Solution, nematic and isotropic phases of rigid rod

The principal goal of this work is to pursue the concept of induced rigidity. Our current investigations include extensions to the cases of arbitrary values of the cooperativity parameter 1 E 0, more accurate treatments of the rod-rod excluded volume interaction,— and the inclusion of some attractive dispersion forces. While we refer to the phase transition as lyotropic, in fact we do expect that it also occurs as a function of temperature (as well as pH, ionic strength, etc.) because of the dependence of s on these parameters. We must further emphasize the semi-quantitative nature of our results. Indeed under most actual circumstances, s and c will not be completely independent variables. Nevertheless we believe that the physical picture presented here has some relation to reality. 

We have previously suggested— that a cooperative helix-coil— nematic phase transition may occur in solutions of heliogenic macromolecules such as the synthetic polypeptides (e.g., PBLG). 

In this study, we extend the model to the more explicit case of excluded volume interactions only. For the special case of fully cooperative isolated molecule helix-coil transitions, we sketch out the phase boundary between isotropic and nematic regions. 

Such systems were discussed in detail at the ACS Symposium or Rigid Chain Polymers, New Orleans, March, 1977, Polymer Preprints (1977) 1, and J. Poly. Sci. (to be published). 

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See also in sourсe #XX -- [ ]

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