Tamura T, Kageyama M, Kaneko Y, Kishino T, Nikaido M
Material Science Research Center, Lion Corporation, 7-13-12, Hirai, Edogawa-ku, Tokyo, 132, Japan
J Colloid Interface Sci. 1999 May 1;213(1):179-186. doi: 10.1006/jcis.1999.6125.
It is well known that the stability of a pseudoemulsion film, a thin liquid film formed between an antifoam particle and air, can be important during defoaming action. We have compared the bursting behavior of a two-dimensional thin liquid film from an aqueous surfactant solution on a glass plate, in which six types of antifoam particles have been dispersed, using laser microscopic techniques. The used antifoams were a silicone oil, a mixed-type antifoam (mixture of silicone oil and hydrophobic solid particles), a hydrophobic silica, and a silicone-based solid antifoam (prepared by interfacial polymerization with oil and water). The antifoaming performance of these six types of antifoams, measured by the glass cylinder shaking test, was in the order: the mixed-type antifoam >== the silicone-based solid antifoam > the hydrophobic silica >== the silicone oil. Pseudoemulsion film rupture was observed at the film thickness less than 0.1 µm for both the silocone oil and the hydrophobic silica. In the case of particles with rough edges (the silicone-based antifoam), pseudoemulsion film on the top of the particles can be easily ruptured at a convex part of the solid surface. Furthermore, solid particles existing on the surface of an oil droplet in the mixed-type antifoams form marked projections and these projections give rise to distortion of the thinning film. As soon as the distortion of the thinning film took place on the top of the antifoam droplet, the pseudoemulsion film can be instantaneously ruptured. Referring to the antifoaming mechanisms for mixed-type antifoams, both steps from the pseudoemulsion film formation to the lens formation and from the counter pseudoemulsion film formation to the bridge formation would be very fast and cause a very high antifoaming efficiency. Copyright 1999 Academic Press.
众所周知，在消泡过程中，消泡剂颗粒与空气之间形成的伪乳液膜（一种薄液膜）的稳定性可能很重要。我们使用激光显微镜技术比较了在玻璃板上含有六种消泡剂颗粒的水性表面活性剂溶液形成的二维薄液膜的破裂行为。所使用的消泡剂有硅油、混合型消泡剂（硅油和疏水性固体颗粒的混合物）、疏水性二氧化硅和硅基固体消泡剂（通过油与水的界面聚合制备）。通过玻璃圆筒振荡试验测得的这六种消泡剂的消泡性能顺序为：混合型消泡剂＞硅基固体消泡剂＞疏水性二氧化硅＞硅油。对于硅油和疏水性二氧化硅，在膜厚度小于0.1 µm时观察到伪乳液膜破裂。对于边缘粗糙的颗粒（硅基消泡剂），颗粒顶部的伪乳液膜在固体表面的凸部很容易破裂。此外，混合型消泡剂中油滴表面存在的固体颗粒形成明显的凸起，这些凸起导致变薄膜的变形。一旦在消泡剂液滴顶部发生变薄膜的变形，伪乳液膜就会瞬间破裂。关于混合型消泡剂的消泡机理，从伪乳液膜形成到透镜形成以及从反伪乳液膜形成到桥形成这两个步骤都非常快，从而导致非常高的消泡效率。版权所有1999年学术出版社。
