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Asymptotic Analysis Of Liquid Films Dip-Coated Onto Chemically Micropatterned Surfaces, Jm Davis
Asymptotic Analysis Of Liquid Films Dip-Coated Onto Chemically Micropatterned Surfaces, Jm Davis
Jeffrey M. Davis
The dip coating of chemically heterogeneous surfaces is a useful technique for attaining selective material deposition. For the case of vertical, wetting stripes surrounded by nonwetting regions, experiments have demonstrated that the thickness of the entrained film on the stripes is significantly different than on homogeneous surfaces because of the lateral confinement of the liquid. In the present work, the asymptotic matching of equations based on lubrication theory is used to determine the film thickness, and necessary restrictions on the capillary and Bond numbers are provided. The predictions are in excellent agreement with the existing experimental data, and the classical …
Generalized Linear Stability Of Noninertial Coating Flows Over Topographical Features, Jm Davis, Sm Troian
Generalized Linear Stability Of Noninertial Coating Flows Over Topographical Features, Jm Davis, Sm Troian
Jeffrey M. Davis
The transient evolution of perturbations to steady lubrication flow over a topographically patterned surface is investigated via a nonmodal linear stability analysis of the non-normal disturbance operator. In contrast to the capillary ridges that form near moving contact lines, the stationary capillary ridges near trenches or elevations have only stable eigenvalues. Minimal transient amplification of perturbations occurs, regardless of the magnitude or steepness of the topographical features. The absence of transient amplification and the stability of the ridge are explained on physical grounds. By comparison to unstable ridge formation on smooth, flat, and homogeneous surfaces, the lack of closed, recirculating …