Fluidic flow is directed in a capillary or channel in a miniaturized separation or microfluidic device by the addition of liquid crystals to the fluid filling the channel. The liquid crystal medium undergoes changes in morphology upon the addition of external stimuli (magnetic and/or electric field and temperature). Under appropriate conditions this externally triggered change in liquid crystal produces a change in viscosity. This triggered change in viscosity directs fluid flow in multiple path channels and/or capillaries and therefore serves as a means of directing and controlling fluid flow within a capillary or channel in a miniaturized separation or microfluidic device.