Department of Chemical Engineering , Technion-Israel Institute of Technology , Technion City, Haifa 3200003 , Israel.
Jülich Center for Neutron Science, Forschungszentrum Jülich GmbH Outstation at MLZ , 85747 Garching , Germany.
Langmuir. 2018 Jul 31;34(30):8857-8865. doi: 10.1021/acs.langmuir.8b01325. Epub 2018 Jul 19.
Natural cellulose has been used as a coating to stabilize oil-in-water (o/w) emulsions by exploiting the amphiphilic character of the cellulose chains molecularly dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate. Its cellulose coating exhibits a continuous amorphous structure which differs significantly from the cellulose particle stabilization used in Pickering emulsions. The structure of these cellulose-coated o/w emulsion particles, in particular the cellulose coating shell characteristics (thickness, porosity, and composition), is studied by using a combination of direct imaging methods such as cryogenic electron microscopy and fluorescence microscopy with small-angle neutron scattering measurements. This work suggests a unique multicompartment structure of the emulsion particles: an oil core, surrounded by an inner shell composed of a porous cellulose gel, encapsulated by a dense outer cellulose shell, a few nanometers in thickness. The thickness of the inner cellulose shell varies significantly. The nanoscale emulsion droplets exhibit a thickness of 10 ± 3 nm, whereas the larger micron-sized droplets exhibit a thicker inner cellulose shell of 500-750 nm. It is also inferred that the cellulose shells contain water rather than oil.
天然纤维素已被用作通过利用分子溶解在离子液体 1-乙基-3-甲基咪唑醋酸盐中的纤维素链的两亲特性来稳定水包油（o/w）乳液的涂层。其纤维素涂层表现出连续的无定形结构，与用于 Pickering 乳液的纤维素颗粒稳定化有很大的不同。这些纤维素包覆的 o/w 乳液颗粒的结构，特别是纤维素包覆壳的特性（厚度、孔隙率和组成），通过使用低温电子显微镜和荧光显微镜等直接成像方法与小角中子散射测量相结合进行研究。这项工作表明乳液颗粒具有独特的多隔室结构：油芯，由多孔纤维素凝胶组成的内壳包围，并由几纳米厚的致密外壳封装。内纤维素壳的厚度变化很大。纳米级乳液液滴的厚度为 10±3nm，而较大的微米级液滴则具有较厚的 500-750nm 厚的内纤维素壳。还推断纤维素壳含有水而不是油。
