(383h) Dynamics of Liquid Bridge Between Capillary and Substrate Via 3D Spectral Boundary Elements
Microlithography is an emerging technique to create micron-sized features on substrate. New capillary based lithography method has been developed to overcome the limitations (e.g. direct contact with the substrate) of existing lithography techniques including dip-pen nanolithography, nano-imprint lithography, and electron-beam lithography. The understanding of the behavior of the liquid bridge formed between a capillary tube and a substrate is essential for the recently developed capillary based lithography method that is non-invasive to the substrate. A three-dimensional spectral boundary element method has been employed and adapted to describe the dynamics of the liquid bridge. Starting with a steady-state liquid bridge shape, the transient bridge deformation is computed as the capillary tube is retracting away from the substrate. Slip boundary conditions are introduced to the bridge-substrate contact line. Several relations between the dynamic contact angle and contact line speed are employed and discussed. The influences of liquid properties and retracting speed on the bridge dynamics are investigated. The numerical approach has been validated by comparing with experimental findings. This study is supported in part by the Department of Energy under award #DE-FG52-08NA28921 and National Science Foundation EPS-0814442 through ND EPSCoR.