Long-term stabilization of foams and emulsions with in-situ formed microparticles from hydrophobic cellulose
Long-term stabilization of foams and emulsions with in-situ formed microparticles from hydrophobic cellulose
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DOI：
10.1021/la801634j
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发表时间：
2008-09-02
期刊：
影响因子：
3.9
通讯作者：
Velev, Orlin D.
中科院分区：
文献类型：
--
作者：
Wege, Hartmut A.;Kim, Sejong;Velev, Orlin D.
我们报告了一种简单的方法，通过使用疏水性纤维素微粒，这是由液-液分散技术原位形成的泡沫和乳液的非凡的稳定性。首先将疏水性纤维素衍生物羟丙甲纤维素邻苯二甲酸酯（HP）溶解在水混溶性溶剂如丙酮和乙醇/水混合物中。当这些HP储备溶液在水性介质中剪切时，通过溶剂磨损形成微米尺寸的纤维素颗粒。我们还设计和研究了一种有效的和简单的方法来制备HP颗粒，没有任何有机溶剂。其中溶剂和反溶剂都是不同pH的水性缓冲溶液。因此，HP颗粒吸附在剪切共混期间产生的水/空气或水/油界面上，导致高度稳定的泡沫或泡沫/乳液。HP颗粒的形成及其界面的短期和长期稳定化能力强烈依赖于原液中的HP浓度，以及原液和连续相介质的溶剂化学。一些泡沫和乳液样品形成的存在下钙。1重量% HP可稳定数月。这类新型无毒廉价的纤维素基颗粒稳定剂具有替代传统合成表面活性剂的潜力，特别是在食用、药用和可生物降解产品中。
We report a simple method to produce foams and emulsions of extraordinary stability by using hydrophobic cellulose microparticles, which are formed in situ by a liquid-liquid dispersion technique. The hydrophobic cellulose derivative, hypromellose phthalate (HP), was initially dissolved in water-miscible solvents such as acetone and ethanol/ water mixtures. As these HP stock solutions were sheared in aqueous media, micron sized cellulose particles formed by the solvent attrition. We also designed and investigated an effective and simple process for making HP particles without any organic solvents. where both the solvent and antisolvent were aqueous buffer solutions at different pH. Consequently, the HP particles adsorbed onto the water/air or water/oil interfaces created during shear blending, resulting in highly stable foams or foam/emulsions. The formation of HP particles and their ability for short-term and long-term stabilization of interfaces strongly depended on the HP concentration in stock solutions, as well as the solvent chemistry of both stock solutions and continuous phase media. Some foams and emulsion samples formed in the presence of ca. 1 wt% HP were stable for months. This new class of nontoxic inexpensive cellulose-based particle stabilizers has the potential to substitute conventional synthetic surfactants, especially in edible, pharmaceutical and biodegradable products.