Long-Lived and Thermoresponsive Emulsion Foams Stabilized by Self-Assembled Saponin Nanofibrils and Fibrillar Network
Long-Lived and Thermoresponsive Emulsion Foams Stabilized by Self-Assembled Saponin Nanofibrils and Fibrillar Network
复制标题
自组装皂苷纳米纤维和纤维网络稳定的长寿命和热响应乳液泡沫
DOI：
10.1021/acs.langmuir.8b00128
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Yang Xiaoquan
中科院分区：
文献类型：
--
作者：
Wan Zhili;Sun Yingen;Ma Lulu;Zhou Feibai;Guo Jian;Hu Songqing;Yang Xiaoquan
来自天然皂苷甘草酸（GA）自组装的纳米原纤维可用于生产具有长期稳定性的水包油乳液泡沫。通过均质、通气和快速冷却，葵花籽油和皂苷纳米原纤维的混合物可以产生稳定的乳液泡沫。在高温下，GA原纤维在界面处形成多层组件，形成界面原纤维网络，以稳定均质过程中产生的油滴和气泡。随后的快速冷却可以触发连续相中游离 GA 原纤维的自组装，形成原纤维水凝胶，从而捕获油滴和气泡。粘弹性块状水凝胶表现出高屈服应力和储能模量，从而完全阻止液体排出并大大减缓乳液泡沫中气泡的粗化。还发现液体通道中以及气泡周围的乳液液滴的堵塞能够增强泡沫稳定性。我们表明，由于大块水凝胶的熔化，这种稳定的泡沫系统可以通过加热按需快速破坏。 GA水凝胶的可逆凝胶-溶胶相变形成热响应性乳液泡沫，只需升高温度即可将泡沫稳定性从稳定状态转变为不稳定状态。通过加入炭黑颗粒等内部热源，可以将乳液泡沫进一步开发为光响应性，炭黑颗粒可以吸收紫外线照射并将吸收的光能转化为热能。这种由天然、可持续的皂苷纳米纤维稳定的新型智能响应乳液泡沫在食品、制药和个人护理行业具有潜在的应用。
Nanofibrils from the self-assembly of the naturally occurring saponin glycyrrhizic acid (GA) can be used to produce an oil-in-water emulsion foam with a long-term stability. Through homogenization and aeration followed by rapid cooling, stable emulsion foams can be produced from the mixtures of sunflower oil and saponin nanofibrils. At high temperatures, the GA fibrils form a multilayer assembly at the interface, creating an interfacial fibrillar network to stabilize the oil droplets and air bubbles generated during homogenization. A subsequent rapid cooling can trigger the self-assembly of free GA fibrils in the continuous phase, forming a fibrillar hydrogel and thus trapping the oil droplets and air bubbles. The viscoelastic bulk hydrogel showed a high yield stress and storage modulus, which lead to a complete arrest of the liquid drainage and a strong slowdown of the bubble coarsening in emulsion foams. The jamming of the emulsion droplets in the liquid channels as well as around the bubbles was also found to be able to enhance the foam stability. We show that such stable foam systems can be destroyed rapidly and on demand by heating because of the melting of the bulk hydrogel. The reversible gel–sol phase transition of the GA hydrogel leads to thermoresponsive emulsion foams, for which the foam stability can be switched from stable to unstable states by simply raising the temperature. The emulsion foams can be further developed to be photoresponsive by incorporating internal heat sources such as carbon black particles, which can absorb UV irradiation and convert the absorbed light energy into heat. This new class of smart responsive emulsion foams stabilized by the natural, sustainable saponin nanofibrils has potential applications in the food, pharmaceutical, and personal care industries.