REMOVAL OF ORGANIC FILMS FROM SOLID-SURFACES USING AQUEOUS-SOLUTIONS OF NONIONIC SURFACTANTS .2. THEORY

The removal of organic films of solder flux components (abietic acid i n isopropyl alcohol) from disks of epoxy-glass laminate by aqueous sol utions of nonionic surfactant (C(12)E(5)) proceeds through three stage s. The controlling mechanisms in each stage were deduced from experime ntal observations. In this paper, theoretical models are developed to analyze the cleaning rates in the three different stages. The duration of the first stage is calculated assuming that convective and diffusi ve transport of surfactant monomer into the organic film controls the stage. The second stage is analyzed considering that shear forces remo ve aggregates from a continuous film of liquefied residue, while the t hird stage cleaning rate model is based on the shear-induced removal o f isolated aggregates adsorbed directly to the solid substrate. Parame ters in the models are evaluated using experimental cleaning rate data .