Free-Meniscus Coating Processes

摘要: When faced with depositing a liquid film on surface, laboratory scientists usually rely free coating by withdrawal or drainage, so-called free-meniscus coating. Simplistic and inexpensive, these techniques abound in the research development of materials that can be deposited state. What has come to known as dip (Deryagin Levi 1964; Ruschak 1976; Scriven 1988), viscous lifting (Van Rossum 1958), drag-out (Landau Levich 1942) begins immersing substrate vessel filled liquid. Withdrawal from liquid, if managed properly, result thin coherent film, shown Fig. 13.1b. Alternatively, drained around substrate. This technique is often referred coating-by-drainage (Jeffreys 1930; Van 1958; Groenveld 1971) diagrammed 13.1c. Recourse sometimes taken when limited vertical space prevents (cf. Ashley Reed 1984) small, short substrates avoid local thickening obtained trailing edge withdrawn (Schroeder 1969). Although most operated batch process, it made continuous (Fig. 13.1d) long, flexible sheet filament 1988); however, sustaining process requires addition make-up vessel. In any case, physics coating, are essentially same, differing only frame reference which flat part meniscus stationary.