Le Mans Université, IMMM UMR-CNRS 6283, 72085, cedex 9, Le Mans, France.
Le Mans Université, IMMM UMR-CNRS 6283, 72085, cedex 9, Le Mans, France.
Carbohydr Polym. 2022 Feb 1;277:118812. doi: 10.1016/j.carbpol.2021.118812. Epub 2021 Oct 28.
Water in water emulsions were prepared by mixing aqueous solutions of dextran and poly(ethylene oxide) at three volume fractions. The xanthan was added to the emulsions up to 0.5 wt%. The stability of the emulsions was probed by measuring the time dependence of the transmission profiles at different centrifugal forces. At lower concentrations, xanthan partitioned to the dextran phase and strong shear-thinning was observed at higher concentrations. At lower concentrations, destabilization was caused by a combination of coalescence and creaming or sedimentation. Above 0.1 wt%, xanthan strongly increased the viscosity of the emulsions and stabilized them under gravity for at least one week. The time evolution of the emulsion microstructure was observed using confocal scanning laser microscopy. The effect of shear on the microstructure was investigated using a specific rheo-optical device. It showed the formation of thin strands that broke up into small drops after stopping the flow.
水包水乳液是通过将葡聚糖和聚氧化乙烯的水溶液在三个体积分数下混合制备的。黄原胶被添加到乳液中，最高可达 0.5wt%。通过测量不同离心力下的传输谱的时间依赖性来探测乳液的稳定性。在较低的浓度下，黄原胶分配到葡聚糖相中，在较高的浓度下观察到强烈的剪切变稀。在较低的浓度下，失稳是由聚结和乳状液或沉降的组合引起的。在 0.1wt%以上，黄原胶强烈增加了乳液的粘度，并在重力下至少稳定一周。使用共焦扫描激光显微镜观察乳液微观结构的时间演变。使用特定的流变光学装置研究了剪切对微观结构的影响。结果表明，在停止流动后，形成了薄的链，这些链断裂成小滴。
