplets are organized to give a densely packed polyhedron configuration as described by Princen. Such concentrated emulsions would exhibit interesting Rheology properties including shear-thinning behavior and viscoelastic effects. Given all other factors such as procession conditions (energy input through shearing and shearing time), volume fraction of the dispersed phase and viscosity of the continuous phase kept constant, the given mixing ratio would yield oil-in-water emulsions whose droplet size distribution and polydispersity index depended strongly on HLB value of the emulsifier used for their emulsification. The Rheology properties of such emulsions strongly depended on the average size distribution of the dispersed droplets that could be varied both with the bulk concentration and HLB value of the emulsifier. The interfacial and surface properties of these surfactants suggest that the droplet size distribution of the dispersed phase is strongly related to the HLB value and bulk concentration of the emulsifier used. Hence, it is evident that the Rheology properties of such emulsions vary strongly both with the HLB value and bulk concentration of the emulsifier. That is why the Rheology properties can be employed to describe both the emulsifying effect of the emulsifier and the storage stability of the resulting emulsion. As expected, the emulsifying effect of the emulsifier, the structure of the resulting emulsions and their storage stability depended strongly on HLB value of the emulsifier. As identified by yield stress, shear viscosity and storage modulus, both the degree of emulsification and storage stability enhanced with decreasing droplet size of the dispersed phase, and decreased with decreasing HLB value of the emulsifier used. Both the emulsifying effect and emulsion stability further were enhanced with increasing emulsifier concentration.