Negative spreading coefficient

An inversion of these arguments indicates that release agents should exhibit several of the following features (/) act as a barrier to mechanical interlocking (2) prevent interdiffusion (J) exhibit poor adsorption and lack of reaction with at least one material at the interface (4) have low surface tension, resulting in poor wettabihty, ie, negative spreading coefficient, of the release substrate by the adhesive (5) low thermodynamic work of adhesion ... 

Studies by Owen [7] have shown that a negative spreading coefficient, S. defined as... 

If Wab > Wbb, the A-B interaction is sufficiently strong to promote the wetting of A by B. Conversely, no wetting occurs if Wbb > Wab, since the work required to overcome the attraction between two B molecules is not compensated for by the attraction between A and B. Hence, a negative spreading coefficient means that B will not spread over A. 

In the group with negative spreading coefficients (e.g., kerosene-in-water and paraffin-in-water emulsions), the values of in both stirred tanks and bubble columns decrease linearly with an increasing oil fraction. This effect is most... 

Obviously this condition is equivalent to the negative spreading coefficient of substance A on B... 

In the group with negative spreading coefficients (e.g., kerosene-in-water and paraffin-in-water emulsions), the values of kLa in both stirred tanks and bubble columns decrease linearly with an increasing oil fraction. This effect is most likely due to the formation of lens-like oil droplets over the gas-liquid interface. A subsequent slower oxygen diffusion through the droplets, and/or slower rates of surface renewal at the gas-liquid surface, may result in a decrease in kLa. 

Spreading Behavior on Glass of Pure Liquids Having Negative Spreading Coefficients on Bulk Water (All Data 20°C)... 

Fig. 4 Morphologies obtained for three immiscible liquids in colloidal systems for cases A-D with different combinations of positive and negative spreading coefficients (Si, S2, and S3). Reprinted with permission from [55]. Copyright 2011 American Chemical Society...

The driving force Fj, which is the negative spreading coefficient S,... 

---