Rates of advancing and receding menisci motion, nu, under applied pressure
difference DeltaP in thin methylated quartz capillaries were investigated f
or trisiloxane solution-gas and trisiloxane solution-silicone oil systems.
Dynamic values of the tension of wetting were calculated from the nu(DeltaP
) dependence. Both dynamic surface and interfacial tensions and contact ang
les were assessed. Using solutions of the trisiloxane surfactant, M(D'E8OH)
M, nearly complete displacement of silicone oils from hydrophobed capillari
es becomes possible. Removal of silicone oil films of various viscosities f
rom the methylated surface of thin (about 5 mum in radius) quartz capillari
es using M(D'E8OH)M was investigated. In the case of spontaneous displaceme
nt, the oil film converts into a small oil column in front of the moving me
niscus. The rate of oil film detachment follows diffusion kinetics as a res
ult of penetration of surfactant molecules between the solid surface and th
e oil. Comparison of the volume of a smeared off and detached volume of the
oil shows that silicone oils are displaced nearly completely. Using a vide
o camera, transformation of a flat silicone oil film with base diameter 0.6
mm on a methylated glass surface into a floating spherical oil droplet was
studied. Detachment of the droplet with diameter 0.19 mm occurs very rapid
ly during 14 s. Removal of an oil droplet sitting on an inclined methylated
glass plate occurs as a result of oil emulsification in the course of inte
raction with a thick climbing trisiloxane film flowing around the droplet.
The results obtained show that trisiloxane surfactants may be used not only
as superspreaders but also as cleaning agents.