Film elasticity character

Nonsurface-active PS as X strongly increase the surface pressure and the elastic character of the interfacial film. This imexpected behavior would arise from incompatibility with the aqueous bulk phase and possible complexation onto the adsorbed protein. 

Film Elasticity The differential change in surface tension of a surface film with relative change in area. Also termed surface elasticity, dilata-tional elasticity, areal elasticity, compressional modulus, surface dilata-tional modulus, or modulus of surface elasticity. For fluid films, the surface tension of one surface is used. The Gibbs film (surface) elasticity is the equilibrium value. If the surface tension is dynamic (time-dependent) in character, then for nonequilibrium values, the term Marangoni film... 

Mohammed et al. [55] published a series of papers in which they probed the rheology, interfacial tension, surface pressure, and compressional modulus of crude oil-water interfaces with and without added demulsifiers under thermal and electrical fields. They observed that with short aging times of the crude oil-water interface, the interface rheology could be characterized as substantially viscous, but with very little elastic character. They demonstrated that thick viscoelastic films tended to accumulate in aged films and that some demulsifiers prevented such accumulations. 

Under these circumstances [said Davy] a vivid action was soon observed to take place. The potash began to fuse at both its points of electrization. There was a violent effervescence at the upper surface at the lower, or negative, surface, there was no liberation of elastic fluid but small globules having a high metallic lustre, and being precisely similar in visible characters to quicksilver, appeared, some of which burnt with explosion and bright flame, as soon as they were formed, and others remained, and were merely tarnished, and finally covered by a white film which formed on their surfaces. 

The chemical structures of the lipid studied are shown in the Fig. 1. There are two different types of behavior for monolayers from those lipid mixtures (i) solid film formation with relatively low pressure of a collapse (cholesterol rich monolayers) and (ii) viscous elastic film formation, when the concentration of CHL is less 30% in the monolayer. The character of the behavior of a monolayer is quite similar upon replacing of CHL by Q3P, though the LB film morphology is essentially different. 

Viscometric determinations of these phenomena all involve the destruction of the very structures that one sets out to measure and therefore are not emphasized in this chapter. It is more important to recognize the partial solidlike character of film formers at the outset and to treat them in a manner that elucidates both the solid and the liquid characteristics in the same nondestructive measurement. That is, one should measure viscosity and elasticity simultaneously. 

The brittleness and crystalline character of the films was emphasized by the deformation test. The linear viscoelastic regime (the deformation range at Fig. 6c which the films are deformed reversible) was limited to deformations of about 0.1%, which is an extremely low value. This points to the presence of energy elastic systems. As a compromise to the resolution of the measuring device, in the other test setups the applied strain was set to 0.1 or 0.2%. 

Dow developers and partners having first access to these materials have explored the use of OBCs for various industrial applications such as elastic films, fibers, soft touch materials, extmded profiles, injection molded articles, and so on. For example, polyolefin oil-filled systems used to make compounds for soft touch handles, grips, and gaskets benefit from inaeased elastic performance and temperature resistance. Other examples include adhesives that utilize OBCs with low hard block contents to obtain the soft adhesive character but at the same time offer the cohesive strength and heat resistance required for demanding pressure sensitive adhesives. ... 

---