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.
Alonso
Coralie
C
Departments of Chemical Engineering and Materials, University of California, Santa Barbara, California 93106-5080, USA.
Zasadzinski
Joseph A
JA
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