Surfactant spreading on a thin viscous film, in the presence of a pre-existing surfactant distribution, is investigated experimentally. The experiments are designed to provide a better understanding of the fundamental interfacial and fluid dynamics for spreading of an exogenous surfactant instilled into the lung. Quantitative measurements of spreading rates were conducted using a fluorescent exogenous surfactant (1-16:0-2-[12-[(7-nitro-2-1, 3-benzoxadiazol-4-yl)amino]dodecanoyl] phosphatidylcholine) that was excited by argon laser light as it spread on an air-glycerin interface in a petri dish. This interface was either clean or contained a level of non-fluorescent, pre-existing surfactant(palmitoyl-lauroyl-sn-glycero- 3-phosphocholine) which was varied. The surface behavior of these similar agents was shown to be nearly identical. It is found that pre-existing surfactant impedes surfactant spreading. However, fluorescent microspheres used as surface markers show that pre-existing surfactant facilitates the propagation of a compression-wave disturbance which travels faster than the leading edge of the new surfactant. The experimental results are compared to a mathematical model that accounts for the finite domain of the petri dish. The experimental results compare well with the theory.
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology