Steric repulsion between internal aqueous droplets and the external aqueous phase in double emulsions.
A theoretical model for analyzing the steric repulsion energy between internal aqueous droplets and the external aqueous phase in double emulsions, which results from the steric interaction between the surfactant molecules adsorbed at the two interfaces, has been established. The steric interaction is dependent on the separation distance between the internal aqueous droplets and the external aqueous phase, the thicknesses of the two adsorbed surfactant layers, and the size of the internal aqueous droplets and the oil globules, all of which determine the extent of the compression of the adsorbed surfactant molecules. The thickness of each of the two surfactant layers have the same effect on the steric repulsion, and stronger steric interaction can be achieved with thicker adsorbed layers, which can effectively prevent coalescence between the internal aqueous droplets and the external aqueous phase. Increasing the internal aqueous droplet size can produce stronger steric repulsion; however, larger oil globules will weaken the steric repulsion, indicating that a more stable double-emulsion system can be achieved by preparing the system with smaller oil globules and larger internal aqueous droplets.
Cheng
Jing
J
Key Lab for Nanomaterials, Ministry of Education, Research Center of the Ministry of Education for High Gravity Engineering & Technology, Beijing University of Chemical Technology, China.
Xu
Shiai
S
Wen
Lixiong
L
Chen
Jianfeng
J
D004655:Emulsions; D013501:Surface-Active Agents; D014867:Water
D004655:Emulsions; D013501:Surface-Active Agents; D014867:Water