Berthelot tail potential model

The predicted spinodal temperature for the Berthelot A tail potential model is given by ... 

The idealized symmetric blend model is not representative of the behavior of most polymer alloys due to the artificial symmetries invoked. Predictions of spinodal phase boundaries of binary blends of conformationally and interaction potential asymmetric Gaussian thread chains have been worked out by Schwelzer within the R-MMSA and R-MPY/HTA closures and the compressibility route to the thermodynamics. Explicit analytic results can be derived for the species-dependent direct correlation functions > effective chi parameter, small-angle partial collective scattering functions, and spinodal temperature for arbitrary choices of the Yukawa tail potentials. Here we discuss only the spinodal boundary for the simplest Berthelot model of the Umm W t il potentials discussed in Section V. For simplicity, the A and B polymers are taken to have the same degree of polymerization N. 

Consider the same model system as above, but where there are attractive tail potentials, i mm C ) between sites of type M and M on different copolymers. In the numerical examples presented later, the shifted Lennard-Jones attraction of Eq. (5.10) is appended to the SFC diblock model of Section VILA. For simplicity, the Berthelot potential model is... 

The Lennard-Jones potential includes a strongly repelling term proportional to 1 /r A which represents the excluded volume by an atom, and a long attractive tail of the form — 1 /rfj, which models the effect of attractive interactions between induced dipoles due to fluctuating charge distributions. This potential provides reasonable simulation results for the properties of liquid argon. The parameters aij and Sij, the effective diameter and the depth of the potential well between different atoms, can be calculated by using the combination rules since normally the effective diameter and the depth of the potential well are only available for the atoms of individual elements. The most frequently used combination rule is the Lorentz-Berthelot formula ... 

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