Effect Marangoni

It is clear that the molecules present in a monolayer interact with the molecules of the underlying liquid phase and cannot be assumed merely to consist of molecules moving freely in two dimensions. Such interactions result in molecular motions energized by surface tension gradients this is called the Marangoni effect. In a glass of wine, ethyl alcohol 

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The Marangoni effect has been observed on the rapid compression of a monolayer [54] and on application of an electric held, as in Ref. [55] it occurs on evaporation [56]. 

In a foam where the films ate iaterconnected the related time-dependent Marangoni effect is mote relevant. A similar restoring force to expansion results because of transient decreases ia surface concentration (iacteases ia surface tension) caused by the finite rate of surfactant adsorption at the surface. 

Information on the coefficients is relatively undeveloped. They are evidently strongly influenced by rate of drop coalescence and breakup, presence of surface-active agents, interfacial turbulence (Marangoni effect), drop-size distribution, and the like, none of which can be effectively evaluated at this time. 

Increase adhesion tension. Maximize surface tension. Minimize contact angle. Alter surfactant concentration or type to maximize adhesion tension and minimize Marangoni effects. Precoat powder with wettahle monolayers, e.g., coatings or steam. Control impurity levels in particle formation. Alter crystal hahit in particle formation. Minimize surface roughness in milhng. 

Tills phenomenon, frequently referred to as the Marangoni Effect, explains some of the anomalously high mass transfer rates reported in the literature. 

A is the area of the surface. In a foam, where the surfaces are interconnected, the time-dependent Marangoni effect is important. A restoring force corresponding to the Gibbs elasticity will appear, because only a finite rate of absorption of the surface-active agent, which decreases the surface tension, can take place on the expansion and contraction of a foam. Thus the Marangoni effect is a kinetic effect. 

All of these disturbances cause a many-fold increase in the rate of transfer of solute across the interface. If a chemical or thermal difference along an interface causes an interfacial tension gradient, violent flow in the direction of low a will result. This action is usually termed the Marangoni effect. 

U. Influence of the Marangoni Effect on the Mass Transfer BETWEEN Two PHASES... 

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