Abstract
Adsorption of phosphatidylcholines at oil/water interfaces strongly deviates from spread monolayers at air/water surfaces. Understanding its nature and consequences could vastly improve applications in medical nanoemulsions and biotechnologies. Adsorption kinetics at interfaces of water with different oil phases were measured by profile analysis tensiometry. Adsorption kinetics for 2 different phospholipids, DPPC and POPC, as well as 2 organic phases, squalene and squalane, show that formation of interfacial monolayers is initially dominated by stress-relaxation in the first minutes. Diffusion only gradually contributes to a decrease in interfacial tension at later stages of time and higher film pressures. The results can be applied for the optimization of emulsification protocols using mechanical treatments. Emulsions using phospholipids with unsaturated fatty acids are dominated much more strongly by stress-relaxation and cover interfaces very fast compared to those with saturated fatty acids. In contrast, phospholipid layers consisting of saturated fatty acids converge faster towards the equilibrium than those with unsaturated fatty acids.
| Original language | English |
|---|---|
| Pages (from-to) | 3730-3737 |
| Number of pages | 8 |
| Journal | Soft Matter |
| Volume | 14 |
| Issue number | 19 |
| DOIs | |
| Publication status | Published - 1 Jan 2018 |
Funding
The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7 (2007–2013) under REA grant agreement no. 324275 (project acronym Decent AID). We gratefully thank Lipoid GmbH, Ludwigshafen, Germany, for kindly donating phospholipids for this research.