Polymer Coatings. Physics and Mechanics of Leveling

Abstract

He received his B.S. de-gree from National Taiwan University in Taiwan (1966), his M.S. degree from The Pennsylvania Stale University (1968), and his Ph.D. degree from Case Western Reserve University (1971). His interests are in rheology, characterization and structure-property relationships of organic coatings, transitions and thermal stability of polymers, and effects of temperature and pressure on the physical properties of polymers. Dr. Quach is a member of the American Chemical Society, Sigma Xi, Phi Lambda Upsilon, and the

Numerical studies of singularity formation at free surfaces and fluid interfaces in two-dimensional Stokes flow

“…Perhaps more importantly, the film levelling flow provides us with an example of a viscous flow that becomes singular at a finite time, in the absence of artificial boundaries where numerical boundary conditions are imposed, and in the absence of singular points in the interior and in the exterior of the flow, including infinity. The significance of the levelling problem for painting and coating technology has been emphasized in a technical review by Quach (1973), and the present results reveal some new modes of unwanted behaviour.…”

Leveling of thixotropic liquids

“…First we will assume that Bo 1, i.e., the wavelength l of the free-surface perturbations is much shorter than the capillary length ( / g) 1/2 , i.e., capillarity dominates gravity in the leveling process. This simplification is supported by observations that little difference exists between paints applied on the floor and on the ceiling [2]. We will also neglect the effect of convection in the evolution of .…”

“…This is the simplest idealization of the shear-thinning pseudo-plastic liquid. Other expressions are available in literature (see for example Quach [2], Barnes [7], Mewis [8], Mewis and Wagner [9], Billingham and Ferguson [10], Cheng and Evans [11], Cohu and Magnin [14], and references therein). According to (9), the shear stress varies linearly across the film thickness…”

“…The hydrodynamic leveling of thin liquid films has been studied extensively since 1920, most particularly for Newtonian liquids (see Dodge [1] and Quach [2], and references therein). Orchard [3] was the first to treat this problem theoretically.…”

Surfactant-induced delay of leveling of inkjet-printed patterns

“…7 Keunings, Iyer, and Bousfield studied the effect of viscoelasticity and shear-thinning on the evolution of coating defects. 12,20 Stillwagon and Larson studied the leveling of thin films deposited on topographically patterned substrates.…”