8. Burst Behavior at a Capillary Tip

Liquid retention in micron and millimeter scale devices is important for maintaining stable interfaces invarious processes including bimolecular separation, phase change heat transfer, and water desalination.There have been several studies of re-entrant geometries, and very few studies on retaining low surfacetension liquids such as fluorocarbon-based dielectric liquids. Here, we study retention of a liquid withvery low contact angles using borosilicate glass capillary tips. We analyzed capillary tips with outerdiameters ranging from 250 to 840 lm and measured Laplace pressures up to 2.9 kPa. Experimentalresults agree well with a numerical model that predicts burst pressure (the maximum Laplace pressurefor liquid retention), which is a function of the outer diameter (D) and capillary exit edge radius ofcurvature (r).

Agonafer, D.D., Lopez, K., Palko, J.W., Won, Y., Palko, J., Santiago, J.G., Goodson, K.E., “Burst behavior at a capillary tip: effect of low and high surface tension”, Journal of Colloid and Interface Science, vol. 55, pp. 1-5, 2015.