Chain repulsion

The second-order parameter to expresses the special "around the chain".repulsion between two pivaloyl groups in the racemic tt conformation. 

Tts Surface pressure (from carbon chains repulsion)... 

Figure 7.4 Cartoon showing the transverse pressure profile in a monolayer of an ionic surfactant, showing the regions of steric chain repulsion, electrostatic repulsion, and bare oil-water attraction. The area under the Ap vs. z curve represents the interfacidl tension, and the area under the Ap(z)z vs. z curve is equal to —2kH< i.e. proportional to the spontaneous curvature...

Here, A is the ideal-gas contribution represents the hard-chain repulsion of the reference system. A P and A account for the Helmholtz energy contributions due to attraction (dispersion) and hydrogen bonding (association), respectively. To account for the fact that at least some of the species carry charges, this model was combined with a Debye-Hiickel theory to describe the Helmholtz energy contribution A to a system that is caused by charging the species. 

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