BRIEF DESCRIPTION OF THE DRAWINGS [0014]FIG. 1 is a perspective, greatly enlarged view of an ultraphobic surface according to the present invention; [0015]FIG. 1a is a schematic view of a liquid slug in a flow channel; [0016]FIG. 1b is an exploded view of a microfluidic device according to the present invention; [0017]FIG. 1c is a cross-sectional view of an alternative embodiment of a microfluidic