Golemanov Konstantin, Tcholakova Slavka, Denkov Nikolai, Pelan Eddie, Stoyanov Simeon D
Unilever R&D, Vlaardingen, The Netherlands.
Soft Matter. 2014 Sep 28;10(36):7034-44. doi: 10.1039/c4sm00406j.
Saponins are a diverse class of natural, plant derived surfactants, with peculiar molecular structure consisting of a hydrophobic scaffold and one or several hydrophilic oligosaccharide chains. Saponins have strong surface activity and are used as natural emulsifiers and foaming agents in food and beverage, pharmaceutical, ore processing, and other industries. Many saponins form adsorption layers at the air-water interface with extremely high surface elasticity and viscosity. The molecular origin of the observed unique interfacial visco-elasticity of saponin adsorption layers is of great interest from both scientific and application viewpoints. In the current study we demonstrate that the hydrophobic phase in contact with water has a very strong effect on the interfacial properties of saponins and that the interfacial elasticity and viscosity of the saponin adsorption layers decrease in the order: air > hexadecane ≫ tricaprylin. The molecular mechanisms behind these trends are analyzed and discussed in the context of the general structure of the surfactant adsorption layers at various nonpolar phase-water interfaces.
皂苷是一类多样的天然植物衍生表面活性剂，具有独特的分子结构，由一个疏水骨架和一条或多条亲水寡糖链组成。皂苷具有很强的表面活性，在食品饮料、制药、矿石加工等行业用作天然乳化剂和发泡剂。许多皂苷在气 - 水界面形成具有极高表面弹性和粘度的吸附层。从科学和应用的角度来看，皂苷吸附层独特界面粘弹性的分子起源都备受关注。在当前的研究中，我们证明与水接触的疏水相对皂苷的界面性质有非常强烈的影响，并且皂苷吸附层的界面弹性和粘度按以下顺序降低：空气＞十六烷≫三辛酸甘油酯。在各种非极性相 - 水界面处表面活性剂吸附层的一般结构背景下，对这些趋势背后的分子机制进行了分析和讨论。
