Perturbation theory of isotropic-liquid-crystal phase equilibria in polyelectrolyte solutions

✍ Scribed by Takahiro Sato; Akio Teramoto

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 853 KB
• Volume: 176
• Category: Article
• ISSN: 0378-4371
• DOI: 10.1016/0378-4371(91)90434-e

✦ Synopsis

The excess Helmholtz free energy AF of rodlike and wormlike polyelectrolyte solutions over that of solvent is formulated from a perturbation theory, where the hard core and electrostatic potentials between two polymers are taken as the pair potentials of the reference system and the perturbation, respectively. The free energy of the reference system is obtained from a scaled particle theory for hard spherocylinders, while the perturbation terms are evaluated by the second virial approximation. The polyelectrolyte end effect on the electrostatic binary cluster integral is taken into account along with the contribution of polyions and their counterions to the electrostatic screening. The phase boundary concentrations for the isotropic-liquid-crystal phase equilibria in polyelectrolyte solutions are calculated from AF in order to compare them with experimental data for aqueous xanthan (a rigid double helical polysaccharide) and tobacco mosaic virt~s. The agreement between theory and experiment is almost quantitative for the former system, but not so satisfactory for the latter.