Flory model polyelectrolytes

Flory PJ (1953) Principles of polymer chemistry. Cornell University Press, Ithaca, NY Ciinther M, Cerlach C, Wallmersperger T (2007) Modeling of nonlinear effects in pH-sensors based on polyelectrolytic hydrogels. In Bar-Cohen Y (ed) Proceedings of the SPIE Electroactive Polymer Actuators and Devices, vol. 6524. p 652416f... 

Reliable theories that accurately correlate or predict polyelectrolyte phase diagrams are lacking. Letting electrostatic excluded volume between chain segments be modeled at the level of the Debye-Hiickel approximation, a modified or effective Flory-Huggins parameter Xeff can be determined via the random phase approximation (141) ... 

But the concentrated phase is in equilibrium with a diluted phase which is not consistently described by a Flory-Huggins model it is difficult to imagine that a diluted solution of the two types of polyelectrolytes with an opposite global charge and a rather stiff conformation can be treated by the lattice formalism. 

The contribution of the elastic term in lightly cross-linked networks can be described by the Gaussian theory of rubber elasticity (2,3). In fully neutralized polyelectrolytes, in the presence of added salt, the ionic term is not expected to play an exphcit role. Ionic interactions, however, may modify the mixing free energy contribution. In neutral polymer solutions the Flory-Huggins theory (I), based on the lattice model of solutions, expresses the mixing pressure as... 

---