Mun Saehun, McClements D Julian
Biopolymers and Colloids Research Laboratory, Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Langmuir. 2006 Feb 14;22(4):1551-4. doi: 10.1021/la052575l.
The influence of the nature of the interfacial membrane on the kinetics of droplet growth in hydrocarbon oil-in-water emulsions was investigated. Droplet growth rates were determined by measuring changes in the droplet size distribution of 1 wt % n-tetradecane or n-octadecane oil-in-water emulsions using laser diffraction. The interfacial properties of the droplets were manipulated by coating them with either an SDS layer or with an SDS-chitosan layer using an electrostatic deposition method. The emulsion containing SDS-coated octadecane droplets did not exhibit droplet growth during storage for 400 h, which showed that it was stable to Ostwald ripening because of this oils extremely low water-solubility. The emulsion containing SDS-coated n-tetradecane droplets showed a considerable increase in mean droplet size with time, which was attributed to Ostwald ripening associated with this oils appreciable water-solubility. On the other hand, an emulsion containing SDS-chitosan coated n-tetradecane droplets was stable to droplet growth, which was attributed to the ability of the interfacial membrane to resist deformation because of its elastic modulus and thickness. This study shows that the stability of emulsion droplets to Ostwald ripening can be improved by using an electrostatic deposition method to form thick elastic membranes around the droplets.
研究了界面膜的性质对水包油型碳氢化合物乳液中液滴生长动力学的影响。通过使用激光衍射测量1 wt%正十四烷或正十八烷水包油乳液的液滴尺寸分布变化来确定液滴生长速率。使用静电沉积法，通过用SDS层或SDS-壳聚糖层包覆液滴来控制液滴的界面性质。含有包覆SDS的十八烷液滴的乳液在储存400小时期间未表现出液滴生长，这表明由于该油极低的水溶性，它对奥斯特瓦尔德熟化具有稳定性。含有包覆SDS的正十四烷液滴的乳液随着时间的推移平均液滴尺寸显著增加，这归因于与该油可观的水溶性相关的奥斯特瓦尔德熟化。另一方面，含有包覆SDS-壳聚糖的正十四烷液滴的乳液对液滴生长具有稳定性，这归因于界面膜因其弹性模量和厚度而抵抗变形的能力。本研究表明，通过使用静电沉积法在液滴周围形成厚的弹性膜，可以提高乳液液滴对奥斯特瓦尔德熟化的稳定性。
