In the three-liquid-phase coexisting region of the system water + tetradecane + diethylene glycol monohexyl ether (C 6 E 2 ), the middle surfactant-rich phase undergoes a sequence of wetting transitions comprising nonwetting f partial wetting f complete wetting at the interface of oil-rich and water-rich phases as the temperature is raised from its lower critical consolute temperature toward its upper critical consolute temperature (J. Chem. Phys. 1993, 98, 4830). In this study, the effect of oil chain length on the wetting transition in the system water + C 6 E 2 + oil (dodecane, decane, and octane) is investigated by interfacial tension measurements. A sequence of wetting transitions, nonwetting f partial wetting f complete wetting, of the middle C 6 E 2 -rich phase is observed in all three systems while the system temperature increases. A decrease of the oil chain length in the system water + C 6 E 2 + oil would make the three-liquid-phase body shrink and lead the system to approach a tricritical point. The effect of the system water + C 6 E 2 + oil approaching its tricritical point on the wetting behavior of the middle C 6 E 2 -rich phase is discussed.

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This study aims to identify distinct blood flow characteristics in a microchannel at different sloping angles. The channel is determined by a bottom hydrophilic stripe on a glass substrate and a fully covered hydrophobic glass substrate. The channel has a height of 3 lm, and a width of 100 lm. It is observed that increasing the sloping angle from -90°(downward flow) to 90°(upward flow) increases the blood flow rate monotonically. These peculiar behaviors on the micro scale are explained by a dynamic model that establishes the balance among the inertial, surface tension, gravitational, and frictional forces. The frictional force is further related to the effective hematocrit. The model is used to calculate the frictional force, and thus the corresponding hematocrit, which is smaller when the blood flows upward, reducing the frictional force.