Linear dependence of surface drag on surface viscosity.
Flow at an air-water interface is limited by drag from both the two-dimensional surface and three-dimensional subphase. Separating these contributions to the interfacial drag is necessary to measure surface viscosity as well as to understand the influence of the interface on flow. In these experiments, a magnetic needle floating on a monolayer-covered air-water interface is put in motion by applying a constant magnetic force, F(m). The needle velocity varies exponentially with time, reaching a terminal velocity F(m)/C, in which C is the drag coefficient. C is shown to be linearly proportional to the monolayer surface viscosity, eta(s), for dipalmitoylphosphatidylcholine monolayers in the condensed phase by comparison to surface viscosity measured by channel viscometry.
Departments of Chemical Engineering and Materials, University of California, Santa Barbara, California 93106-5080, USA.
Coralie
C
Alonso
Joseph A
JA
Zasadzinski
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D003198:Computer Simulation; D019544:Equipment Failure Analysis; D017276:Friction; D016014:Linear Models; D008280:Magnetics; D008956:Models, Chemical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014159:Transducers; D014783:Viscosity
D015060:1,2-Dipalmitoylphosphatidylcholine